Peutz-Jeghers syndrome (PJS) is an autosomal-dominant condition characterized by the gastrointestinal polyposis, mucocutaneous pigmentation, and predisposition to a range of epithelial cancers: including colorectal, gastric, pancreatic, breast, and ovarian cancers. Women also have increased risk of sex cord tumors with annular tubules. Approximately 45% of affected individuals have no family history of PJS. (GeneReviews)
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Mutated Genes and Abnormal Protein Expression (4)
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|STK11 ||19p13.3 ||PJS, LKB1, hLKB1 ||Germline ||-STK11 mutations in Peutz-Jeghers Syndrome || 397|
|BMPR1A ||10q23.2 ||ALK3, SKR5, CD292, ACVRLK3, 10q23del || ||-BMPR1A and Peutz-Jeghers Syndrome || 10|
|PTPRH ||19q13.42 ||SAP1, R-PTP-H || ||-PTPRH and Peutz-Jeghers Syndrome || 2|
|PRSS1 ||7q34 ||TRP1, TRY1, TRY4, TRYP1 || ||-PRSS1 and Peutz-Jeghers Syndrome || 2|
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
Jiang YL, Zhao ZY, Li BR, et al.STK11 gene analysis reveals a significant number of splice mutations in Chinese PJS patients.
Cancer Genet. 2019; 230:47-57 [PubMed
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BACKGROUND: The combination of direct sequencing and multiple ligation-dependent probe amplification (MLPA) has resulted in an 80% detection rate of serine/threonine kinase 11 (STK11) gene mutations in Peutz-Jeghers syndrome (PJS); however, this rate varies in different ethnicities.
AIMS: To test the efficacy of the combination in Chinese patients with PJS.
METHODS: PJS probands visiting our center during one year were enrolled. Sanger sequencing and MLPA were used to detect STK11 mutations. Associations between the occurrence of severe complications and risk factors were analyzed statistically.
RESULTS: We identified 47 PJS probands. Among them, 34 received an STK11 mutation test, revealing 23 point mutations and 2 exonic deletions. Nine of the mutations were splicing errors, reflecting a significantly higher proportion (p < 0.05). Laparotomy history existed for 33 of the probands, and seven families had a history of cancer. Statistical analysis revealed no associations between the occurrence of severe complications or cancers and risk factors.
CONCLUSION: The strategy achieved a high detection rate in Chinese people, validating its effectiveness. This cohort comprised a significantly higher proportion of splicing errors, reflecting the unique genetic characteristics Chinese people. No specific genotype-phenotype relationship was noted, while the wide usage of enteroscopy would benefit PJS surveillance.
BACKGROUND: Peutz-Jeghers syndrome (PJS) is caused by mutations in serine/threonine kinase 11 (STK11) gene. The increased cancer risk has been connected to P53 pathway.
METHODS: PJS probands with STK11 mutation were included in the function analysis. P53 activity elevated by STK11 mutants was investigated using dual-luciferase reporter assay in vitro after constructing expression vectors of STK11 wild type and mutants generated by site-directed substitution. The association between the P53 activity and clinicopathological factors was analysis, especially the cancer history.
RESULTS: Thirteen probands with STK11 mutations were involved, and within the mutations, c.G924A was novel. P53 activity elevation caused by 6 truncating mutations were significantly lower than that of STK11 wild type (P < 0.05). Family history of cancer was observed in 5 families. Within them, P53 activity was reduced and cancer occurred before 40 in 2 families, while it was not significantly changed and cancers happened after 45 in the other 3 families.
CONCLUSIONS: The affected P53 activity caused by STK11 mutations in PJS patients is significantly associated with protein truncation, while cancer risk in PJS can be elevated through pathways rather than P53 pathway. P53 activity test is probably a useful supporting method to predict cancer risk in PJS, which could be helpful in clinical practice.
Poffenberger MC, Metcalfe-Roach A, Aguilar E, et al.LKB1 deficiency in T cells promotes the development of gastrointestinal polyposis.
Science. 2018; 361(6400):406-411 [PubMed
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Germline mutations in
Butel-Simoes GI, Spigelman AD, Scott RJ, Vilain RELow-level parental mosaicism in an apparent de novo case of Peutz-Jeghers syndrome.
Fam Cancer. 2019; 18(1):109-112 [PubMed
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We report the case of a female found to have mosaicism for mutation in the STK11 gene, with the mutant allele expressed in her gametes, evident by her affected offspring, and in her gastrointestinal tract demonstrated on an excised polyp analysed for diagnosis. Mosaicism for Peutz-Jeghers syndrome (PJS) has been reported in a small number of cases previously but a clinical presentation such as this has not previously been described. This finding of mosaicism was several years after initial investigations failed to identify the same STK11 mutation in this woman whose son was diagnosed with PJS at a young age. This case highlights the importance of considering mosaicism as an explanation for apparent de novo cases of PJS syndrome. It also has implications for genetic counselling, predictive testing and cancer screening.
BACKGROUND: Peutz-Jeghers Syndrome (PJS) is a hereditary cancer predisposing syndrome caused by autosomal dominant mutations in the serine/threonine kinase 11 (STK11) gene and is associated with decreased life expectancy. Many families experience a poorer quality of life due to the psychological burden associated with the carrier status of their child. Therefore early genetic testing and confirmation of the diagnosis is important for patients' psychological status, as well as for clinical management, genetic counseling and possible prenatal family planning.
METHODS: In this study, peripheral blood genomic DNA samples from a Chinese PJS family with a high cancer risk were examined for STK11 mutations using Sanger sequencing and MLPA analysis. Furthermore, prenatal PJS testing from transabdominal chorionic villi sample was performed in one female member of the family. This family was followed up for three years.
RESULTS: In this family, the STK11 exon 1 deletion (c.-1114-?_290 +?del) was predicted to affect the kinase domain of the protein and co-segregated with the disease phenotype. The same mutation was detected in the fetus and genetic sequencing and MLPA of the infant's DNA and the pigmentation on his lips confirmed the result of prenatal testing. To the best of our knowledge, this is the first report on PJS prenatal diagnosis of a PJS family in China.
CONCLUSIONS: An accurate and convenient PJS prenatal testing provides an opportunity for affected families to focus on polyp-related symptoms and cancer prevention and may be helpful for couples in family planning decision-making.
Zhao ZY, Jiang YL, Li BR, et al.Close and regular surveillance is key to prevent severe complications for Peutz-Jeghers syndrome patients without gastrointestinal polyps: case report of a novel STK11 mutation (c.471_472delCT) in a Chinese girl.
BMC Surg. 2018; 18(1):24 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Peutz-Jeghers syndrome (PJS) is a Mendelian disease characterized by gastrointestinal hamartomas, mucocutaneous pigmentation (MP), and increased cancer risk. Serine/threonine kinase 11 (STK11) is the only validated causative gene in PJS. Clinical observation reveals MP and intussusception in childhood are more frequent and severe than in adults.
CASE PRESENTATION: We report here a girl without a positive family history, who grew oral and fingertip MP at her age of 2 and got abdomen dull pain from 7 years old. Endoscopy revealed no obvious polyps in the stomach or the colon until 10 years old, when she received enteroscopy. Tens of polyps were resected during enteroscopy, and pathological examination confirmed them hamartomas. A heterozygous deletion in STK11, c.471_472delCT, was detected in the proband but not in her parents, which is not recorded in databases.
CONCLUSION: The mutation we reported here is a novel one and a de-novo one, so our results enlarge the spectrum of STK11. We speculate close and regular endoscopy especially enteroscopy is necessary for complication prevention when the former endoscopy discovers no polyps temporarily in a child of suspect PJS.
Xu C, Ma Y, Cao F, et al.[Identification of a novel STK11 gene mutation in a family affected with hereditary Peutz-Jeghers syndrome].
Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2018; 35(1):89-91 [PubMed
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OBJECTIVE To explore the genetic basis for a family affected with Peutz-Jeghers syndrome (PJS). METHODS Genomic DNA was extracted from peripheral blood and oral swab samples from the patient and her relatives. Next-generation sequencing (NGS) was used to analyze 106 target genes by capturing the exons and adjacent intronic regions. Suspected pathogenic mutation was verified by NGS. RESULTS A missense STK11 mutation was detected in the proband, which was not reported previously. The mutation has caused substitution of Leucine by Proline. NGS has detected the same mutation in the mother but not among other relatives. CONCLUSION This hereditary case of PJS may be attributed to the missense mutation of the STK11 gene.
Fostira F, Mollaki V, Lypas G, et al.Genetic analysis and clinical description of Greek patients with Peutz-Jeghers syndrome: Creation of a National Registry.
Cancer Genet. 2018; 220:19-23 [PubMed
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Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder caused by germline mutations in the STK11 tumor suppressor gene. PJS patients face a cumulative cancer risk as high as 93% for all sites combined. The present study reports the spectrum of STK11 mutations in eight families with clinical diagnosis of PJS, summarizes the clinical characteristics of sixteen mutation carriers and launches a National Registry for PJS in Greece. STK11 loss-of-function (LoF) mutations were detected in 87.5% of index patients. Carriers presented with their first manifestation at a median age of 24.9 years, while early-onset breast cancer was the most frequent malignancy observed, highlighting the need for breast surveillance. Out of the deleterious STK11 mutations identified, two were novel: c.375_376delGT and c.676_679dupAACG, with 57.2% of these potentially occurring de novo. Using all available clinical and genetic data, the National Registry for Greek PJS was established in an attempt to better characterize the syndrome and raise awareness among patients and clinicians (available at https://www.peutzjeghersgreece.org). This is the first comprehensive genetic analysis and clinical characterization of Greek PJS patients, where a high incidence of breast cancer was observed and the first attempt to centralize all data in a National Registry.
RATIONALE: Peutz-Jeghers syndrome (PJS) is a Mendelian autosomal dominant disease caused by mutations in the tumor suppressor gene, serine/threonine kinase 11 (STK11). The features of this syndrome include gastrointestinal (GI) hamartomas, melanin spots on the lips and the extremities, and an increased risk of developing cancer. Early onset of disease is often characterized by mucocutaneous pigmentation and intussusception due to GI polyps in childhood.
PATIENT CONCERNS: A girl with a positive family history grew oral pigmentation at 1 and got intussusception by small bowel hamartomas at 5.
DIAGNOSES: She was diagnosed with PJS based on oral pigmentation and a positive family history of PJS.
INTERVENTIONS: Enteroscopy was employed to treat the GI polyps. Sanger sequencing was used to investigate STK11 mutation in this family.
OUTCOMES: A large jejunal polyp together with other smaller ones was resected, and the girl recovered uneventfully. We discovered a heterozygous substitution in STK11, c.A527G in exon 4, in the girl and her father who was also a PJS patient, and the amine acid change was an aspartic acid-glycine substitution in codon 176. This mutation was not found in other healthy family members and 50 unrelated non-PJS controls, and it is not recorded in databases, which prove it a novel mutation. Evolutionary conservation analysis of amino acid residues showed this aspartic acid is a conserved one between species, and protein structure prediction by SWISS-MODEL indicated an obvious change in local structure. In addition, PolyPhen-2 score for this mutation is 1, which indicates it probably damaging.
LESSONS: PJS can cause severe complication like intussusception in young children, and early screening for small bowel may be beneficial for these patients. The mutation of STK11 found in this girl is a novel one, which enlarges the spectrum of STK11. Our analysis supported it a causative one in PJS.
Ma H, Brosens LAA, Offerhaus GJA, et al.Pathology and genetics of hereditary colorectal cancer.
Pathology. 2018; 50(1):49-59 [PubMed
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Colorectal cancer (CRC) accounts for over 8% of all deaths annually worldwide. Between 2 and 5% of all CRCs occur due to inherited syndromes, including Lynch syndrome, familial adenomatous polyposis, MUTYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis and Cowden/PTEN hamartoma syndrome. In addition, serrated polyposis is a clinically defined condition characterised by multiple colorectal serrated polyps and an increased risk of CRC but the genetics are not known. In most hereditary CRC syndromes, polyps undergo carcinogenesis, but the exact route to carcinoma seems to differ between the conditions. Discovery of the key germline mutations in these syndromes has been instrumental to our understanding of the underlying molecular mechanisms of colorectal carcinogenesis. This review summarises the genetic and pathological alterations in hereditary CRC syndromes.
Zhao ZY, Jiang YL, Li BR, et al.Sanger sequencing in exonic regions of STK11 gene uncovers a novel de-novo germline mutation (c.962_963delCC) associated with Peutz-Jeghers syndrome and elevated cancer risk: case report of a Chinese patient.
BMC Med Genet. 2017; 18(1):130 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Peutz-Jeghers syndrome (PJS) is caused by mutations in the tumor suppressor gene, STK11, and is characterized by gastrointestinal hamartomas, melanin spots on the lips and the extremities, and an increased risk of developing cancer.
CASE PRESENTATION: We reported an isolated PJS patient who died of colon cancer, whose blood sample was collected together with all the available family members'. The entire coding region of the STK11 gene was amplified by PCR and analyzed by Sanger sequencing, through which, a novel mutation, c.962_963delCC in exon 8 was identified in this patient. This mutation causes a frameshift mutation and a premature termination at codon 358. Protein structure prediction by Swiss-Model indicated a dramatic change and partial loss of the C-terminal domain. We did not observe this mutation in both parents of the proband. Therefore, it is considered a novel de-novo mutation. Furthermore, the mutation was not found in 50 unrelated healthy people.
CONCLUSIONS: The novel mutation we reported here had not been recorded in databases or literature, and the patient who possessed it suffered from PJS and colon cancer. So our results enlarge the spectrum of STK11 variants in PJS patients. This mutation is most likely responsible for development of the PJS phenotype, especially the cancer occurrence.
Zhao ZY, Jiang YL, Li BR, et al.A 23-Nucleotide Deletion in STK11 Gene Causes Peutz-Jeghers Syndrome and Malignancy in a Chinese Patient Without a Positive Family History.
Dig Dis Sci. 2017; 62(11):3014-3020 [PubMed
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BACKGROUND AND AIMS: Peutz-Jeghers syndrome (PJS) is an autosomal-dominant genetic disease caused by mutations in the tumor suppressor gene, STK11, which is characterized by gastrointestinal hamartomas, melanin spots on the lips and the extremities, and an increased risk of developing both gastrointestinal and extraintestinal malignancies.
METHODS AND RESULTS: We treated a PJS patient without a positive family history, who possessed typical clinical manifestations including polyp canceration. In order to explore the genotype of this patient, blood samples were collected from all the available family members. The whole coding region and the flanking regions of the STK11 gene were amplified by polymerase chain reaction and analyzed by Sanger sequencing. Molecular analysis of the STK11 gene here revealed a 23-nucleotide deletion (c.426-448delCGTGCCGGAGAAGCGTTTCCCAG) in exon 3, resulting in a change of 13 codons and a truncating protein (p.S142SfsX13). This mutation was not found in normal individuals in this family including her parents or in 100 control individuals. Protein structure prediction indicated a dramatic loss of the kinase domain and complete loss of the C-terminal regulatory domain.
CONCLUSIONS: The results presented here enlarge the spectrum of STK11 mutation both disease-causing and malignancy-causing.
Daniell J, Plazzer JP, Perera A, Macrae FAn exploration of genotype-phenotype link between Peutz-Jeghers syndrome and STK11: a review.
Fam Cancer. 2018; 17(3):421-427 [PubMed
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Peutz-Jeghers Syndrome (PJS) is an autosomal dominant hereditary polyposis syndrome. Clinical features include hamartomatous polyps, mucocutaneous pigmentation and an increased predisposition towards developing malignancy. Variants in STK11, a tumour suppressor gene, located on Chromosome 19, predispose to PJS. Peutz-Jeghers Syndrome is associated with increased rates of malignancy, particularly gastrointestinal. However, PJS is also associated with increased gynaecological, testicular and thyroid papillary malignancy. Truncating variants in STK11 are thought to predispose to a more severe phenotype. Phenotype severity is based on earlier onset of gastrointestinal pathology arising from the polyps, such as intussusception or earlier onset malignancy. Missense variants are generally considered less severe than truncating variants. There remain a large number of variants of undetermined significance. Studies have attempted to correlate the location of variants with impact on protein structure and overall severity of the PJS phenotype. The results from these cohort studies have consistently found a non-random distribution of variants. Nevertheless, a consensus on phenotype severity based on variant location is yet to be established. A centralised database that collates all known variants would facilitate the interpretation of these variants, best under the governance of an international disease-specific organisation (InSiGHT). In particular, it could help explore the significance of variants based on their type or location. Understanding the genotype-phenotype link between STK11 variants and PJS could allow more personalised care for PJS patients and their families via appropriate risk stratification and personalised and targeted cancer screening.
Chiang JM, Chen TCClinical manifestations and STK11 germline mutations in Taiwanese patients with Peutz-Jeghers syndrome.
Asian J Surg. 2018; 41(5):480-485 [PubMed
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BACKGROUNDS: Clinical manifestations and molecular basis of Taiwanese patients with Peutz-Jeghers syndrome (PJS) were investigated to add the knowledge of phenotype and genotype of the disease.
METHODS: Based on the Pathology Data Bank and the Colorectal Cancer Register, we collected their clinical data. The entire coding sequence of the STK11 gene was amplified and analyzed by sequencing using the genomic DNA.
RESULTS: Fifteen patients diagnosed with PJS from 11 unrelated families were collected until 2015. The median age at the onset of symptoms was 19 years with intussusception as the most frequent presenting symptom. Ten patients developing 11 cancers at various anatomical sites, including two cases of sinonasal cancer, two lung cancers, two breast cancers, two rectal cancers, two gynecological cancers and one small bowel cancer. Five of the deceased patients had died of cancers. The median age of diagnosis of first cancer in the probands was 32 years. Seventy patients (7 of 10) diagnosed before age of 40. Mutations found in eight families included five novel mutations (exon 6, c.843 ins G; exon 8, c.2065 delete A; exon 8, c.G923A, nonsense; exon 6, c.748dupA; and mTOR c.5107dupA) and three previously reported mutations. The other three PJS families without detectable STK11 mutations did not develop malignancies so far.
CONCLUSION: This is the first comprehensive study of patients with Peutz-Jeghers syndrome in the Taiwanese. We have demonstrated that the phenotype of Peutz-Jeghers syndrome varies greatly among the patients. Patients with detectable STK11 mutations have very high risk of developing cancers.
Achatz MI, Porter CC, Brugières L, et al.Cancer Screening Recommendations and Clinical Management of Inherited Gastrointestinal Cancer Syndromes in Childhood.
Clin Cancer Res. 2017; 23(13):e107-e114 [PubMed
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Hereditary gastrointestinal cancer predisposition syndromes have been well characterized, but management strategies and surveillance remain a major challenge, especially in childhood. In October 2016, the American Association for Cancer Research organized the AACR Childhood Cancer Predisposition Workshop in which international experts in care of children with a hereditary risk of cancer met to define surveillance strategies and management of children with cancer predisposition syndromes. In this article, we review the current literature in polyposis syndromes that can be diagnosed in childhood and may be associated with an increased incidence of gastrointestinal neoplasms and other cancer types. These disorders include adenomatous polyposis syndromes (
Colon polyps represent precursor lesions of colon cancers and their malignant potential varies according to histological subtype. A rare subtype of colon polyps is the Peutz-Jeghers (PJ) polyp. PJ polyps mostly occur in the context of Peutz-Jeghers syndrome, which is characterized by the development of multiple polyps in the intestinal tract and hyperpigmentation of oral mucosa and lips. Peutz-Jeghers is an autosomal dominant disorder caused by pathogenic variants of the serine threonine kinase STK11. PJ polyps very rarely occur outside of the syndrome and are then referred to as solitary PJ polyps. Contrary to the situation in Peutz-Jeghers, the genetic basis and the malignant potential of solitary PJ polyps are currently unknown. Here we describe a detailed and comprehensive genetic profile of a solitary PJ polyp. Pathological examination revealed a high tissue homogeneity with >80% epithelial cells. Whole-genome sequencing failed to identify any clonal mutations but demonstrated a significant number of subclonal mutations. No somatic or germline mutations were found at the
Chiang JM, Chen TCA Peutz-Jeghers syndrome family associated with sinonasal adenocarcinoma: 28 years follow up report.
Fam Cancer. 2017; 16(4):555-560 [PubMed
] Related Publications
Peutz-Jeghers syndrome (PJS) is a rare hereditary disorder characterized by hamartomatous polyps in both of the gastrointestinal tract and mucosal pigmentation. It could increase in risk of intestinal and extra-intestinal neoplasms. We here described three cases of sinonasal polyposis in a PJS family and two developed sinonasal type adenocarcinoma. Genetic study revealed a germline STK11/LKB1 mutation on codon 179 (c.C536G, p.P179R) of exon 4. LOH analysis of the LKB1 locus confirms this to be a deleterious mutation. Sinonasal polyposis with malignant transformation could be encountered in PJS patients. Regular follow-up was recommended for the risk of malignant changes in nasal polyps.
BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare disorder characterized by multiple gastrointestinal hamartomatous polyps and mucocutaneous pigmentation. STK11 has been identified as a causative gene for this disease.
CASE PRESENTATION: Herein we report a Chinese Han kindred with PJS. Onset for the PJS signs in three of the patients was rarely as early as at birth. We identified a novel heterozygous mutation (c.440_441delGT, p.Arg147Leufs*15) in the gene STK11, causing a short frameshift followed by a deletion of 63% of the amino acids in the STK protein. This mutation co-segregated with the PJS phenotype, and was absent in two hundred of unrelated ethnicity-matched controls. The mutation led to expression decrease of unaffected STK11 protein in patients than in controls, as well in PJ polyps than in circulating leucocytes from the patients. Phosphorylation levels of the downstream kinase AMPKα altered according with the expression of STK11. These results indicated the possibility that haploinsufficiency and epigenetic reduction of STK11 contributed to the pathogenesis of the disease.
CONCLUSION: This study identifies a novel mutation in the pathogenic gene STK11 leading to PJS.
Tan H, Wei X, Yang P, et al.A lesson from a reported pathogenic variant in Peutz-Jeghers syndrome: a case report.
Fam Cancer. 2017; 16(3):417-422 [PubMed
] Related Publications
Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by mucocutaneous hyperpigmentation, gastrointestinal (GI) hamartmatous polyps, and an increased risk of various malignancies. Pathogenic variants in the LKB1 tumor suppressor gene (also known as STK11) are the major cause of PJS. In this study, compound heterozygous variants of LKB1, c.890G > A/ c.1062C > G and del(exon1)/ c.1062C > G, were identified in two sporadic Chinese PJS cases respectively. Although all these three variants had been related to the autosomal dominant PJS in previous studies, all evidences collected in this study including de novo data, segregation data, population data, in-silico data, and functional data indicated that del(exon1) and c.890G > A are pathogenic in these two PJS families rather than c.1062C > G. This finding would contribute to genetic counseling for individuals carrying the variant c.1062C > G with or without PJS phenotypes. Moreover, this finding reminds genetic counselors that it is necessary to reevaluate the pathogenicity of reported variants in a known Mendelian disorder in order to avoid a misleading decision.
BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder characterized by gastrointestinal (GI) hamartomatous polyps, mucocutaneous hyperpigmentation, and an increased risk of cancer. Mutations in the serine-threonine kinase 11 gene (SKT11) are the major cause of PJS.
CASE PRESENTATION: Blood samples were collected from six PJS families including eight patients. Mutation screening of STK11 gene was performed in these six families by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) assay. Three novel mutations (c.721G > C, c.645_726del82, and del(exon2-5)) and three recurrent mutations (c.752G > A, c.545 T > C and del(exon1)) in STK11 were detected in six Chinese PJS families. Genotype-phenotype correlations suggested that truncating mutations trend to result in severe complications.
CONCLUSION: These findings broaden the mutation spectrum of the STK11 gene and would help clinicians and genetic counselors provide better clinical surveillance for PJS patients, especially for ones carrying truncating mutation.
BACKGROUND Peutz-Jeghers syndrome (PJS) is an autosomal dominant genetic disease. It severely decreases patient quality of life and leads elevated cancer risk. Germline mutation of LKB1 is the leading cause of familial PJS. MATERIAL AND METHODS To characterize the germline mutation of LKB1 gene in Chinese familial and sporadic PJS patients, 14 PJS families, 5 sporadic PJS patients, and 250 healthy adults were collected and genomic DNAs of peripheral blood were extracted. Mutation screenings of LKB1 were performed using MLPA (multiplex ligation-dependent probe amplification), PCR, direct sequencing, and PCR-DHPLC (denaturing high-performance liquid chromatography). RESULTS A total of 12 kinds of germline mutations were found in 9 familial PJS patients, most of which were point mutations (7/12); 4 large deletions of LKB1 were also observed. Of the 12 mutations, 7 were pathogenic (2 were de novo), 4 were just polymorphisms, and 1 was indefinitely pathogenic. No pathogenic mutation in exons of the LKB1 gene was detected in the 5 sporadic PJS patients. The mutation detection rate for the LKB1 gene was 85.7% in our Chinese familial PJS and 63.2% in all Chinese PJS patients. Eight familial PJS patients were identified with pathogenic germline mutations in 14 unrelated families (57.1%). Further methylation detection and analysis showed promoter methylation in carcinomatous polyps. CONCLUSIONS LKB1 gene germline mutation with pathogenic effect is a common cause of familial PJS in Chinese patients; however, it is not the only molecular pathogen of PJS. Methylation in the LKB1 gene promoter region may cause carcinomatous change in intestinal polyps.
Hamartomatous polyps (HPs) in the gastrointestinal (GI) tract are rare compared to other types of GI polyps, yet they are the most common type of polyp in children. The symptoms are usually rectal bleeding, abdominal pain, obstipation, anaemia, and/or small bowel obstruction. The polyps are typically removed concurrently with endoscopy when located in the colon, rectum, or stomach, whereas polyps in the small bowel are removed during push-enteroscopy, device-assisted enteroscopy, or by surgery. HPs can be classified as juvenile polyps or Peutz-Jeghers polyps based on their histopathological appearance. Patients with one or a few juvenile polyps are usually not offered clinical follow-up as the polyp(s) are considered not to harbour any malignant potential. Nevertheless, it is important to note that juvenile polyps and HPs are also found in patients with hereditary hamartomatous polyposis syndromes (HPS). Patients with HPS have an increased risk of cancer, recurrences of polyps, and extraintestinal complications. The syndromes are important to diagnose, as patients should be offered surveillance from childhood or early adolescence. The syndromes include juvenile polyposis syndrome, Peutz-Jeghers syndrome, and the PTEN hamartoma tumour syndrome. Currently, the HPS diagnoses are based on clinical criteria and are often assisted with genetic testing as candidate genes have been described for each syndrome. This thesis is based on six scientific papers. The overall aim of the studies was to expand the knowledge on clinical course and molecular genetics in patients with HPs and HPS, and to investigate research participants' attitude towards the results of extensive genetic testing. Paper I: In the first paper we investigated the occurrence, anatomic distribution, and other demographics of juvenile polyps in the colon and rectum in Denmark in 1995-2014. Based on the Danish Pathology Data Bank we found that 1772 patients had 2108 JPs examined in the period, and we calculated the incidence of juvenile polyps to be between 1:45,000 and 1:65,000. The majority of patients with juvenile polyps were adults and 1% fulfilled to diagnostic criteria of JPS. The majority of patients had a single juvenile polyp. Paper II: In this paper we conducted a review of the HPS based on the current literature. Paper III: We investigated the hypothesis that patients with one or few HPs may have a HPS based on genetic screening. We de-signed a panel of 26 genes associated with HPS and used targeted next generation sequencing in 77 patients with mainly one juvenile polyp. We detected several germ line variants, among them three in ENG, two in BMPR1A, one in PTEN, and one in SMAD4. Although some of the detected variants have been reported previously none could be classified as definitely pathogenic or likely pathogenic according to our variant classification scheme and thus we concluded that genetic screening of patients with one or few JPs are not indicated. Paper IV: In Paper IV we investigated one of the ethical aspects of next generation sequencing: the issue whether research participants in NGS studies should be offered the possibility of not re-ceiving information on incidental genetic findings (the "opting out possibility"). We conducted semi-structures interviews in 127 research participants, and found that the majority (61%) wanted information on all incidentals findings, while 36% wanted information on actionable incidental findings. Only 3% did not want information on incidental findings at all. Paper V: In this paper we wanted to gather information on all Danish patients with Peutz-Jeghers syndrome in order to investigate the phenotype and genotype. Through Danish registers we detected 43 patients of which 14 had deceased. We calculated the prevalence of Peutz-Jeghers syndrome to be approximately one in 195,000 individuals. The median age at diagnosis was 29 years with obstruction of the small bowel as the most frequent presenting symptom. We noted 18 cancer occurrences in the population in both the GI tract and at extraintestinal sites, demonstrating that these patients are predisposed to cancer at various anatomical sites. The study also underlined the wide phenotypic expression of the syndrome. Paper VI: In the last paper we identified patients with juvenile polyposis syndrome, who carry a SMAD4 mutation, and described their genotype and phenotype. We especially investigated whether these patients have symptoms of both juvenile polyposis syndrome and hereditary hemorrhagic telangiectasia. We identified 14 Danish patients. Most of these had symptoms of both conditions and one had aortic root dilatation. Thus, this group of patients requires a multidisciplinary follow-up program.
Zheng B, Wang C, Jia Z, et al.A Clinical and Molecular Genetic Study in 11 Chinese Children With Peutz-Jeghers Syndrome.
J Pediatr Gastroenterol Nutr. 2017; 64(4):559-564 [PubMed
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OBJECTIVES: Peutz-Jeghers syndrome (PJS) is caused by the germline mutations in serine/threonine kinase 11 (STK11) gene. The aim of the present study was to investigate the spectrum of STK11 gene mutations using multiplex ligation-dependent probe amplification (MLPA) assay in combination with direct sequencing in Chinese children with PJS.
METHODS: Nine children who met the clinical criteria for PJS and 2 presumed patients with PJS were enrolled in the present study. Patients' clinical information on polyp characteristics, polyp-related complications, family histories, and so on were reviewed and analyzed. After obtaining informed consent, we performed a mutation analysis of STK11 gene in 11 Chinese patients using MLPA assay and direct sequencing.
RESULTS: By means of MLPA method, we detected exonic deletions in 5 patients. In details, 1 patient had the complete deletion of all 10 exons, 3 patients showed deletions of promoter region and exon 1, and 1 patient had exon deletions from 1 to 9. By direct sequencing of the coding region of STK11 gene, we identified point mutations in 4 patients at c.548T>G/p.Leu183Arg, c.580G>T/p.Asp194Tyr, c.152_153insGG/Asp53GlyfsX12, and c.631delC/Arg211GlyfsX76, respectively, and 3 of them are novel mutations. We failed to find any mutation in left 2 patients who met the clinical criteria of PJS.
CONCLUSIONS: MLPA plus direct sequencing revealed large genomic deletions of STK11 gene in Chinese children with PJS and increased the detecting rate of STK11 gene mutations in Chinese patients with PJS. MLPA combined with direct sequencing could serve as a better strategy for the genetic diagnosis of PJS in Chinese population.
Jelsig AM, Brusgaard K, Hansen TP, et al.Germline variants in Hamartomatous Polyposis Syndrome-associated genes from patients with one or few hamartomatous polyps.
Scand J Gastroenterol. 2016; 51(9):1118-25 [PubMed
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OBJECTIVE: A subgroup of patients with hamartomatous polyps in the GI tract has a hereditary Hamartomatous Polyposis Syndrome with an increased risk of cancer. The distinction between patients with one or few polyps and patients with a syndrome can be difficult. A pathogenic germline mutation can be detected in a majority of HPS patients. This study investigates whether patients with one or few hamartomatous polyps could have a syndrome based on genetic screening of relevant genes.
METHODS: We designed a gene panel including 26 hamartomatous polyposis-associated genes. Using targeted Next Generation Sequencing, DNA samples from 77 patients with 84 hamartomatous polyps were sequenced. The detected germline variants were classified into pathogenicity classes.
RESULTS: We detected several germline variants, among them three in ENG, two in BMPR1A, one in PTEN, and one in SMAD4. Although some of the detected variants have been reported previously none could be definitely pathogenic or likely pathogenic.
CONCLUSIONS: Our study points towards that genetic testing for the Hamartomatous Polyposis Syndromes in patients with one or few polyps does not improve diagnostics, however we illustrate that the clinical significance of genetic variants can be difficult to interpret. A family history of polyps, cancer, or extraintestinal findings or a minimum of 3-5 polyps seems to be relevant information to include before genetic testing.
Kazubskaya TP, Kozlova VM, Filippova MG, et al.[Rare hereditary syndromes associated with polyposis and the development of malignant tumors].
Arkh Patol. 2016 Mar-Apr; 78(2):10-18 [PubMed
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UNLABELLED: Familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome are genetic diseases characterized by gastrointestinal polyps, extraintestinal manifestations, and autosomal dominant inheritance. The carriers of these diseases from early childhood are at risk for neoplasias at different sites, which are symptomatic at various ages.
AIM: to study the clinical organ-specific manifestations in patients with FAP and Peutz-Jeghers, genetics update and possibilities of diagnosis, monitoring, and treatment of these diseases.
MATERIAL AND METHODS: The authors give the results of their examination and follow-up of children with FAP and Peutz-Jeghers hamartoma-polypous syndrome. In addition, current data from PubMed, Medline (including reviews, original articles and case reports) were used.
RESULTS: The main clinical organ-specific signs of multiple tumors in FAP and Peutz-Jeghers syndrome are shown. Data on the assessment of a risk for malignant tumors at various sites in the affected patients and their family members at different ages are provided. Each of these syndromes has a dissimilar genetic foundation. FAP is caused by the germline mutations in the APC gene, Peutz-Jeghers syndrome is by the STK11 gene, which predispose individuals to specifically associated neoplasias and require different follow-up strategies. Information on a phenotype-genotype correlation may serve as a reference point for the possible severity and various manifestations of a disease. An update on the molecular pathogenesis of these diseases is considered.
CONCLUSION: Molecular genetic testing of the genes associated with FAP and Peutz-Jeghers syndromes makes it possible to timely recognize family members at high risk, to plan therapeutic strategy and to affect the course of a disease. The joint participation of pediatricians, proctologists, oncologists, morphologists, geneticists, and molecular biologists is essential to timely recognize the carriers of the syndromes and a better prognosis in these patients.
Mao X, Zhang Y, Wang H, et al.[Mutations of the STK11 and FHIT genes among patients with Peutz-Jeghers syndrome].
Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2016; 33(2):186-90 [PubMed
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OBJECTIVE: To correlate the clinical characteristics with mutations of the STK11 and FHIT genes in 16 patients with Peutz-Jeghers syndrome (PJS).
METHODS: Potential mutations in the coding regions and flanking sequences of the STK11 and FHIT genes were detected with PCR and Sanger sequencing.
RESULTS: Of the 16 patients with PJS, 8 had novel mutations in the coding region of the STK11 gene, 1 had a previously reported mutation. 1 carried a mutation in the exon 10 of the FHIT gene, which is a non-coding region. None of the mutations was detected in the immediate family members. None of the patients with STK11 gene mutations had mutation in the FHIT gene. The mutation rate of the STK11 gene among patients with PJS was 56.25%.
CONCLUSION: Mutations of the STK11 gene are the major cause of PJS. Few such patients had mutations of the FHIT gene. Mutations of the FHIT gene may play a part in the pathogenesis of PJS.
AIM: To investigate multiple polyps in a Chinese Peutz-Jeghers syndrome (PJS) infant.
METHODS: A nine-month-old PJS infant was admitted to our hospital for recurrent prolapsed rectal polyps for one month. The clinical characteristics, a colonoscopic image, the pathological characteristics of the polyps and X-ray images of the intestinal perforation were obtained. Serine threonine-protein kinase 11 (STK11) gene analysis was also performed using a DNA sample from this infant.
RESULTS: Here we describe the youngest known Chinese infant with PJS. Five polyps, including a giant polyp of approximately 4 cm × 2 cm in size, were removed from the infant's intestine. Laparotomy was performed to repair a perforation caused by pneumoperitoneum. The pathological results showed that this child had PJS. Molecular analysis of the STK11 gene further revealed a novel frameshift mutation (c.64_65het_delAT) in exon 1 in this PJS infant.
CONCLUSION: The appropriate treatment method for multiple polyps in an infant must be carefully considered. Our results also show that the STK11 gene mutation is the primary cause of PJS.
Shelygin YA, Pospekhova NI, Shubin VP, et al.[Pilot clinical and genetic study of Russian patients with Peutz-Jeghers syndrome].
Vopr Onkol. 2016; 62(1):112-16 [PubMed
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Peutz-Jeghers syndrome is a rare hereditary syndrome characterized by presence of hamartoma polyps in intestinal tract and usually by mucocutaneous pigmentation. Clinical-genetic characteristics of Russian patients with Peutz-Jeghers syndrome were studied for the first time. Four germline mutations in STK11gene were found in probands from six families and three of them had not been described previously. Clinical pattern of disease in Russian patients included: frequent polyposis of colon and stomach (62,5% and 75%, respectively) along with small bowel; frequent presence of malignant tumors (62,5%). These clinical aspects can help physicians to find out Peutz-Jeghers syndrome. Molecular-genetic testing of individuals should be recommended.
BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disease characterized by gastrointestinal hamartomatous polyps and mucocutaneous melanin spots. Germline mutation of the serine/threonine kinase 11 (STK11) gene are responsible for PJS. In this study, we investigated the clinical characteristics and molecular basis of the disease in Chinese children with PJS.
METHODS: Thirteen children diagnosed with PJS in our hospital were enrolled in this study from 2011 to 2015, and their clinical data on polyp characteristics, intussusceptions events, family histories, etc. were described. Genomic DNA was extracted from whole-blood samples from each subject, and the entire coding sequence of the STK11 gene was amplified by polymerase chain reaction and analyzed by direct sequencing.
RESULTS: The median age at the onset of symptoms was 2 years and 4 months. To date, these children have undergone 40 endoscopy screenings, 17 laparotomies and 9 intussusceptions. Polyps were found in the stomach, duodenum, small bowel, colon and rectum, with large polyps found in 7 children. Mutations were found in eleven children, including seven novel mutations (c.481het_dupA, c.943_944het_delCCinsG, c.397het_delG, c.862 + 1G > G/A, c.348_349het_delGT, and c.803_804het_delGGinsC and c.121_139de l19insTT) and four previously reported mutations (c.658C > C/T, c.890G > G/A, c.1062 C > C/G, and c.290 + 1G > G/A). One PJS patient did not have any STK11 mutations.
CONCLUSIONS: The polyps caused significant clinical consequences in children with PJS, and mutations of the STK11 gene are generally the cause of PJS in Chinese children. This study expands the spectrum of known STK11 gene mutations.
Genetic heterogeneity has been recognised in Peutz-Jeghers syndrome (PJS) (over 230 STK11 gene mutations reported). We report a rare PJS phenotype with early extensive gastrointestinal (GI) presentation and a new genetic variant. The case presented as haematochezia and mucocutaneous pigmentation (the patient was 3 years of age). Endoscopy showed several polyps throughout the stomach/colon (PJ-type hamartomas); the larger polyps were resected. Small bowel imaging detected multiple jejunum/ileum small polyps. During 8 years of follow-up of this asymptomatic patient, an increasing number of diffusely distributed polyps was observed and polypectomies were performed. Subsequently, the patient failed consultations; when the patient was 13 years of age, emergency surgery was required due to small bowel intussusception (ileal polyp). A STK11 gene study identified two missense variants in heterozygous (yet unknown significance but probably pathogenic): c.854T>A (exon 6) and c.446C>T* (exon 2) (*not previously reported). We report two STK11 gene variants (one not previously described) of yet undetermined causality in a paediatric patient presenting with extensive GI involvement at a very early age, with no family medical history. Structural and functional repercussion of the newly described variants should be further investigated.