Gene Summary

Gene:PRKAR1A; protein kinase cAMP-dependent type I regulatory subunit alpha
Summary:cAMP is a signaling molecule important for a variety of cellular functions. cAMP exerts its effects by activating the cAMP-dependent protein kinase, which transduces the signal through phosphorylation of different target proteins. The inactive kinase holoenzyme is a tetramer composed of two regulatory and two catalytic subunits. cAMP causes the dissociation of the inactive holoenzyme into a dimer of regulatory subunits bound to four cAMP and two free monomeric catalytic subunits. Four different regulatory subunits and three catalytic subunits have been identified in humans. This gene encodes one of the regulatory subunits. This protein was found to be a tissue-specific extinguisher that down-regulates the expression of seven liver genes in hepatoma x fibroblast hybrids. Mutations in this gene cause Carney complex (CNC). This gene can fuse to the RET protooncogene by gene rearrangement and form the thyroid tumor-specific chimeric oncogene known as PTC2. A nonconventional nuclear localization sequence (NLS) has been found for this protein which suggests a role in DNA replication via the protein serving as a nuclear transport protein for the second subunit of the Replication Factor C (RFC40). Several alternatively spliced transcript variants encoding two different isoforms have been observed. [provided by RefSeq, Jan 2013]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:cAMP-dependent protein kinase type I-alpha regulatory subunit
Source:NCBIAccessed: 30 August, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 30 August 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 30 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PRKAR1A (cancer-related)

Ma S, Liu W, Zhang A, et al.
Identification of a PRKAR1A mutation (c.491_492delTG) in familial cardiac myxoma: A case report.
Medicine (Baltimore). 2019; 98(11):e14866 [PubMed] Free Access to Full Article Related Publications
RATIONALE: Cardiac myxoma is the most common cardiac neoplasm. Currently, there are not many reports on familial cardiac myxoma. Herein, we reported 2 first-degree relatives with left atrial myxoma.
PATIENT CONCERNS: A 20-year-old female was admitted in our hospital for lapsing into a coma for 24 hours, and was diagnosed with recurrent left atrial cardiac myxoma. The patient's father also had a history of cardiac myxoma.
DIAGNOSIS: The patient was diagnosed with left atrial myxoma using transthoracic echocardiography (TTE). Whole exome sequencing (WES) identified a p.Val164Aspfs (c.491-492delTG) mutation in the cAMP-dependent protein kinase A (PKA) regulatory (R) subunit 1 (PRKAR1A) gene for both the proband and her father, but not in her uncle and brother, who had not shown manifestation of cardiac myxoma by the time of this report.
INTERVENTIONS: The myxoma resection was performed following the standard procedure of open chest surgery.
OUTCOMES: The tumor was successfully removed along with the tuberculum. The patient recovered well and was discharged home. No recurrence occurred during 1-year follow-up.
LESSONS: Our findings suggest that PRKAR1A mutation (c.491_492delTG) may be associated with cardiac myxoma, and genetic counseling and specific locus mutation tests may contribute to assessing the risk of cardiac myxoma.

Liu CH, Ge YL, Wu NJ, Jin XP
Hyperglycemia and Hypokalemia in a 16-Year-Old Overweight Female Patient Misdiagnosed with Cushing Syndrome at First and Ultimately Diagnosed with Carney Complex Proven by PRKAR1A Gene Test: a Case Report and Literature Review.
Clin Lab. 2019; 65(3) [PubMed] Related Publications
BACKGROUND: Here we report on a 16-year-old female patient with typical Cushingoid features who was admitted because of purple striae, menostasis, and microsomia for 1 year, and laboratory tests showed hyperglycemia and hypokalemia.
METHODS: For diagnosis, we employed a hormone test, abdominal and pituitary computed tomography scan, ultrasonography to detect endocrine and cardiocutaneous lesions. DNA sequencing to detect PRKAR1A gene mutation to make differential diagnosis for Cushing Syndrome.
RESULTS: Hormone test revealed hypercortisolism, images demonstrated right adrenal nodular hyperplasia and hyperparathyroid hyperplasia. DNA sequencing analysis revealed a heterozygous C.680 G>A substitution in PRKAR1A.
CONCLUSIONS: We describe here an atypical Carney Complex (CNC) patient magnified Cushing Syndrome with a nonsense mutation in the PRKAR1A gene, which cannot sustain the diagnosis except for the RKAR1A gene sequencing for analysis.

Ferreira SH, Costa MM, Rios E, et al.
Carney complex due to a novel pathogenic variant in the PRKAR1A gene - a case report.
J Pediatr Endocrinol Metab. 2019; 32(2):197-202 [PubMed] Related Publications
Background Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of Cushing's syndrome (CS). It may occur sporadically or as part of a familial syndrome called Carney complex (CC). It is a rare entity, with fewer than 750 cases reported. Case presentation We describe the case of a 16-year-old otherwise healthy female referred to our endocrinology department for progressive weight gain. During investigation, an adrenocorticotropic hormone (ACTH) independent CS was identified and the possibility of an adrenocortical tumor was suggested. The histological exam of the left adrenal gland was compatible with PPNAD. Genetic study identified a novel pathogenic variant in the PRKAR1A gene. Her family history was then reviewed and her father had died prematurely due to a cardiac myxoma. Besides abnormal skin pigmentation, the girl presented no other features of CC. Conclusions Careful follow-up of these patients is important to detect other manifestations of CC and to prevent life-threatening comorbidities, like cardiac myxomas or malignant diseases. Genetic counseling of the patients and their siblings is also very important.

van der Tuin K, Ventayol Garcia M, Corver WE, et al.
Targetable gene fusions identified in radioactive iodine refractory advanced thyroid carcinoma.
Eur J Endocrinol. 2019; 180(4):235-241 [PubMed] Related Publications
Objective Gene alterations leading to activation of the MAPK pathway are of interest for targeted therapy in patients with advanced radioactive iodine refractory (RAI-R) thyroid carcinoma. Due to technical reasons gene fusion analysis in RNA isolated from formalin-fixed tumor tissues has till now been limited. The objective of the present study was to identify targetable gene rearrangements in RNA isolated from formalin-fixed RAI-R thyroid carcinomas. Design Retrospective study in 132 patients with RAI-R thyroid carcinoma (59 papillary-, 24 follicular-, 35 Hürthle cell- and 14 anaplastic thyroid carcinoma). Methods Total nucleic acid (undivided DNA and RNA) was isolated from formalin-fixed tissue. Extensive gene fusion analysis was performed in all samples that tested negative for pathogenic BRAF, NRAS, HRAS and KRAS variants. Results Seven targetable gene fusions were identified in the remaining 60 samples without known DNA variants. This includes frequently reported gene fusions such as CCDC6/RET (PTC1), PRKAR1A/RET (PTC2) and ETV6/NTRK3 , and gene fusions that are less common in thyroid cancer (TPM3/NTRK1, EML4/ALK and EML4/NTRK3). Of note, most gene fusions were detected in papillary thyroid carcinoma and MAPK-associated alterations in Hürthle cell carcinomas are rare (2/35). Conclusion Targetable gene fusions were found in 12% of RAI-R thyroid carcinoma without DNA variants and can be effectively identified in formalin-fixed tissue. These gene fusions might provide a preclinical rationale to include specific kinase inhibitors in the treatment regimen for these patients. The latter intends to restore iodine transport and/or take advantage of the direct effect on tumor cell vitality once progressive disease is seen.

Kiriakopoulos A, Linos D
Carney Syndrome Presented as a Pathological Spine Fracture in a 35-Year-Old Male.
Am J Case Rep. 2018; 19:1366-1369 [PubMed] Free Access to Full Article Related Publications
BACKGROUND Carney complex (CNC) is a genetic disorder that presents as an adrenocorticotropic hormone (ACTH)-independent variant of endogenous Cushing syndrome. It was first reported in 1985 and was described as a form of multiple endocrine hyperplasia associated with mutations of the c-AMP-dependent protein kinase (PRKAR1A) gene that causes bilateral adrenal hyperplasia. We report a case of an incidentally found CNC in a 35-year-old male, and this case report focuses on the diagnostic scheme as well as the surgical treatment of this rare challenging condition. CASE REPORT A-35-year-old male presented with pathological thoracic spine fracture. The patient exhibited obesity, facial flushing, red-purplish streaks on the abdominal wall, multiple pigmented nevi of the trunk, and hypertension. Family history was positive for cardiac myxoma. Laboratory investigation showed ACTH-independent Cushing syndrome. Abdominal magnetic resonance imaging and computed tomography scan showed bilateral adrenal hyperplasia. The ensuing Liddle test revealed the characteristic paradox increase of 24-hours urine cortisol for CNC. After a bilateral retroperitoneoscopic adrenalectomy, histologic examination confirmed the presence of bilateral primary pigmented nodular adrenocortical disease (PPNAD). Genetic testing revealed a unique mutation of the responsible PRKAR1A gene. CONCLUSIONS CNC presence was suspected due to the family history. Its characteristic pathologic manifestation called PPNAD, clinically presents as an ACTH-independent Cushing syndrome with paradoxical positive response of urinary glucocorticosteroid excretion after dexamethasone administration (Liddle's test). Bilateral retroperitoneoscopic adrenalectomy constitutes an acceptable surgical option for PPNAD.

Kamilaris CDC, Faucz FR, Voutetakis A, Stratakis CA
Carney Complex.
Exp Clin Endocrinol Diabetes. 2019; 127(2-03):156-164 [PubMed] Related Publications
Carney complex is a rare, autosomal dominant, multiple endocrine neoplasia and lentiginosis syndrome, caused in most patients by defects in the

Tirosh A, Valdés N, Stratakis CA
Genetics of micronodular adrenal hyperplasia and Carney complex.
Presse Med. 2018 Jul - Aug; 47(7-8 Pt 2):e127-e137 [PubMed] Related Publications
Micronodular bilateral adrenal hyperplasia (MiBAH) is a rare cause of adrenal Cushing syndrome (CS). The investigations carried out on this disorder during the last two decades suggested that it could be divided into at least two entities: primary pigmented nodular adrenocortical disease (PPNAD) and isolated micronodular adrenocortical disease (i-MAD). The most common presentation of MiBAH is familial PPNAD as part of Carney complex (CNC) (cPPNAD). CNC, associated with multiple endocrine and non-endocrine neoplasias, was first described in 1985 in 40 patients, 10 of whom were familial cases. In 2000, we identified inactivating germline mutations of the PRKAR1A gene, encoding the regulatory subunit type 1α (RIα) of protein kinase A (PKA), in the majority of patients with CNC and PPNAD. PRKAR1A mutations causing CNC lead to increased PKA activity. Since then, additional genetic alterations in the cAMP/PKA signaling pathway leading to increased PKA activity have been described in association with MiBAH. This review summarizes older and recent findings on the genetics and pathophysiology of MiBAH, PPNAD, and related disorders.

Albani A, Perez-Rivas LG, Reincke M, Theodoropoulou M
Endocr Pract. 2018; 24(10):907-914 [PubMed] Related Publications
OBJECTIVE: Cushing disease is a rare severe condition caused by pituitary tumors that secrete adrenocorticotropic hormone (ACTH), leading to excessive endogenous glucocorticoid production. Tumors causing Cushing disease, also called corticotropinomas, are typically monoclonal neoplasms that mainly occur sporadically.
METHODS: Literature review.
RESULTS: Cushing disease is very rarely encountered in genetic familial syndromes. Oncogenes and tumor suppressor genes commonly associated with other tumor types are only rarely mutated in this tumor type. The advent of next-generation sequencing led to the identification of a single mutational hotspot in the ubiquitin-specific protease 8 ( USP8) gene in almost half of Cushing disease tumors.
CONCLUSION: The new discoveries showcase a novel mechanism responsible for corticotroph tumorigenesis and ACTH hypersecretion and highlight USP8 and its downstream signaling pathways as potential promising pharmacologic targets for the management of Cushing disease.
ABBREVIATIONS: ACTH = adrenocorticotropic hormone; BRG1 = Brahma-related gene 1; CABLES1 = CDK5 and ABL1 enzyme substrate 1; CD = Cushing disease; CNC = Carney complex; DICER1 = cytoplasmic endoribonuclease III; EGFR = epidermal growth factor receptor; GR = glucocorticoid receptor; IL = interleukin; MEN = multiple endocrine neoplasia; miRNA = microRNA; POMC = proopiomelanocortin; SSTR = somatostatin receptor; USP8 = ubiquitin-specific protease 8.

Candida Barisson Villares Fragoso M, Pontes Cavalcante I, Meneses Ferreira A, et al.
Genetics of primary macronodular adrenal hyperplasia.
Presse Med. 2018 Jul - Aug; 47(7-8 Pt 2):e139-e149 [PubMed] Related Publications
Recent advances in molecular genetics investigations of primary macronodular adrenal hyperplasia (PMAH) have been providing new insights for the research on this issue. The cAMP-dependent pathway is physiologically triggered by ACTH and its receptor, MC2-R, in adrenocortical cells. Different mechanisms of this cascade may be altered in some functioning adrenal cortical disorders. Activating somatic mutations of the GNAS gene (known as gsp oncogene) which encodes the stimulatory G protein alpha-subunit (Gsα) have been found in a small number of adrenocortical secreting adenomas and rarely in PMAH. Lately, ARMC5 was linked to the cyclic AMP signaling pathway, which could be implicated in all of mechanisms of cortisol-secreting by macronodules adrenal hyperplasia and the molecular defects in: G protein aberrant receptors; MC2R; GNAS; PRKAR1A; PDE11A; PDE8B. Around 50 % of patient's relatives with PMAH and 30 % of apparently sporadic hypercortisolism carried ARMC5 mutations. Therefore, PMAH is genetically determined more frequently than previously believed. This review summarizes the most important molecular mechanisms involved in PMAH.

Michot C, Le Goff C, Blair E, et al.
Expanding the phenotypic spectrum of variants in PDE4D/PRKAR1A: from acrodysostosis to acroscyphodysplasia.
Eur J Hum Genet. 2018; 26(11):1611-1622 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Acrodysostosis (MIM 101800) is a dominantly inherited condition associating (1) skeletal features (short stature, facial dysostosis, and brachydactyly with cone-shaped epiphyses), (2) resistance to hormones and (3) possible intellectual disability. Acroscyphodysplasia (MIM 250215) is characterized by growth retardation, brachydactyly, and knee epiphyses embedded in cup-shaped metaphyses. We and others have identified PDE4D or PRKAR1A variants in acrodysostosis; PDE4D variants have been reported in three cases of acroscyphodysplasia. Our study aimed at reviewing the clinical and molecular findings in a cohort of 27 acrodysostosis and 5 acroscyphodysplasia cases. Among the acrodysostosis cases, we identified 9 heterozygous de novo PRKAR1A variants and 11 heterozygous PDE4D variants. The 7 patients without variants presented with symptoms of acrodysostosis (brachydactyly and cone-shaped epiphyses), but none had the characteristic facial dysostosis. In the acroscyphodysplasia cases, we identified 2 PDE4D variants. For 2 of the 3 negative cases, medical records revealed early severe infection, which has been described in some reports of acroscyphodysplasia. Subdividing our series of acrodysostosis based on the disease-causing gene, we confirmed genotype-phenotype correlations. Hormone resistance was consistently observed in patients carrying PRKAR1A variants, whereas no hormone resistance was observed in 9 patients with PDE4D variants. All patients with PDE4D variants shared characteristic facial features (midface hypoplasia with nasal hypoplasia) and some degree of intellectual disability. Our findings of PDE4D variants in two cases of acroscyphodysplasia support that PDE4D may be responsible for this severe skeletal dysplasia. We eventually emphasize the importance of some specific assessments in the long-term follow up, including cardiovascular and thromboembolic risk factors.

Cohen JN, Spies JA, Ross F, et al.
Heavily Pigmented Epithelioid Melanoma With Loss of Protein Kinase A Regulatory Subunit-α Expression.
Am J Dermatopathol. 2018; 40(12):912-916 [PubMed] Related Publications
Heavily pigmented melanocytic neoplasms are genotypically and phenotypically diverse. Recently, a subset of this histopathologic spectrum was shown to harbor recurrent genetic alterations in the gene-encoding protein kinase A regulatory subunit-α (PRKAR1A). To date, no histopathologic descriptions of melanomas arising from this pathway have been described. We present a case of a darkly pigmented papule arising on the posterior neck of a 28-year-old man. Microscopically, the heavily pigmented compound melanocytic proliferation was centered in the dermis with permeation into the superficial subcutis. Tumor cells were arranged in large confluent nests and fascicles and lacked maturation with descent. The epithelioid melanocytes were characterized by enlarged vesicular nuclei with prominent nucleoli, nuclear pleomorphism, and plentiful gray-brown granular cytoplasm. Mitotic figures were readily identified. By immunohistochemistry, melanocytes were positive for mutant BRAF V600E and showed loss of Prkar1α and p16 expression. A multiplex MART-1/tyrosinase/phosophohistone-H3 immunostain demonstrated an increased mitotic index in melanocytes. The combination of highly atypical cytomorphology and architecture, increased mitoses, and p16 expression loss compelled the diagnosis of melanoma. Overall, we present the first clinicopathologic description of a PRKAR1A-inactivated melanoma to highlight morphological features and discuss mimics that may enter the differential diagnosis.

Graham RP
Fibrolamellar Carcinoma: What Is New and Why It Matters.
Surg Pathol Clin. 2018; 11(2):377-387 [PubMed] Related Publications
Fibrolamellar carcinoma is distinctive at clinical and histologic levels. A novel DNAJB1-PRKACA fusion gene characterizes almost all cases, distinguishes it from other hepatocellular neoplasms, and drives the pathogenesis of this unique tumor. A subset of cases of fibrolamellar carcinoma is associated with alternate mechanisms of protein kinase A activation. This review article discusses common and unusual histologic features of fibrolamellar carcinoma, its differential diagnoses, and how to make the diagnosis while avoiding key pitfalls. The impact of the discovery of the fusion gene on the understanding of the tumor and the prognosis of fibrolamellar carcinoma are also discussed.

Wang L, Wang Q, Zhou Y, et al.
Recurrent left atrial myxoma in Carney complex: A case report of a familial pedigree.
Medicine (Baltimore). 2018; 97(12):e0247 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
RATIONALE: Carney complex (CNC) accounts for up to two-thirds of familial cardiac myxoma, which is a rare autosomal dominant syndrome characterized by multiple mucocutaneous lesions and endocrine tumors. Mutation in the cAMP-dependent protein kinase A (PKA) regulatory (R) subunit 1 (PRKAR1A) gene has been identified as a cause of CNC. In this article, we report 3 first-degree relatives with cardiac myxoma who were diagnosed with CNC and underwent surgical resection.
PRESENTING CONCERNS: The recurrence of cardiac myxoma was detected in a 45-year-old male by echocardiography 5 years after the resection was carried out, without any additional symptoms. Family screening indicated that his brother and his brother's son also had a history of cardiac myxoma.
DIAGNOSIS: The echocardiography of the patient showed a 43 mm × 28 mm echo mass at the bottom of the atrial septum near anterior mitral leaflet. Sequencing of the patient's genomic DNA obtained from peripheral blood identified a p.E17X (c.491-492delTG) mutation in PRKAR1A, which encodes the type Iα regulatory subunit of protein kinase A.
INTERVENTIONS: The patient received redo cardiac myxoma resection and mitral valve repair under cardiopulmonary bypass. Echocardiographic surveillance was conducted after the surgery.
OUTCOMES: The patient recovered quickly after the surgery and was discharged without any abnormality detected by echocardiography. Follow-up after 1 year showed no recurrence of the cardiac myxoma.
MAIN LESSON: We recommend echocardiographic surveillance of the affected individuals and their first-degree relatives at regular intervals, given the high risk of recurrence and the morbidity and mortality associated with cardiac tumors in any location.

Lim CT, Korbonits M
Endocr Pract. 2018; 24(5):473-488 [PubMed] Related Publications
OBJECTIVE: Pituitary adenomas are the third most common central nervous system tumors and arise from the anterior pituitary within the pituitary fossa.
METHODS: Literature review and discussion.
RESULTS: The signs and symptoms of patients with pituitary adenomas vary from 'mass effects' caused by a large adenoma to features secondary to excess pituitary hormones produced by the functioning pituitary adenoma. Detailed histopathologic assessment, based on novel classifications and the latest World Health Organization guidelines, helps to categorize pituitary adenomas into different subtypes and identify features that, in some cases, help to predict their behavior. Most of the pituitary tumors occur sporadically without known genetic predisposition, but in a significant minority of cases, somatic mutations can be identified in the GNAS and USP8 genes. A small proportion of the cases have germline genetic defects or embryonic mutations leading to mosaicism. Genes with germ-line mutations predisposing to pituitary adenomas include AIP, GPR101, MEN1, CDKN1B, PRKAR1A, PRKAR2A, DICER1, NF1, and SDHx, whereas more recently, CABLES1 has also been implicated.
CONCLUSION: Understanding the pathogenesis of pituitary adenomas will allow clinicians to correlate the pathologic and genetic features with clinical data, helping decisions on the best management of these tumors.
ABBREVIATIONS: ACTH = adrenocorticotropic hormone; AIP = aryl hydrocarbon receptor-interacting protein; αSU = alpha-subunit; EGFR = epithelial growth factor receptor; ER = estrogen receptor; FSH = follicle-stimulating hormone; GH = growth hormone; GHRH = growth hormone-releasing hormone; IGF-1 = insulin-like growth factor 1; LH = luteinizing hormone; MEN1 = multiple endocrine neoplasia 1; MRI = magnetic resonance imaging; NFPA = nonfunctioning pituitary adenoma; PRL = prolactin; TSH = thyroid-stimulating hormone; USP8 = ubiquitin-specific peptidase 8; WHO = World Health Organization.

Liu Q, Tong D, Liu G, et al.
Carney complex with PRKAR1A gene mutation: A case report and literature review.
Medicine (Baltimore). 2017; 96(50):e8999 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
RATIONALE: Carney complex (CNC) is a multiple neoplasia syndrome with autosomal dominant inheritance. CNC is characterized by the presence of myxomas, spotty skin pigmentation, and endocrine overactivity. No direct correlation has been established between disease-causing mutations and phenotype.
PATIENT CONCERNS: A 16-year-old boy was admitted because of excessive weight gain over 3 years and purple striae for 1 year. Physical examination revealed Cushingoid features and spotty skin pigmentation on his face, lip, and sclera.
DIAGNOSES: The patient was diagnosed as Carney complex.
INTERVENTIONS: the patient underwent right adrenalectomy and partial adrenalectomy of the left adrenal gland.
OUTCOME: Results of imaging showed bilateral adrenal nodular hyperplasia, multiple microcalcifications of the bilateral testes, and compression fracture of the thoracolumbar spine. Histopathological results confirmed multiple pigmented nodules in the adrenal glands. DNA sequencing revealed a nonsense mutation in the gene encoding regulatory subunit type 1-alpha of protein kinase A (PRKAR1A; c.205C > T). After the second adrenalectomy, the Cushingoid features disappeared, and cortisol levels returned to normal.
LESSONS: Carney complex is a rare disease that lacks consistent genotype-phenotype correlations. Our patient, who carried a germline PRKAR1A nonsense mutation (c.205C > T), clinical features included spotty skin pigmentation, osteoporosis, and primary pigmented nodular adrenal disease. Adrenalectomy is the preferred treatment for Cushing syndrome due to primary pigmented nodular adrenal disease.

Schaefer IM, Hornick JL, Bovée JVMG
The role of metabolic enzymes in mesenchymal tumors and tumor syndromes: genetics, pathology, and molecular mechanisms.
Lab Invest. 2018; 98(4):414-426 [PubMed] Related Publications
The discovery of mutations in genes encoding the metabolic enzymes isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), and fumarate hydratase (FH) has expanded our understanding not only of altered metabolic pathways but also epigenetic dysregulation in cancer. IDH1/2 mutations occur in enchondromas and chondrosarcomas in patients with the non-hereditary enchondromatosis syndromes Ollier disease and Maffucci syndrome and in sporadic tumors. IDH1/2 mutations result in excess production of the oncometabolite (D)-2-hydroxyglutarate. In contrast, SDH and FH act as tumor suppressors and genomic inactivation results in succinate and fumarate accumulation, respectively. SDH deficiency may result from germline SDHA, SDHB, SDHC, or SDHD mutations and is found in autosomal-dominant familial paraganglioma/pheochromocytoma and Carney-Stratakis syndrome, describing the combination of paraganglioma and gastrointestinal stromal tumor (GIST). In contrast, patients with the non-hereditary Carney triad, including paraganglioma, GIST, and pulmonary chondroma, usually lack germline SDH mutations and instead show epigenetic SDH complex inactivation through SDHC promoter methylation. Inactivating FH germline mutations are found in patients with hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome comprising benign cutaneous/uterine leiomyomas and renal cell carcinoma. Mutant IDH, SDH, and FH share common inhibition of α-ketoglutarate-dependent oxygenases such as the TET family of 5-methylcytosine hydroxylases preventing DNA demethylation, and Jumonji domain histone demethylases increasing histone methylation, which together inhibit cell differentiation. Ongoing studies aim to better characterize these complex alterations in cancer, the different clinical phenotypes, and variable penetrance of inherited and sporadic cancer predisposition syndromes. A better understanding of the roles of metabolic enzymes in cancer may foster the development of therapies that specifically target functional alterations in tumor cells in the future. Here, the physiologic functions of these metabolic enzymes, the mutational spectrum, and associated functional alterations will be discussed, with a focus on mesenchymal tumor predisposition syndromes.

Rosenbaum JN, Bloom R, Forys JT, et al.
Genomic heterogeneity of ALK fusion breakpoints in non-small-cell lung cancer.
Mod Pathol. 2018; 31(5):791-808 [PubMed] Related Publications
In lung adenocarcinoma, canonical EML4-ALK inversion results in a fusion protein with a constitutively active ALK kinase domain. Evidence of ALK rearrangement occurs in a minority (2-7%) of lung adenocarcinoma, and only ~60% of these patients will respond to targeted ALK inhibition by drugs such as crizotinib and ceritinib. Clinically, targeted anti-ALK therapy is often initiated based on evidence of an ALK genomic rearrangement detected by fluorescence in situ hybridization (FISH) of interphase cells in formalin-fixed, paraffin-embedded tissue sections. At the genomic level, however, ALK rearrangements are heterogeneous, with multiple potential breakpoints in EML4, and alternate fusion partners. Using next-generation sequencing of DNA and RNA together with ALK immunohistochemistry, we comprehensively characterized genomic breakpoints in 33 FISH-positive lung adenocarcinomas. Of these 33 cases, 29 (88%) had detectable DNA level ALK rearrangements involving EML4, KIF5B, or non-canonical partners including ASXL2, ATP6V1B1, PRKAR1A, and SPDYA. A subset of 12 cases had material available for RNA-Seq. Of these, eight of eight (100%) cases with DNA rearrangements showed ALK fusion transcripts from RNA-Seq; three of four cases (75%) without detectable DNA rearrangements were similarly negative by RNA-Seq, and one case was positive by RNA-Seq but negative by DNA next-generation sequencing. By immunohistochemistry, 17 of 19 (89%) tested cases were clearly positive for ALK protein expression; the remaining cases had no detectable DNA level rearrangement or had a non-canonical rearrangement not predicted to form a fusion protein. Survival analysis of patients treated with targeted ALK inhibitors demonstrates a significant difference in mean survival between patients with next-generation sequencing confirmed EML4-ALK rearrangements, and those without (20.6 months vs 5.4 months, P<0.01). Together, these data demonstrate abundant genomic heterogeneity among ALK-rearranged lung adenocarcinoma, which may account for differences in treatment response with targeted ALK inhibitors.

Fu J, Lai F, Chen Y, et al.
A novel splice site mutation of the PRKAR1A gene, C.440+5 G>C, in a Chinese family with Carney complex.
J Endocrinol Invest. 2018; 41(8):909-917 [PubMed] Related Publications
BACKGROUND: Carney complex (CNC) is an extremely rare, multiple endocrine neoplasia syndrome that occurs in an autosomal dominant manner. Mutations in PRKAR1A have been reported to be a common genetic cause of CNC.
METHODS: In this study, we reported a Chinese pedigree of CNC that manifests mainly as spotty skin pigmentation and primary pigmented nodular adrenocortical disease. Whole blood samples of this pedigree were collected for DNA/RNA analysis. Polymerase chain reaction (PCR) and reverse-transcription polymerase chain reaction analyses were performed to amplify the 11 exons and adjacent introns of PRKAR1A. Direct sequencing was used to detect the mutation, and DNA from 70 Han Chinese people was extracted and sequenced as a control to estimate the frequency of the identified mutation.
RESULTS: Within the pedigree, ten patients with CNC were identified, and a novel heterozygous mutation (c.440+5 G>C in intron 4a) was identified in the PRKAR1A gene. PCR amplification of cDNA from the control subjects and patients was performed. Agarose gel electrophoresis showed only one wild-type band in the cDNA corresponding to the former group, whereas an extra band was present in samples from the latter group corresponding to the skipping of exon 4a; this confirms that the variant affects PRKAR1A splicing.
CONCLUSION: In conclusion, the c.440+5 G>C mutation is a new splice site mutation that has not been reported and has the potential to broaden the mutational spectrum of PRKAR1A that is associated with CNC, which would facilitate genetic diagnosis and counseling for CNC.

Bonnet-Serrano F, Bertherat J
Genetics of tumors of the adrenal cortex.
Endocr Relat Cancer. 2018; 25(3):R131-R152 [PubMed] Related Publications
This review describes the molecular alterations observed in the various types of tumors of the adrenal cortex, excluding Conn adenomas, especially the alterations identified by genomic approaches these last five years. Two main forms of bilateral adrenocortical tumors can be distinguished according to size and aspect of the nodules: primary pigmented nodular adrenal disease (PPNAD), which can be sporadic or part of Carney complex and primary bilateral macro nodular adrenal hyperplasia (PBMAH). The bilateral nature of the tumors suggests the existence of an underlying genetic predisposition. PPNAD and Carney complex are mainly due to germline-inactivating mutations of

Graham RP, Lackner C, Terracciano L, et al.
Fibrolamellar carcinoma in the Carney complex: PRKAR1A loss instead of the classic DNAJB1-PRKACA fusion.
Hepatology. 2018; 68(4):1441-1447 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Fibrolamellar carcinomas are characterized by activation of protein kinase A, a kinase composed of catalytic and regulatory subunits. PRKACA encodes a catalytic subunit of protein kinase A, and almost all fibrolamellar carcinomas have a heterozygous 400-kb deletion that leads to the fusion of DNAJB1 and PRKACA. The resulting DNAJB1-PRKACA fusion transcript is believed to activate protein kinase A by dysregulation of the catalytic portion of the protein. In contrast, PRKAR1A encodes one of the regulatory subunits of protein kinase A. We hypothesized that loss of function of this regulatory unit could also lead to protein kinase A activation and thus to fibrolamellar carcinoma. Because PRKAR1A mutations underlie the Carney complex, we searched for liver tumors in individuals with the Carney complex. We identified 3 individuals with fibrolamellar carcinomas and a personal history of the Carney complex. All three tumors displayed the typical morphology of fibrolamellar carcinoma and were positive for arginase, cytokeratin 7, and cluster of differentiation 68. Fluorescence in situ hybridization was negative for PRKACA rearrangements. However, PRKAR1A sequencing identified pathogenic mutations in two of two cases with successful sequencing. In addition, all three cases were negative for PRKAR1A protein expression, consistent with inactivation of this key regulatory unit of protein kinase A. We also identified one additional fibrolamellar carcinoma in an individual without a documented history of the Carney complex who was negative for PRKACA rearrangements but had loss of PRKAR1A protein expression as well as PRKAR1A mutations.
CONCLUSION: Fibrolamellar carcinoma can be part of the Carney complex; in this setting, fibrolamellar carcinomas have inactivating PRKAR1A mutations instead of the DNAJB1-PRKACA fusion gene found in sporadic fibrolamellar carcinomas, providing an alternate means for activation of protein kinase A. (Hepatology 2017).

Bosco Schamun MB, Correa R, Graffigna P, et al.
Carney complex review: Genetic features.
Endocrinol Diabetes Nutr. 2018; 65(1):52-59 [PubMed] Related Publications
Carney complex is a multiple neoplasia syndrome having endocrine and non-endocrine manifestations. Diagnostic criteria include myxoma, lentigines, and primary pigmented nodular adrenocortical disease, amongst other signs/symptoms. In most cases it is an autosomal dominant disease, and diagnosis therefore requires study and follow-up of the family members. Inactivating mutations of the PRKAR1A gene were identified as the main cause of the disease, although since 2015 other disease-related genes, including PRKACA and PRKACB activating mutations, have also been related with Carney complex. This review will address the genetic aspects related to Carney complex.

Malicka JE, Świrska J, Kurowska M, et al.
Familial isolated pituitary adenomas (FIPA). Case report of four families and review of literature.
Endokrynol Pol. 2017; 68(6):697-707 [PubMed] Related Publications
Background The majority of pituitary adenomas are sporadic, but about 5% of them occur in a familial setting, predominantly in multiple endocrine neoplasia type 1 and Carney complex. Familial isolated pituitary adenomas (FIPA), unrelated to the syndromes mentioned above, were also described. The clinical course of FIPA differs significantly from sporadic cases, and is characterized by a larger tumor size, more aggressive course and younger patients' age at the moment of recognition. Objectives The aim of this retrospective study is to present 4 families in which two closely related people were diagnosed with pituitary adenomas. Probably these cases are clinical manifestations of FIPA. Material and methods Eight patients within four families, presenting with anterior pituitary tumors were described. The authors analyzed medical and family histories of the patients, their imaging pictures (pituitary MRI/CT) and hormonal tests. Results Family 1.: two sisters with acromegaly in the course of macroadenoma. Family 2.: two brothers with clinically nonsecreting macroadenomas. Family 3.: father and daughter with clinically nonsecreting macroadenomas. Family 4.: young man with acromegaly caused by macroadenoma and a daughter of his mother`s sister with microprolactinoma.
CONCLUSIONS: Familial isolated pituitary adenomas are more common than it was previously thought, therefore, specific questioning regarding family history should be a part of the workup of all patients with pituitary adenomas. Genetically induced pituitary tumors often have aggressive behavior in terms of tumor expansion and resistance to different treatment options and often involve a multidisciplinary approach that combines endocrine, neurosurgical, and radiological specialists.

Stelmachowska-Banas M, Zgliczynski W, Tutka P, et al.
Fatal Carney Complex in Siblings Due to De Novo Large Gene Deletion.
J Clin Endocrinol Metab. 2017; 102(11):3924-3927 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
Context: Carney complex (CNC) is a rare multiple neoplasia syndrome involving cardiac, endocrine, neural, and cutaneous tumors and a variety of pigmented skin lesions. CNC can be inherited as an autosomal dominant trait, but in about one-third of patients, the disease is caused by de novo mutation in the PRKAR1A gene localized on chromosome 17q22-24. Most of the mutations include single base substitutions and small deletions/insertions not exceeding 15 base pairs. Recently, large germline PRKAR1A deletions have been described and may cause a more severe phenotype.
Case Description: Herein, we report the cases of two siblings with CNC with a de novo large deletion of 107 kb at 17q24.2 associated with acromegaly in both and primary pigmented nodular adrenocortical disease, cardiac myxoma, and lethal metastatic melanotic schwannian tumor at the age of 27 years in one of them, supporting the hypothesis that large deletions of PRKAR1A lead to severe disease.
Conclusions: To our knowledge, this is the first description of familial CNC in siblings in which neither parent carried the deletion in blood-derived DNA, suggesting that one of them had germ cell mosaicism for this deletion. Testing for large gene deletions should be obtained in all patients who meet the diagnostic criteria for CNC but do not have a PRKAR1A mutation by Sanger sequencing.

Akin S, Noyan S, Dagdelen S, et al.
Unusual presentations of Carney Complex in patient with a novel PRKAR1A mutation.
Neuro Endocrinol Lett. 2017; 38(4):248-254 [PubMed] Related Publications
Carney Complex (CNC) is a multiple neoplasia syndrome characterized by skin tumors and pigmented lesions, myxomas, and various endocrine tumors. The aim of this case report was to describe a case of CNC with a novel PRKAR1A mutation. A man aged 46 years with a medical history of surgery for cardiac myxomas at the age of 39 was admitted to our hospital because of four newly-developed heart masses. The histologic examination confirmed cardiac myxomas. He had many presentations of CNC such as growth hormone (GH) and prolactin (PRL)-secreting mixed pituitary adenoma, benign thyroid nodule, large-cell calcifying Sertoli cell tumor (LCCST), and superficial angiomyxoma. A bilateral adrenalectomy was performed because the laboratory findings suggested primary pigmented nodular adrenocortical disease (PPNAD). The pathologic examination revealed a focal unilateral PPNAD, unilateral nonpigmented adrenocortical nodule, and bilateral adrenal medullary hyperplasia. Two years after the second cardiac operation, an interatrial septum-derived tumor was detected. An atrial myxoma was confirmed with histologic studies. Based on these findings, the patient was confirmed to have CNC. A novel insertion mutation in the type 1A regulatory subunit of the cAMP-dependent protein kinase A gene (PRKAR1A) in exon 2 was detected in our patient through genetic analysis. The presence of multiple myxomas and endocrine abnormalities should be an indication to physicians to further investigate for CNC. Herein, we described a case of CNC with a novel mutation in exon 2 of the PRKAR1A gene with typical and atypical clinical features.

Cohen JN, Joseph NM, North JP, et al.
Genomic Analysis of Pigmented Epithelioid Melanocytomas Reveals Recurrent Alterations in PRKAR1A, and PRKCA Genes.
Am J Surg Pathol. 2017; 41(10):1333-1346 [PubMed] Related Publications
Pigmented epithelioid melanocytoma (PEM) is a rare cutaneous melanocytic tumor first described as epithelioid blue nevus in patients with the Carney Complex (CC). PEM was among the first established examples of an intermediate class of melanocytic tumors, including atypical Spitz tumors, with frequent metastasis to lymph nodes but only rare extranodal spread. Sporadic and CC-associated PEM are essentially histologically indistinguishable. A subset of PEM shows loss of cytoplasmic expression of the protein kinase A regulatory subunit alpha (PRKAR1A), a tumor suppressor gene mutated in 70% of families with CC. However, molecular studies of such tumors have been limited. Therefore, we used next-generation sequencing to assess 480 cancer-related genes and performed PrkaR1α immunohistochemistry on 13 cases morphologically consistent with PEM. Six cases demonstrated loss of PrkaR1α expression by immunohistochemistry. Three cases were "combined" PEM arising in association with a common nevus. These lesions harbored PRKAR1A genetic alterations in addition to BRAF mutations. Three "pure" PEM, not associated with a common nevus, showed no evidence of PRKAR1A genetic alterations despite loss of PrkaR1α expression. Two of these PEM demonstrated MAP2K1 in frame deletions. PrkaR1α protein expression was preserved in 7 cases. Two of these lesions revealed fusions of the gene encoding the protein kinase C alpha isoform (PRKCA) to 2 distinct partners (ATP2B4-PRKCA and RNF13-PRKCA). Two lesions may represent misdiagnosed "blue nevus with epithelioid features" as they demonstrated GNAQ hotspot mutations. A conceivable explanation, but one we do not favor is that rare PEM are caused by GNAQ mutations. No genetic aberrations were detected in 3 lesions. None of our 13 cases demonstrated TERT alterations or significant chromosomal copy number changes. These results further validate the concept of PEM as a distinctive intermediate/borderline melanocytic tumor, and also illustrate its molecular heterogeneity.

Kiefer FW, Winhofer Y, Iacovazzo D, et al.
Eur J Endocrinol. 2017; 177(2):K7-K12 [PubMed] Related Publications
CONTEXT: Carney complex (CNC) is an autosomal dominant condition caused, in most cases, by an inactivating mutation of the
CASE DESCRIPTION: Here, we describe the first case of a patient with CNC and adrenocorticotropic hormone (ACTH)-dependent Cushing disease due to a pituitary corticotroph adenoma. Loss-of-heterozygosity analysis of the pituitary tumour revealed loss of the wild-type copy of

Lozada JR, Burke KA, Maguire A, et al.
Myxoid fibroadenomas differ from conventional fibroadenomas: a hypothesis-generating study.
Histopathology. 2017; 71(4):626-634 [PubMed] Article available free on PMC after 01/11/2019 Related Publications
AIMS: Breast myxoid fibroadenomas (MFAs) are characterized by a distinctive hypocellular myxoid stroma, and occur sporadically or in the context of Carney complex, an inheritable condition caused by PRKAR1A-inactivating germline mutations. Conventional fibroadenomas (FAs) are underpinned by recurrent MED12 mutations in the stromal components of the lesions. The aim of this study was to investigate the genomic landscape of MFAs and compare it with that of conventional FAs.
METHODS AND RESULTS: Eleven MFAs from patients without clinical and/or genetic evidence of Carney complex were retrieved. DNA samples of tumour and matching normal tissue were subjected to massively parallel sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay, an assay targeting 410 cancer genes. Genetic alterations detected by MSK-IMPACT were tested in samples in which the stromal and epithelial components were separately laser capture-microdissected. Sequencing revealed no germline PRKAR1A mutations and non-synonymous mutations in six MFAs. Interestingly, in three of the MFAs in which the stromal and epithelial components were separately microdissected, the mutations were found to be restricted to the epithelial rather than the stromal component. The sole exception was a lesion harbouring a somatic truncating PRKAR1A mutation. Upon histological re-review, this case was reclassified as a breast myxoma, consistent with the spectrum of tumous observed in Carney complex patients. In this case, the PRKAR1A somatic mutation was restricted to the stromal component.
CONCLUSION: MFAs lack MED12 mutations, and their stromal components seem not to harbour mutations in the 410 cancer genes tested. Whole-exome and/or whole-genome analyses of MFAs are required to elucidate their genetic drivers.

Shaid M, Korbonits M
Genetics of pituitary adenomas.
Neurol India. 2017 May-Jun; 65(3):577-587 [PubMed] Related Publications
Clinically relevant pituitary tumors presenting with altered hormonal secretion or mass effect represent a significant proportion of patients in endocrinology clinics. However, in recent years, these patients are also referred to clinical genetic services due to possible germline mutations causing syndromic or isolated pituitary adenomas. While somatic mutations have been identified in GNAS, USB8, PIK3CA, GPR101 and rarely in RAS, germline mutations have been identified in MEN1, cyclin dependent kinase inhibitor genes, AIP, DICER1, PRKAR1A, PRKACA, SDH genes and GPR101. In this review, we present a short overview of pituitary adenoma classifications, pituitary development and somatic and germline genetic changes identified in these adenomas.

Marques P, Korbonits M
Genetic Aspects of Pituitary Adenomas.
Endocrinol Metab Clin North Am. 2017; 46(2):335-374 [PubMed] Related Publications
Although most of pituitary adenomas are benign, they may cause significant burden to patients. Sporadic adenomas represent the vast majority of the cases, where recognized somatic mutations (eg, GNAS or USP8), as well as altered gene-expression profile often affecting cell cycle proteins have been identified. More rarely, germline mutations predisposing to pituitary adenomas -as part of a syndrome (eg, MEN1 or Carney complex), or isolated to the pituitary (AIP or GPR101) can be identified. These alterations influence the biological behavior, clinical presentations and therapeutic responses, and their full understanding helps to provide appropriate care for these patients.

Bax MJ, Brown MD, Rothberg PG, et al.
Pigmented epithelioid melanocytoma (animal-type melanoma): An institutional experience.
J Am Acad Dermatol. 2017; 77(2):328-332 [PubMed] Related Publications
BACKGROUND: Pigmented epithelioid melanocytoma (PEM) is an uncommon, recently described entity with unknown biologic behavior. There is a high rate of regional metastases, but limited evidence of distant metastases or disease-related death.
OBJECTIVE: We sought to report our series of patients given a diagnosis of PEM at our institution and provide mutational analysis of genes commonly implicated in melanoma in 2 cases.
METHODS: The pathology database was queried for cases of PEM diagnosed at the University of Rochester. Charts were reviewed for follow-up information. Mutational analysis of melanoma-associated genes was performed on 2 cases.
RESULTS: Nine cases of PEM were retrieved in a 10-year retrospective review. Five patients underwent sentinel lymph node biopsy with 3 of 5 having a positive sentinel lymph node. All 9 patients are alive and disease-free with average follow-up of 38.75 months. Two tumors were tested for common melanoma-associated mutations, and were negative, except for a telomerase reverse transcriptase promoter deletion detected in 1 sample. The deletion has not been associated with melanoma, and therefore its biologic significance is unclear.
LIMITATIONS: Small sample size, retrospective nature, and single institution experience are limitations.
CONCLUSIONS: PEM appears to have an indolent behavior. However, currently the evidence is too limited to provide insight into its true biologic potential.

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