WAGR(O?) syndrome and congenital ptosis caused by an unbalanced t(11;15)(p13;p11.2)dn demonstrating a 7 megabase deletion by FISH

Aniridia usually occurs in isolation, but may also occur as part of the WAGR contiguous gene deletion syndrome, which includes Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation. The aniridia and predisposition for Wilms tumor seen in WAGR are caused by haploinsufficiency for PAX 6 and WT1, respectively. We present a female infant with aniridia, bilateral ptosis, bilateral posterior capsular cataracts, nystagmus, left-sided glaucoma, microcephaly, mild unilateral hydronephrosis, poor linear growth, and gross motor delay consistent with a clinical diagnosis of WAGR syndrome. In addition, weight-for-height ratio at 12 months is at the 94th centile, raising the possibility of a diagnosis of WAGRO (WAGR + Obesity). Chromosome analysis revealed a translocation (11;15)(p13;p11.2) which has not been previously associated with a diagnosis of WAGR. Subsequent clinical WAGR fluorescent in situ hybridization (FISH) analysis demonstrated a deletion of 11p13 including PAX6 and WT1. A complete FISH-mapping of the breakpoints on chromosome 11 revealed a 7 Mb deletion within 11p13-11p14. The patient is examined in light of other reported patients with deletions and/or translocations involving the regions between 11p12 --> 11p14 including patients with WAGR + obesity (WAGRO) as well as with other reported patients with aniridia and congenital ptosis.     

Combination of WAGR and Potocki-Shaffer contiguous deletion syndromes in a patient with an 11p11.2-p14 deletion

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.     

WAGR syndrome and multiple exostoses in a patient with del(11)(p11.2p14.2)

The WAGR syndrome (Wilms' tumour, aniridia, genital anomalies, and mental retardation) is well documented to be associated with a deletion of 11p13. We present a patient with a del(11)(p11.2p14.2) who as well as all the features of WAGR syndrome has multiple exostoses. We suggest that this could be a possible locus for hereditary multiple exostoses.     

Analysis of WAGR deletions and related translocations with gene-specific DNA probes,using FACS-selected cell hybrids

We used the fluorescence-activated cell sorter (FACS) to select a series of somatic cell hybrids with deleted or translocated chromosome 11 segregated from its normal homolog. Analysis of these cell hybrids with gene-specific probes and for cell-surface marker expression has allowed us to order the markers and define a smallest region of overlap (SRO) for deletions associated with the WAGR (Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation) region of chromosome 11. Two translocation breakpoints in 11 p13 (one associated with familial aniridia and one with a sporadic case of congenital renal dysfunction resulting from urethral and ureteral atresia) map within this SRO.     

A FISH approach to defining the extent and possible clinical significance of deletions at the WAGR locus.

Nineteen patients were analysed by fluorescence in situ hybridisation (FISH) with selected 11p13 markers. They were examined because they had either isolated sporadic or familial aniridia, or aniridia with one or more of the WAGR (Wilms' tumour, aniridia, genital anomalies, and mental retardation) syndrome anomalies. The FISH markers from distal 11p13 were cosmids FO2121, PAX6 (aniridia), D11S324, and WT1 (Wilms' tumour predisposition). Two of the patients with isolated aniridia were abnormal, one with an apparently balanced reciprocal 7;11 translocation and an 11p13 breakpoint, which by FISH was shown to be approximately 30 kb distal to the aniridia (PAX6) gene, and the other had a submicroscopic deletion involving part of PAX6 that extended distally for approximately 245 kb. Two patients with aniridia together with other WAGR malformations had deletions involving all four cosmids. One case with aniridia associated with developmental and growth delay had a deletion including FO2121 and PAX6 but not D11S324 and WT1, while in a further case the deletion included all four test cosmids. These studies show that a combined conventional and molecular cytogenetic approach to patients presenting with aniridia is a useful method for differentiating between those with deletions extending into and including WT1 and therefore between those with high and low risks of developing Wilms' tumour.     

Genetics of cancer predisposition and progression

Summary The development of human cancer is a multistep process that entails a progressively more malignant phenotype through the evolution of cellular subsets with increasing numbers of genetic alterations. Here we review the molecular genetics of human cancer predisposition and progression and describe paradigmatic cancer types and cancer syndromes. We also briefly consider the future impact of molecular biology on cancer diagnosis and treatment.Abbreviations APC adenomatous polyposis coli - BWS Beckwith-Wiedemann syndrome - DCC deletion in colorectal cancer - EGFR epidermal growth factor receptor - FAP familial adenomatous polyposis - IGF insulin-like growth factor - LOH loss of heterozygosity - MEN multiple endocrine neoplasia - NF neurofibromatosis - NSCLC non-small-cell lung cancer - RCC renal-cell carcinoma - SCLC small-cell lung cancer - VHL von Hippel-Lindau syndrome - WAGR Wilms' tumor, aniridia, genitourinary anomalies, mental retardation syndrome - WT Wilms' tumor - ZF zinc finger     

Congenital diaphragmatic hernia in WAGR syndrome

Wilms tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is a contiguous gene deletion syndrome involving the Wilms tumor 1 gene (WT1), the paired box gene 6 (PAX6), and possibly other genes on chromosome 11p13. WT1 is required for normal formation of the genitourinary system and the high incidence of Wilms tumor and genitourinary anomalies found in patients with WAGR are attributed to haploinsufficiency of this gene. It has been hypothesized that WT1 also plays an important role in the development of the diaphragm. During mammalian embryonic development, WT1 is expressed in the pleural and abdominal mesothelium that forms part of the diaphragm. Furthermore, mice that are homozygous for a deletion in the mouse homolog of WT1 have diaphragmatic hernias. Case reports describing congenital diaphragmatic hernias in infants with Denys-Drash and Frasier syndromes, both of which can be caused by mutations in WT1, provide additional support for this hypothesis. We report an infant with aniridia, bilateral cryptorchidism, vesicoureteral reflux, and a right-sided Morgagni-type diaphragmatic hernia. G-banded chromosome analysis revealed a deletion of 11p12-p15.1. Breakpoint regions were refined by fluorescence in situ hybridization (FISH) and deletion of the WAGR critical region, including WT1, was confirmed. A review of the medical literature identified a second patient with a deletion of 11p13, a left-sided Bochdalek-type diaphragmatic hernia, and anomalies that suggest a diagnosis of WAGR including bilateral microphthalmia, a small penis, bilateral cryptorchidism, and a hypoplastic scrotum. These cases demonstrate that congenital diaphragmatic hernia can be associated with WAGR syndrome and suggest that deletions of WT1 may predispose individuals to develop congenital diaphragmatic hernia.     

Complete sex reversal in a WAGR syndrome patient

The WAGR contiguous gene deletion syndrome is a combination of Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation. Children with WAGR syndrome invariably have a constitutional chromosomal deletion at 11p13. WT1 haploinsufficiency is associated with a significant risk of Wilms tumor while PAX6 haploinsufficiency lead to aniridia, both genes located in the deleted region. The 46,XY patients with WAGR syndrome are often born with genital abnormalities such as cryptorchidism or hypospadias but more rarely ambiguous genitalia. To our knowledge, complete sex reversal has never been observed in WAGR syndrome patients. Here, we report on the clinical, cytogenetic, and molecular characterization of a child with WAGR syndrome and complete sex reversal. The young girl had female external and internal genitalia with normal uterus and fallopian tubes while the ovaries were not observed. Chromosomal analysis showed a 46,XY,del(11)(p12p14.1) karyotype. A 1-Mb resolution array CGH experiment estimated the size of the interstitial deletion at approximately 10 Mb encompassing WT1 and PAX6. The entire coding regions of WT1 and SRY have been sequenced and no mutation has been identified. Frasier syndrome (FS) and Denys-Drash syndrome (DDS) are two disorders associated with mutations in the WT1 gene. Complete sex reversal is a feature usually present in FS and sometimes in DDS, but until now never observed in WAGR syndrome. The present report suggests that these conditions may be considered as part of the spectrum of disease due to WT1 gene alterations.     

Three patients with hallucal polydactyly and WAGR syndrome, including discordant expression of Wilms tumor in MZ twins

The WAGR contiguous gene deletion syndrome is a combination of Wilms tumor, Aniridia, Genito-urinary abnormalities, and growth and mental retardation which is invariably associated with an 11p13 deletion. We report two monozygotic twins and a third, unrelated patient with WAGR syndrome and additional clinical features not usually associated with WAGR. Both twins had developmental delay, growth deficiency, severe ocular involvement (nystagmus, aniridia, cataracts), atrial septal defect and two uncommon findings: agenesis of the corpus callosum and duplication of the halluces. One twin developed Wilms tumors aged 19 months while her sister remained tumor free by the age of 6.5 years. The singleton patient showed typical WAGR syndrome and preaxial hallucal polydactyly. Molecular cytogenetic studies refined the identification of the extent of the deleted segments, which were not identical in the two families. The two deletions included the PAX6 and WT1 genes as previously reported in typical WAGR patients. The unusual anomalies described in this report, may represent the expression of low penetrant traits associated with haploinsufficency of one or more of the genes present in the deletion (PAX6 is expressed in CNS) or may indicate epistatic influences of modifier genes on the expression of gene(s) present in the WAGR region.     

Molecular analysis of chromosomal rearrangements using pulsed field gel electrophoresis and somatic cell hybrids.

Many human genetic diseases, including some cancers, are characterized by consistent chromosome abnormalities, such as deletions and translocations. Analyses of these mutations often prove crucial to the eventual cloning and characterization of the gene(s) responsible for the disease. Two methods for analyzing these chromosome abnormalities have been developed in recent years: somatic cell hybridization and pulsed field gel electrophoresis (PFGE). Somatic cell hybridization is a technique for segregating an aberrant chromosome from its normal homologue in a cell derived from an unrelated species, which is usually a rodent. Panels of such hybrids dividing a given chromosomal region into increasingly smaller units can be constructed and used specifically to map DNA probes into those units. PFGE can then be used to define precise physical distances between such an array of chromosome abnormalities. Demonstrations of these analytic techniques are presented, using as an example chromosomal abnormalities involving human chromosome band 11p13, the locus for the Wilms' tumor, aniridia, genitourinary abnormality, and mental retardation (WAGR) syndrome.     

Missense mutations in the DNA-binding region and termination codon in PAX6

We have identified nine novel intragenic mutations of the PAX6 gene in 30 patients with aniridia. One patient with Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR syndrome) had deletion of 11p and had lost the paternal PAX6 allele. Two patients had small deletions: a frameshift that should result in early termination of the PAX6 protein, and a frameshift that leads to a termination-site change and run-on into the 3' untranslated region (UTR). The other 27 patients had single base-pair mutations. Four had splicing defects; three had IVS6+1G>A, which was at a mutation hotspot in the PAX6 gene; 10 had premature termination (four 1024C>T [R203X], also at a mutation hotspot); and six had missense mutations. Missense mutation A321T (1378G>A) was a polymorphic change; the other five missense mutations were L46R, C52R, I56T, G73D, and I87K. These five codons are in the PAX6 paired domain and are highly conserved throughout the entire paired family. Seven patients had a mutation in the normal stop codon (TAA). This change leads to run-on into the 3' UTR and is also at a mutation hotspot. All 30 mutations should result in PAX6 haploinsufficiency. No correlation was observed between mutation sites and phenotypes.     

Mutation in the PAX6 gene in twenty patients with aniridia

This is a report on the nature of the mutations in the PAX6 gene in twenty patients with aniridia. Five of the twenty patients had sporadic aniridia with deletions in chromosome 11p13. Three of the five had WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, mental retardation), and the other two had deletions whose breakpoints occurred between the PAX6 and the WT1 genes. Allelic losses at PAX6 were of paternal origin. The remaining fifteen patients with aniridia had intragenic mutations in the PAX6 gene, with mutations found from exon 5 to exon 12. Twelve cases of dysfunctional PAX6 were due to premature termination of the protein by nonsense mutations (five cases), splicing defect (one case), deletion (two cases), deletion-insertions (two cases), and tandem repeat insertions (two cases). One patient (P2) had a PAX6 protein with de novo in-frame deletion of alanine, arginine, and proline at codon positions 37, 38, and 39. These codons are in the paired box region, and codon 38 is in contact with the phosphate group of the sugar-phosphate backbone of the target DNA. Another patient (P8) had a single nucleotide transition at c.1182 (nucleotide number, Genbank accession #M93650, used as in Glaser et al. [1992]), which generated both a missense mutation (Q255H) and a splicing defect. A missense mutation was found at G387E in a third patient (P10). All observed mutations support the notion that haploinsufficiency in PAX6 results in aniridia and associated eye anomalies.     

A 7.5 Mb sequence-ready PAC contig and gene expression map of human chromosome 11p13-p14.1

The region p13 of the short arm of human chromosome 11 has been studied intensely during the search for genes involved in the etiology of the Wilms' tumor, aniridia, genitourinary abnormalities, mental retardation (WAGR) syndrome, and related conditions. The gene map for this region is far from being complete, however, strengthening the need for additional gene identification efforts. We describe the extension of an existing contig map with P1-derived artificial chromosomes (PACs) to cover 7.5 Mb of 11p13-14.1. The extended sequence-ready contig was established by end probe walking and fingerprinting and consists of 201 PAC clones. Utilizing bins defined by overlapping PACs, we generated a detailed gene map containing 20 genes as well as 22 anonymous ESTs which have been identified by searching the RH databases. RH maps and our established gene map show global correlation, but the limits of resolution of the current RH panels are evident at this scale. Initial expression studies on the novel genes have been performed by Northern blot analyses. To extend these expression profiles, corresponding mouse cDNA clones were identified by database search and employed for Northern blot analyses and RNA in situ hybridizations to mouse embryo sections. Genomic sequencing of clones along a minimal tiling path through the contig is currently under way and will facilitate these expression studies by in silico gene identification approaches.     

Pathological and molecular biological aspects of the renal epithelial neoplasms, up-to-date

Renal neoplasms are not necessarily high in frequency, but they are characteristic in their heterogeneity and occasional association with systemic familial tumor syndromes and phacomatoses (e.g. clear cell renal cell carcinoma and von Hippel-Lindau disease, Wilms tumor and aniridia, genitourinary malformation and mental retardation (so-called, WAGR syndrome), and angiomyolipoma and tuberous sclerosis). Physicians and pathologists should take note of these syndromes and associated renal neoplasms because they have provided important clues to elucidate the mechanism of tumorigenesis concerning cancer-suppressor genes. This review aims to present recent classification of renal parenchymal neoplasms based on their molecular biological characteristics, and future problems yet to be clarified.     

Del 11p/aniridia complex. Report of three patients and review of 37 observations from the literature

Three patients (two females, one male) are reported with bilateral aniridia, Wilms' tumor, more or less moderate mental retardation, decreased catalase activity, and del 1 lp13. These and 34 case reports from the literature are discussed with respect to: sex ratio, maternal age, type of chromosomal imbalance and frequency of associated rearrangements, prevalence of aniridia and other eye disorders, predisposition to tumor development, genitourinary anomalies, growth and mental retardation, and catalase involvement. Possible gene relationship within the complex locus and with neighbouring 1 lp genes is discussed.     

The aniridia-Wilms tumor association: The critical role of chromosome band 11p13

The role of del (11)(p13) as a cause of aniridia, with and without Wilms tumor, is strengthened by demonstration of this chromosome aberration in 3 patients: monozygous twin girls, both of whom have aniridia and mental retardation and one of whom has a Wilms tumor; and an unrelated boy with aniridia and ambiguous genitalia. The break points defining the interstitial deletion for the twins are 11p13 and 11p15.1, while for the boy they are 11p1302 and 11p14.1. These patients and their karyotypes substantiate the critical importance of chromosome band 11p13 (or its hemizygous representation) in the development of aniridia and an associated Wilms tumor diathesis, as had been suggested previously (Riccardi VM, Sujansky E, Smith AC, Francke U, (1978): Pediatrics 61, 604-610).     

Catalase determination in various etiologic forms of Wilms' tumor and gonadoblastoma

We have previously mapped the gene coding for catalase to 11p13 by gene dosage analysis. Deletion of this chromosomal region causes aniridia, mental retardation, and predisposition to Wilms' tumor (WT). In the present study, 22 patients with various etiologic forms of WT and/or aniridia were investigated. The catalase (CAT) level and karyotype were examined in order to determine the linkage and the gene ordering on chromosome number 11 of the different loci involved. The CAT concentration was normal in the 19 cases without detectable chromosomal abnormalities.     

Molecular analysis of patients with aniridia in Russian Federation broadens the spectrum of PAX6 mutations

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.