Wilms Tumor, Aniridia, Genitourinary Anomalies, and Mental Retardation Syndrome (WAGR). WAGR Syndrome is associated with contiguous deletions of the 11p13 area of Chromosome 11, including the PAX6 and WT1 genes. See also: Wilms Tumor.
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Mutated Genes and Abnormal Protein Expression (3)
Clicking on the Gene or Topic will take you to a separate more detailed page. Sort this list by clicking on a column heading e.g. 'Gene' or 'Topic'.
|WT1 ||11p13 ||GUD, AWT1, WAGR, WT33, NPHS4, WIT-2, EWS-WT1 || ||-WT1 deletions in WAGR Syndrome || 30|
|PAX6 ||11p13 ||AN, AN2, FVH1, MGDA, WAGR, ASGD5, D11S812E || ||-PAX6 deletions in WAGR Syndrome || 23|
|BDNF ||11p14.1 ||ANON2, BULN2 || ||-BDNF deletion in WAGR Syndrome || 9|
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
Rare pain-insensitive individuals offer unique insights into how pain circuits function and have led to the development of new strategies for pain control. We investigated pain sensitivity in humans with WAGR (Wilms tumor, aniridia, genitourinary anomaly, and range of intellectual disabilities) syndrome, who have variably sized heterozygous deletion of the 11p13 region. The deletion region can be inclusive or exclusive of the brain-derived neurotrophic factor (BDNF) gene, a crucial trophic factor for nociceptive afferents. Nociceptive responses assessed by quantitative sensory testing demonstrated reduced pain sensitivity only in the WAGR subjects whose deletion boundaries included the BDNF gene. Corresponding behavioral assessments were made in heterozygous Bdnf knockout rats to examine the specific role of Bdnf. These analogous experiments revealed impairment of Aδ- and C-fiber-mediated heat nociception, determined by acute nociceptive thermal stimuli, and in aversive behaviors evoked when the rats were placed on a hot plate. Similar results were obtained for C-fiber-mediated cold responses and cold avoidance on a cold-plate device. Together, these results suggested a blunted responsiveness to aversive stimuli. Our parallel observations in humans and rats show that hemizygous deletion of the BDNF gene reduces pain sensitivity and establishes BDNF as a determinant of nociceptive sensitivity.
BACKGROUND: Wilms tumor, aniridia, genitourinary anomalies and mental retardation (WAGR) syndrome is a rare genetic disorder caused by heterozygous deletions of WT1 and PAX6 at chromosome 11p13. Deletion of BDNF is known eto be associated with hyperphagia and obesity in both humans and animal models; however, neuroendocrine and epigenetic profiles of individuals with WAGR syndrome remain to be determined.
CASE PRESENTATION: We report a 5-year-old girl with the typical phenotype of WAGR syndrome. She showed profound delays in physical growth, motor and cognitive development without signs of obesity. Array comparative genome hybridization (CGH) revealed that she carried a 14.4 Mb deletion at 11p14.3p12, encompassing the WT1, PAX6 and BDNF genes. She experienced recurrent hypoglycemic episodes at 5 years of age. Insulin tolerance and hormonal loading tests showed normal hypothalamic responses to the hypoglycemic condition and other stimulations. Methylation analysis for freshly prepared DNA from peripheral lymphocytes using the pyro-sequencing-based system showed normal patterns of methylation at known imprinting control regions.
CONCLUSIONS: Children with WAGR syndrome may manifest profound delay in postnatal growth through unknown mechanisms. Epigenetic factors and growth-associated genes in WAGR syndrome remain to be characterized.
WAGR syndrome is characterized by Wilm's tumor, aniridia, genitourinary abnormalities and intellectual disabilities. WAGR is caused by a chromosomal deletion that includes the PAX6, WT1 and PRRG4 genes. PRRG4 is proposed to contribute to the autistic symptoms of WAGR syndrome, but the molecular function of PRRG4 genes remains unknown. The Drosophila commissureless (comm) gene encodes a short transmembrane protein characterized by PY motifs, features that are shared by the PRRG4 protein. Comm intercepts the Robo axon guidance receptor in the ER/Golgi and targets Robo for degradation, allowing commissural axons to cross the CNS midline. Expression of human Robo1 in the fly CNS increases midline crossing and this was enhanced by co-expression of PRRG4, but not CYYR, Shisa or the yeast Rcr genes. In cell culture experiments, PRRG4 could re-localize hRobo1 from the cell surface, suggesting that PRRG4 is a functional homologue of Comm. Comm is required for axon guidance and synapse formation in the fly, so PRRG4 could contribute to the autistic symptoms of WAGR by disturbing either of these processes in the developing human brain.
Huynh MT, Boudry-Labis E, Duban B, et al.WAGR syndrome and congenital hypothyroidism in a child with a Mosaic 11p13 deletion.
Am J Med Genet A. 2017; 173(6):1690-1693 [PubMed
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Wilm's tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome, a rare genetic disorder, is caused by the loss of 11p13 region including PAX6 and WT1. We report novel findings in a 28-month-old boy with aniridia, Wilm's tumor, congenital hypothyroidism, and sublingual thyroid ectopia. He was found to have a mosaic 5.28 Mb interstitial deletion of chromosome 11p13 deleting PAX6 and WT1. In order to clarify the mechanism underlying his thyroid dysgenesis, sequence analysis of candidate thyroid developmental genes was performed. We identified a FOXE1: c.532_537delGCCGCC p.(Ala178_Ala179del) variant that predisposes to thyroid ectopia. Taken together, this is the first report of mosaic 11p13 deletion in association with thyroid dysgenesis. We also propose a model of complex interactions of different genetic variants for this particular phenotype in the present patient.
Vasilyeva TA, Voskresenskaya AA, Käsmann-Kellner B, et al.Molecular analysis of patients with aniridia in Russian Federation broadens the spectrum of PAX6 mutations.
Clin Genet. 2017; 92(6):639-644 [PubMed
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Congenital aniridia is a severe autosomal dominant congenital panocular disorder, mainly associated with pathogenic variants in the PAX6 gene. The objective of the study was to investigate the mutational and clinical spectra of congenital aniridia in a cohort of 117 patients from Russia. Each patient underwent detailed ophthalmological examination. From 91 unrelated families, 110 patients were diagnosed with congenital aniridia and 7 with WAGR syndrome (Wilms tumor, Aniridia, Genitourinary anomalies, and mental Retardation syndrome). The clinical presentation in aniridia patients varied from the complete bilateral absence of the iris (75.5%) to partial aniridia or iris hypoplasia (24.5%). Additional ocular abnormalities were consistent with previous reports. In our cohort, we saw a previously not described high percentage of patients (45%) who showed non-ocular phenotypes. Prevalence of deletions coherent with WAGR syndrome appeared to be 19.4% out of sporadic patients. Among the other aniridia cases, PAX6 deletions were identified in 18 probands, and small intragenic changes were detected in 58 probands with 27 of these mutations being novel and 21 previously reported. In 3 families mosaic mutation was transmitted from a subtly affected parent. Therefore, PAX6 mutations explained 96.7% of aniridia phenotypes in this study with only 3 of 91 probands lacking pathogenic variants in the gene.
Chromosomal deletions at 11p13 are a frequent cause of congenital Aniridia, a rare pan-ocular genetic disease, and of WAGR syndrome, accounting up to 30% of cases. First-tier genetic testing for newborn with aniridia, to detect 11p13 rearrangements, includes Multiplex Ligation-dependent Probe Amplification (MLPA) and karyotyping. However, neither of these approaches allow obtaining a complete picture of the high complexity of chromosomal deletions and breakpoints in aniridia. Here, we report the development and validation of a customized targeted array-based comparative genomic hybridization, so called WAGR-array, for comprehensive high-resolution analysis of CNV in the WAGR locus. Our approach increased the detection rate in a Spanish cohort of 38 patients with aniridia, WAGR syndrome and other related ocular malformations, allowing to characterize four undiagnosed aniridia cases, and to confirm MLPA findings in four additional patients. For all patients, breakpoints were accurately established and a contiguous deletion syndrome, involving a large number of genes, was identified in three patients. Moreover, we identified novel microdeletions affecting 3' PAX6 regulatory regions in three families with isolated aniridia. This tool represents a good strategy for the genetic diagnosis of aniridia and associated syndromes, allowing for a more accurate CNVs detection, as well as a better delineation of breakpoints. Our results underline the clinical importance of performing exhaustive and accurate analysis of chromosomal rearrangements for patients with aniridia, especially newborns and those without defects in PAX6 after diagnostic screening.
For more than 30 years, WT1 mutations have been associated with complex developmental syndromes involving the kidney. Acting as a transcription factor, WT1 is expressed throughout the nephron and controls the reciprocal interactions and phenotypic changes required for normal renal development. In the adult, WT1 expression remains extremely high in the renal podocyte, and at a lower level in the parietal epithelial cells. Wt1-null mice are unable to form kidneys . Unsurprisingly, WT1 mutations lead to significant abnormalities of the renal and genitourinary tract, causing a number of human diseases including syndromes such as Denys-Drash syndrome, Frasier syndrome, and WAGR syndrome. Recent methodological advances have improved the identification of WT1 mutations, highlighting its importance even in nonsyndromic renal disease, particularly in steroid-resistant nephrotic syndrome. This vast spectrum of WT1-related disease typifies the varied and complex activity of WT1 in development, disease, and tissue maintenance.
Cytogenetic anomalies should be considered in individuals with multiple congenital anomalies. DNA methylation analysis is the most sensitive initial test in evaluating for Prader-Willi and Angelman syndromes. The timely identification of cytogenetic anomalies allows for prompt initiation of early intervention services to maximize the potential of every individual as they grow older. Although many of these conditions are rare, keeping them in mind can have a profound impact on the clinical course of affected individuals. This article reviews some of the more common genetic syndromes.
Hutson JM, Grover SR, O'Connell M, Pennell SDMalformation syndromes associated with disorders of sex development.
Nat Rev Endocrinol. 2014; 10(8):476-87 [PubMed
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When embryological development of the internal and/or external genitalia is disrupted, the patient presents with a disorder of sex development (DSD) in the neonatal period or sometime later in life. Some of these patients have other, nongenital malformations, which makes their overall management more complex than if they just had a DSD. This Review summarises these malformation syndromes and discusses the recent research into their aetiology. The genetic causes of these malformation syndromes, when they are known, will also be described. Many specific genetic mutations are now known in malformation syndromes with a defect in hormonal function. By contrast, the genetic causes remain unknown in many nonhormonal morphological anomalies that affect the genitalia.
AGR syndrome (the clinical triad of aniridia, genitourinary anomalies, and mental retardation, a subgroup of WAGR syndrome for Wilm's tumor, aniridia, genitourinary anomalies, and mental retardation) is a rare syndrome caused by a contiguous gene deletion in the 11p13-14 region. However, the mechanisms of WAGR syndrome pathogenesis are elusive. In this study we provide evidence that LGR4 (also named GPR48), the only G-protein-coupled receptor gene in the human chromosome 11p12-11p14.4 fragment, is the key gene responsible for the diseases of AGR syndrome. Deletion of Lgr4 in mouse led to aniridia, polycystic kidney disease, genitourinary anomalies, and mental retardation, similar to the pathological defects of AGR syndrome. Furthermore, Lgr4 inactivation significantly increased cell apoptosis and decreased the expression of multiple important genes involved in the development of WAGR syndrome related organs. Specifically, deletion of Lgr4 down-regulated the expression of histone demethylases Jmjd2a and Fbxl10 through cAMP-CREB signaling pathways both in mouse embryonic fibroblast cells and in urinary and reproductive system mouse tissues. Our data suggest that Lgr4, which regulates eye, kidney, testis, ovary, and uterine organ development as well as mental development through genetic and epigenetic surveillance, is a novel candidate gene for the pathogenesis of AGR syndrome.
Yamamoto T, Togawa M, Shimada S, et al.Narrowing of the responsible region for severe developmental delay and autistic behaviors in WAGR syndrome down to 1.6 Mb including PAX6, WT1, and PRRG4.
Am J Med Genet A. 2014; 164A(3):634-8 [PubMed
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Interstitial deletions of the 11p13 region are known to cause WAGR (Wilms tumor, aniridia, genitourinary malformation, and "mental retardation") syndrome, a contiguous gene deletion syndrome due to haploinsufficiencies of the genes in this region, including WT1 and PAX6. Developmental delay and autistic features are major complications of this syndrome. Previously, some genes located in this region have been suggested as responsible for autistic features. In this study, we identified two patients who showed the chromosomal deletions involving 11p13. Patient 1, having an 8.6 Mb deletion of chr11p14.1p12:29,676,434-38,237,948, exhibited a phenotype typical of WAGR syndrome and had severe developmental delay and autistic behaviors. On the other hand, Patient 2 had a larger aberration region in 11p14.1-p12 which was split into two regions, that is, a 2.2-Mb region of chr11p14.1: 29,195,161-31,349,732 and a 10.5-Mb region of chr11p13p12: 32,990,627-43,492,580. As a consequence, 1.6 Mb region of the WAGR syndrome critical region was intact between the two deletions. This patient showed no symptom of WAGR syndrome and no autistic behaviors. Therefore, the region responsible for severe developmental delay and autistic features on WAGR syndrome can be narrowed down to the region remaining intact in Patient 2. Thus, the unique genotype identified in this study suggested that haploinsufficiencies of PAX6 or PRRG4 included in this region are candidate genes for severe developmental delay and autistic features characteristic of WAGR syndrome.
Approximately 1% of all live births exhibit a minor or major congenital anomaly. Of these approximately one-third display craniofacial abnormalities which are a significant cause of infant mortality and dramatically affect national health care budgets. To date, more than 700 distinct craniofacial syndromes have been described and in this review, we discuss the etiology, pathogenesis and management of facial dysostoses with a particular emphasis on Treacher Collins, Nager and Miller syndromes. As we continue to develop and improve medical and surgical care for the management of individual conditions, it is essential at the same time to better characterize their etiology and pathogenesis. Here we describe recent advances in our understanding of the development of facial dysostosis with a view towards early in utero identification and intervention which could minimize the manifestation of anomalies prior to birth. The ultimate management for any craniofacial anomaly however, would be prevention and we discuss this possibility in relation to facial dysostosis.
Han JC, Thurm A, Golden Williams C, et al.Association of brain-derived neurotrophic factor (BDNF) haploinsufficiency with lower adaptive behaviour and reduced cognitive functioning in WAGR/11p13 deletion syndrome.
Cortex. 2013 Nov-Dec; 49(10):2700-10 [PubMed
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In animal studies, brain-derived neurotrophic factor (BDNF) is an important regulator of central nervous system development and synaptic plasticity. WAGR (Wilms tumour, Aniridia, Genitourinary anomalies, and mental Retardation) syndrome is caused by 11p13 deletions of variable size near the BDNF locus and can serve as a model for studying human BDNF haploinsufficiency (+/-). We hypothesized that BDNF+/- would be associated with more severe cognitive impairment in subjects with WAGR syndrome. Twenty-eight subjects with WAGR syndrome (6-28 years), 12 subjects with isolated aniridia due to PAX6 mutations/microdeletions (7-54 years), and 20 healthy controls (4-32 years) received neurocognitive assessments. Deletion boundaries for the subjects in the WAGR group were determined by high-resolution oligonucleotide array comparative genomic hybridization. Within the WAGR group, BDNF+/- subjects (n = 15), compared with BDNF intact (+/+) subjects (n = 13), had lower adaptive behaviour (p = .02), reduced cognitive functioning (p = .04), higher levels of reported historical (p = .02) and current (p = .02) social impairment, and higher percentage meeting cut-off score for autism (p = .047) on Autism Diagnostic Interview-Revised. These differences remained nominally significant after adjusting for visual acuity. Using diagnostic measures and clinical judgement, 3 subjects (2 BDNF+/- and 1 BDNF+/+) in the WAGR group (10.7%) were classified with autism spectrum disorder. A comparison group of visually impaired subjects with isolated aniridia had cognitive functioning comparable to that of healthy controls. In summary, among subjects with WAGR syndrome, BDNF+/- subjects had a mean Vineland Adaptive Behaviour Compose score that was 14-points lower and a mean intelligence quotient (IQ) that was 20-points lower than BDNF+/+ subjects. Our findings support the hypothesis that BDNF plays an important role in human neurocognitive development.
Rodríguez-López R, Pérez JM, Balsera AM, et al.The modifier effect of the BDNF gene in the phenotype of the WAGRO syndrome.
Gene. 2013; 516(2):285-90 [PubMed
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Individuals who are carriers of deletions of various sizes that cause haploinsufficiency in the contiguous WT1 and PAX6 genes, located on chromosome 11p13 approximately 4 Mb centromeric to the BDNF gene, are susceptible to Wilms tumor, aniridia, mental retardation, genitourinary anomalies and obesity (WAGRO syndrome). The molecular characterization of the wide deletion 11p15.1p12 arr (18676926-36576388) x1 dn in a child with 3 years and 4 months of age only affected by aniridia, predicts not only other serious associated diseases, but also allows us to hypothesize a specific phenotype of mental impairment, conduct alterations and childhood obesity, possibly added to the onset of metabolic alterations. The variable appearance and/or description of haploinsufficiency for obesity susceptibility in the WAGR syndrome mainly depends on the critical region located within 80 kb of exon 1 of BDNF. The relationship between genetic variation based on the genotype combinations of the 4 gene SNPs tagging the BDNF gene and the body mass index (BMI) was studied. The polymorphic variability was similarly distributed in 218 children suffering a severe and non-syndromic obesity from families at high risk for obesity, as compared with 198 controls. The corroborated role of the BDNF gene as highly susceptible to severe syndromic obesity has not already been evidenced in the molecular basis of overweight attributed to the common polygenic principles. Its potential role as risk modifier variant to provoke more severe phenotype has not yet been demonstrated. Some genetic variants of brain-derived neurotrophic factor (BDNF) have resulted in important disorders of energy balance, but it is essential to know exactly their deleterious human capacity because they play a fundamental role in the development and plasticity of the central nervous system in regulating food intake. The existence of polymorphic amino acid changes of unknown functional significance in patients carrying the haploinsufficiency of the BDNF gene could constitute an adequate model to study in depth their effects.
Terminal or interstitial deletions of Xp (Xp22.2→Xpter) in males have been recognized as a cause of contiguous gene syndromes showing variable association of apparently unrelated clinical manifestations such as Leri-Weill dyschondrosteosis (SHOX), chondrodysplasia punctata (CDPX1), mental retardation (NLGN4), ichthyosis (STS), Kallmann syndrome (KAL1), and ocular albinism (GPR143). Here we present a case of a 13.5 yr old boy and sister with a same terminal deletion of Xp22.2 resulting in the absence of genes from the telomere of Xp to GPR143 of Xp22. The boy manifested the findings of all of the disorders mentioned above. We began a testosterone enanthate monthly replacement therapy. His sister, 11 yr old, manifested only Leri-Weill dyschondrosteosis, and had engaged in growth hormone therapy for 3 yr. To the best of our knowledge, this is the first report of a male with a 9.7 Mb terminal Xp deletion including the OA1 locus in Korea.
Gucev Z, Muratovska O, Laban N, et al.Billateral polycystic kidneys in a girl with WAGR syndrome.
Indian J Pediatr. 2011; 78(10):1290-2 [PubMed
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The WAGR contiguous gene deletion syndrome is a combination of Wilms tumor, aniridia, genito-urinary abnormalities, and mental retardation. An 8.5-year-old girl was initially investigated at the age of 18 months for congenital bilateral aniridia, cataracts, glaucoma and epicantus. The ultrasound (US) scan showed polycystic kidney disease. FISH study revealed deletion of the WT1 and PAX6 gene in the 11p13 WAGR region. Forty days after the first kidney US, the second US revealed a 3 cm tumor in the right kidney: a Wilms tumour, treated successfully with the Wilm's tumor protocol. The authors conclude that the identification of the deletions in the WAGR region in patients with aniridia should definitely be done. In addition, Wilms tumor can have a very rapid growth, which, per se requires frequent and careful ultrasound kidney controls. Polycystic kidneys can be part of the WAGR presentation.
Demir HA, Varan A, Utine EG, et al.WAGR syndrome with tetralogy of Fallot and hydrocephalus.
J Pediatr Hematol Oncol. 2011; 33(4):e174-5 [PubMed
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Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation (WAGR) syndrome occurs sporadically due to deletion of chromosome 11p13. A variety of other abnormalities involving different systems have been reported in patients with WAGR syndrome. We report on a patient with WAGR syndrome with accompanying tetralogy of Fallot and hydrocephalus.
Li PC, Yao Q, Ren X, et al.[Analysis of PAX6 gene in a Chinese family with congenital aniridia].
Zhonghua Yan Ke Za Zhi. 2009; 45(10):931-4 [PubMed
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OBJECTIVE: To explore the pathogenic mutation in a Chinese family with congenital aniridia.
METHODS: It is a case-control study. All 21 members of the family underwent a comprehensive ophthalmic examination and family line investigation. Mononuclear cell was isolated from peripheral blood and genomic DNA was prepared by genomic DNA purification kit. All fourteen exons of the PAX6 gene were amplified by polymerase chain reaction (PCR) from proband's genomic DNA. PCR products of each exon were analyzed by direct sequencing.
RESULTS: A nonsense mutation (Q310X) in exon 11 of PAX6 gene was detected by sequencing analysis in the proband III2. This mutation cause the 301st amino acids codon switch from CAA to TAA and the codogenic amino acids altered from glutamine glutaminic acid to strong terminal codon. This mutation is also detected in all 11 patients of this family, but not present in the unaffected members in this family.
CONCLUSION: The premature translation termination of PAX6 gene caused by a nonsense mutation of Q310X should be responsible for congenital aniridia in this Chinese family.
Xu S, Han JC, Morales A, et al.Characterization of 11p14-p12 deletion in WAGR syndrome by array CGH for identifying genes contributing to mental retardation and autism.
Cytogenet Genome Res. 2008; 122(2):181-7 [PubMed
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WAGR (Wilms tumor, Aniridia, Genitourinary malformations and mental Retardation) syndrome is a rare genomic disorder caused by deletion of the 11p14-p12 chromosome region. The majority of WAGR patients have mental retardation and behavioral problems, and more than 20% of the patients also have features of autism. While the Wilms tumor/genitourinary anomalies and aniridia are caused by deletion of WT1 and PAX6 respectively, the genomic cause of mental retardation and autism in WAGR syndrome remains unknown. Using oligonucleotide arrays, we have characterized the 11p14-p12 deletions in 31 patients and identified all the genes involved in each deletion. The deletions had sizes ranging from 4.9 to 23 Mb that encompass 18-62 genes (40 on average). In addition to WT1 and PAX6, all the patients had deletion of PRRG4 (transmembrane gamma-carboxyglutamic acid protein 4). The majority of them had deletion of BDNF (brain-derived neurotrophic factor) and SLC1A2 [solute carrier family 1 (glial high affinity glutamate transporter) member 2]. Deletion of BDNF and SLC1A2 occurred in patients with autism more frequently than in those without autism. Literature review on the functions of the genes suggests that haploinsufficiency of SLC1A2, PRRG4, and BDNF may contribute to mental retardation and behavioral problems. In particular, BDNF may modulate the risk of autism in WAGR patients as suggested by its link with Rett syndrome as a target of MECP2. We observed that all the de novo deletions occurred in the chromosome 11 inherited from the father in the families genotyped, implying a predisposition for de novo mutations occurring in spermatogenesis and possible involvement of imprinting in cognitive impairment in WAGR patients.
Tyagi R, Shenoy AR, Visweswariah SSCharacterization of an evolutionarily conserved metallophosphoesterase that is expressed in the fetal brain and associated with the WAGR syndrome.
J Biol Chem. 2009; 284(8):5217-28 [PubMed
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Among the human diseases that result from chromosomal aberrations, a de novo deletion in chromosome 11p13 is clinically associated with a syndrome characterized by Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR). Not all genes in the deleted region have been characterized biochemically or functionally. We have recently identified the first Class III cyclic nucleotide phosphodiesterase, Rv0805, from Mycobacterium tuberculosis, which biochemically and structurally belongs to the superfamily of metallophosphoesterases. We performed a large scale bioinformatic analysis to identify orthologs of the Rv0805 protein and identified many eukaryotic genes that included the human 239FB gene present in the region deleted in the WAGR syndrome. We report here the first detailed biochemical characterization of the rat 239FB protein and show that it possesses metallophosphodiesterase activity. Extensive mutational analysis identified residues that are involved in metal interaction at the binuclear metal center. Generation of a rat 239FB protein with a mutation corresponding to a single nucleotide polymorphism seen in human 239FB led to complete inactivation of the protein. A close ortholog of 239FB is found in adult tissues, and biochemical characterization of the 239AB protein demonstrated significant hydrolytic activity against 2',3'-cAMP, thus representing the first evidence for a Class III cyclic nucleotide phosphodiesterase in mammals. Highly conserved orthologs of the 239FB protein are found in Caenorhabditis elegans and Drosophila and, coupled with available evidence suggesting that 239FB is a tumor suppressor, indicate the important role this protein must play in diverse cellular events.
BACKGROUND: Brain-derived neurotrophic factor (BDNF) has been found to be important in energy homeostasis in animal models, but little is known about its role in energy balance in humans. Heterozygous, variably sized, contiguous gene deletions causing haploinsufficiency of the WT1 and PAX6 genes on chromosome 11p13, approximately 4 Mb centromeric to BDNF (11p14.1), result in the Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome. Hyperphagia and obesity were observed in a subgroup of patients with the WAGR syndrome. We hypothesized that the subphenotype of obesity in the WAGR syndrome is attributable to deletions that induce haploinsufficiency of BDNF.
METHODS: We studied the relationship between genotype and body-mass index (BMI) in 33 patients with the WAGR syndrome who were recruited through the International WAGR Syndrome Association. The extent of each deletion was determined with the use of oligonucleotide comparative genomic hybridization.
RESULTS: Deletions of chromosome 11p in the patients studied ranged from 1.0 to 26.5 Mb; 58% of the patients had heterozygous BDNF deletions. These patients had significantly higher BMI z scores throughout childhood than did patients with intact BDNF (mean [+/-SD] z score at 8 to 10 years of age, 2.08+/-0.45 in patients with heterozygous BDNF deletions vs. 0.88+/-1.28 in patients without BDNF deletions; P=0.03). By 10 years of age, 100% of the patients with heterozygous BDNF deletions (95% confidence interval [CI], 77 to 100) were obese (BMI > or = 95th percentile for age and sex) as compared with 20% of persons without BDNF deletions (95% CI, 3 to 56; P<0.001). The critical region for childhood-onset obesity in the WAGR syndrome was located within 80 kb of exon 1 of BDNF. Serum BDNF concentrations were approximately 50% lower among the patients with heterozygous BDNF deletions (P=0.001).
CONCLUSIONS: Among persons with the WAGR syndrome, BDNF haploinsufficiency is associated with lower levels of serum BDNF and with childhood-onset obesity; thus, BDNF may be important for energy homeostasis in humans.
Mutations in the PAX6 gene have been implicated in aniridia, a congenital malformation of the eye with severe hypoplasia of the iris. However, not all aniridia cases can be explained by mutations in the PAX6 gene. The purpose of this study was to enhance the molecular diagnosis of aniridia using multiplex ligation-dependent probe amplification (MLPA). Total genomic DNA was isolated from peripheral blood of 70 unrelated probands affected with aniridia. Polymerase chain reaction (PCR) was performed followed by automated bidirectional sequencing. Additionally, MLPA was performed. We identified 24 different point mutations in the PAX6 gene in 34 patients after sequencing. In eight additional patients, we identified a deletion of one or more exons of the PAX6 gene or in the 3' regulatory region of the PAX6 gene using MLPA. This work demonstrates the necessity to screen for larger deletions in the region of the PAX6 gene in addition to the sequencing of exons in the PAX6 gene. The mutation detection rate will increase from 49% to 60%. This shows that MLPA substantially enhances the molecular diagnosis of aniridia.
Uccini S, Perotti D, Colarossi C, et al.Molecular evidence of the independent origin of multiple Wilms tumors in a case of WAGR syndrome.
Pediatr Blood Cancer. 2008; 51(3):344-8 [PubMed
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BACKGROUND: This study investigated the genetic events leading to tumorigenesis in a patient affected with WAGR syndrome who developed multiple distinct Wilms tumors (WTs).
PROCEDURE AND RESULTS: At 1 year of age, the child developed two synchronous bilateral WTs that were resected by partial nephrectomy. Histologically, these tumors were fetal rhabdomyomatous nephroblastomas. Immunohistochemical study revealed the absence of nuclear expression of WT1 protein, while beta-catenin protein was expressed at nuclear level by the large majority of tumor cells. Molecular investigations of WT1 gene and exon 3 of beta-catenin (CTNNB1) gene detected no mutations. At 4 years of age, 28 months after the chemotherapy completion, a third WT was diagnosed in the left kidney, and surgically removed before any further chemotherapy. Nine months after surgery, a metastasis was detected in the left lung. Both the third renal tumor and the lung metastasis showed a blastema-predominant morphology. Immunohistochemistry confirmed the lack of expression of WT1 protein, while beta-catenin protein was expressed at nuclear level by the large majority of tumor cells. Molecular analysis of the third renal tumor and the lung metastasis revealed a 4 bp deletion in exon 7 of WT1 gene, leading to a frameshift of the reading frame and to a premature stop of the translation (c.925_928delACTC, p.T309LfsX71); no mutations in the exon 3 of the beta-catenin gene were documented.
CONCLUSIONS: These data demonstrate that multiple WTs can arise as a consequence of different genetic events in a patient with genetic predisposition, such as WAGR syndrome.
Dahan K, Kamal M, Noël LH, et al.Small glomeruli in WAGR (Wilms Tumor, Aniridia, Genitourinary Anomalies and Mental Retardation) syndrome.
Am J Kidney Dis. 2007; 49(6):793-800 [PubMed
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BACKGROUND: Wilms tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is a genetic disorder caused by a deletion of band 11p13, which results in the loss of 1 allele of the Wilms tumor suppressor gene (WT1). It is not classically associated with nephropathies, but increased rates of renal failure are reported. Denys-Drash syndrome (DDS), caused by mutations in the WT1 gene affecting the third or second zinc finger, is characterized by a triad of glomerulopathy progressing rapidly to end-stage renal disease, male hermaphroditism, and Wilms tumor. In patients with DDS, small glomeruli were observed.
METHODS: We reviewed histological findings of nontumoral kidney samples of 7 patients with WAGR syndrome at the time of tumor surgery.
RESULTS: Median glomerular diameter was 110 +/- 37 microm in patients with WAGR syndrome versus 125 +/- 18.5 microm in controls (P < 0.0001).
CONCLUSION: The presence of small glomeruli in patients with WAGR syndrome, as in those with DDS, suggests a specific defect of WT1 function in development and a specific role of WT1 allele loss in the development of renal failure in these patients.
Braun KP, May M, Erler T, Hoschke B[Multicystic renal tumor in a patient with WAGR syndrome].
Urologe A. 2007; 46(6):671-4 [PubMed
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The WAGR syndrome is a combination of Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation. We report on a 2-year-old boy, who had a deletion of the aniridia gene PAX6 and the Wilms' tumor gene 1 (WT1 gene). At the age of 23 months, a 1.7 x 1.9 cm-sized intrarenal tumor was detected by ultrasound examination. According to the protocol of the SIOP study, a cycle of neoadjuvant chemotherapy was prescribed followed by a left-sided nephrectomy. However, postsurgical histomorphology failed to confirm the suspected diagnosis of Wilms' tumor and instead revealed dysgenetic cysts of the kidney. Based on the image morphology in connection with the deletion of the WT1 gene, the tentative diagnosis of a nephroblastoma had to be made. The study protocol of the SIOP does not permit another therapy algorithm.
Termine C, Parigi G, Rossi M, et al.WAGR syndrome: is the 'R' always justified?
Clin Dysmorphol. 2007; 16(1):69-70 [PubMed
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Although mild-to-moderate intellectual disability is usually considered part of WAGR syndrome (Wilms' tumour (WT), Aniridia, Genital abnormalities, and metal Retardation, due to 11p13 deletion) the neuropsychological profile of the syndrome is little reported in the literature. We report about a 12-year-old boy presenting with WAGR syndrome (WT, right complete aniridia, bilateral cryptorchidism, interstitial deletion involving band 11p13) but with no mental retardation. An in-depth clinical evaluation revealed no behavioural or social problems and the child's neuropsychological profile was found to be within the normal range for all abilities and functions investigated (with the exception of an impulsive cognitive style and some difficulties in academic skills). This case underlines the importance of in-depth neuropsychological evaluation that includes not only IQ measurement, but also examination of attention and academic skills, in order to establish the complete phenotypical profile of WAGR patients, rather than labelling them as learning disabled (i.e. mental retardation).
Jung R, Rauch A, Salomons GS, et al.Clinical, cytogenetic and molecular characterization of a patient with combined succinic semialdehyde dehydrogenase deficiency and incomplete WAGR syndrome with obesity.
Mol Genet Metab. 2006; 88(3):256-60 [PubMed
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We describe the clinical course, as well as cytogenetic and molecular findings, of a 3-year-old obese boy with psychomotor retardation who exhibited two rare conditions: succinic semialdehyde dehydrogenase deficiency (SSADH deficiency, MIM 271980), a disorder of gamma-aminobutyric acid metabolism with a heterogeneous clinical spectrum, and partial Wilms' tumor, aniridia, genital abnormalities, and mental retardation (WAGR) syndrome, an association between Wilms' tumor, aniridia, genitourinary malformations, and mental retardation due to mutations involving the short arm of chromosome 11, particularly deletions at the chromosomal region 11p13 (MIM 194072). Diagnosis of SSADH deficiency in our patient was established by demonstration of absent enzyme activity in isolated leucocytes, and was associated with a novel missense mutation (c.587G>A; p.Gly196Asp) in the SSADH coding sequence. We further confirmed an incomplete WAGR syndrome in this boy [karyotype 46, XY, del (11) (p13p14.2)] with a normal WT1 (Wilms' tumor) gene and an absence of pathology in the genitourinary tract, but with obesity (WAGR syndrome with obesity, WAGRO syndrome). The patient also exhibited distinctive cerebral anomalies such as increased signals of the globi pallidi, internal hydrocephalus and cerebellar vermian atrophy. However, treatment options for this patient are limited, including supportive treatment, physiotherapy, special educational training, and vigabatrin. In summary, we report the first patient with the exceptional rare findings of both SSADH deficiency and partial WAGR/WAGRO syndrome.
Fischbach BV, Trout KL, Lewis J, et al.WAGR syndrome: a clinical review of 54 cases.
Pediatrics. 2005; 116(4):984-8 [PubMed
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WAGR syndrome is a rare genetic disorder characterized by a de novo deletion of 11p13 and is clinically associated with Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (W-A-G-R). Although the genotypic defects in WAGR syndrome have been well established, the large variety of phenotypic manifestations of the syndrome has never been reported. We report on 54 cases of WAGR syndrome to demonstrate both the classical clinical signs and nonclassical manifestations found in a large population of individuals with this disorder. An understanding of WAGR syndrome and its clinical findings can provide important insight regarding the functions of the involved genetic region. Recommendations for diagnosis, evaluation, and surveillance of patients with WAGR syndrome are also presented.
Farooqi ISGenetic and hereditary aspects of childhood obesity.
Best Pract Res Clin Endocrinol Metab. 2005; 19(3):359-74 [PubMed
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Genetic factors are involved in the regulation of body weight and in determining individual responses to environmental factors such as diet and exercise. The identification and characterization of monogenic obesity syndromes have led to an improved understanding of the precise nature of the inherited component of severe obesity and has had undoubted medical benefits, whilst helping to dispel the notion that obesity represents an individual defect in behaviour with no biological basis. For individuals at highest risk of the complications of severe obesity, such findings provide a starting point for providing more rational mechanism-based therapies, as has successfully been achieved for one disorder, congenital leptin deficiency.
Brémond-Gignac D, Crolla JA, Copin H, et al.Combination of WAGR and Potocki-Shaffer contiguous deletion syndromes in a patient with an 11p11.2-p14 deletion.
Eur J Hum Genet. 2005; 13(4):409-13 [PubMed
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Aniridia, Wilms tumor, genitourinary abnormalities, growth and mental retardation are the cardinal features of the WAGR 11p13 deletion syndrome. The Potocki-Schaffer syndrome or proximal 11p deletion syndrome (previously DEFECT11 syndrome) is a contiguous gene syndrome associated with deletions in 11p11.2, principal features of which are multiple exostoses and enlarged parietal foramina. Mental handicap, facial dysmorphism and craniosynostosis may also be associated. We report a patient with combined WAGR and Potocki-Shaffer syndromes, and obesity. She presented with aniridia, cataract, nystagmus, corneal ulcers and bilateral congenital ptosis. A left nephroblastoma was detected at 15 months. Other features included moderate developmental delay, growth deficiency, facial dysmorphism, multiple exostoses and cranial lacunae. High-resolution and molecular cytogenetics confirmed a del(11)(p11.2p14.1) deletion with a proximal breakpoint between the cosmid DO8153 and the BAC RP11-104M24 to a distal breakpoint between cosmids CO8160 (D11S151) and F1238 (D11S1446). The deletion therefore includes EXT2, ALX4, WT1 and PAX6. This case appears to be the second patient reported with this combined deletion syndrome and confirms the association of obesity in the WAGR spectrum, a feature previously reported in four cases, and for which the acronym WAGRO has been suggested. Molecular and follow-up data on the original WAGRO case are briefly presented.