Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A survey carried out to detect children with aniridia/Wilms's tumour syndrome identified 8 living and 3 dead children. The incidence of aniridia was found to be 1 in 43 among Wilms's tumour patients in the UK. The clinical features included complete bilaterial aniridia, cataracts, glaucoma, mental retardation, hyperkinesis, hypospadias, and undescended testes. A high incidence of bilateral tumours (36%), male sex, presentation at a young age, and advanced maternal age appeared to be associated with the syndrome. The 8 living children each had a deletion on the short arm of chromosome 11. In contrast, although 2 patients with sporadic aniridia without Wilms's tumour had other malformations, neither had genitourinary anomalies, and the only additional problems in patients with familial aniridia were cataracts. Among 49 children with Wilms's tumour without aniridia ony one had bilateral tumours. No chromosome abnormalities were detected in patients with familial aniridia, nor were they detected in patients with Wilms's tumour without aniridia or in those with sporadic aniridia without Wilms's tumour. While many infants with the Wilms's tumour/aniridia syndrome are clinically diagnosable at birth, chromosome analysis using the elongated chromosome method is especially valuable to confirm the diagnosis in girls with sporadic aniridia and in boys who lack the genitourinary malformations. The presence of an 11p13 deletion confirms the diagnosis of the Wilms's tumour/aniridia syndrome and indicates a very high risk for the development of Wilms's tumour.
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PMID:Wilms's tumour and aniridia: clinical and cytogenetic features. 628 58

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.
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PMID:Catalase determination in various etiologic forms of Wilms' tumor and gonadoblastoma. 630 58

Non-random tumour-specific chromosomal abnormalities have been observed in cells of many different human tumours. In Wilms' tumour (WT) and retinoblastoma, a chromosomal deletion occurs germinally or somatically and has been considered an important step in tumour development. One class of potential cellular transforming genes comprises the cellular homologues of the transforming genes of highly oncogenic retroviruses. A remarkable concordance between the chromosomal location of human cellular oncogenes and the breakpoints involved in acquired chromosomal translocations is becoming apparent in various cancers: the oncogenes c-mos, c-myc and c-abl are located at the breakpoints that occur in acute myeloblastic leukaemia, Burkitt's lymphoma and chronic myelocytic leukaemia respectively. Thus when the oncogene c-Ha-ras1 was localized to the short arm of human chromosome 11 (refs 6-8; region 11p11 leads to p15 and not 11p13 as stated in ref. 5), it was proposed as a possible aetiological agent in the aniridia-WT association (AWTA) that results from a deletion of 11p13 (although a transforming gene recently isolated from a WT cell line (G401) was shown not to be homologous to either c-Ha-ras or c-Ki-ras9). We have now looked for deletion or rearrangement of c-Ha-ras1 in the DNA from four subjects with del(11p13)-associated predisposition to Wilms' tumour, aniridia, genitourinary abnormalities and mental retardation. We report here that in no case is c-Ha-ras1 deleted, and we have further refined its location to 11p15.1 leads to 11p15.5. On the basis of enzyme studies and direct gene dosage determination for c-Ha-ras1 and beta-globin in neoplastic and non-neoplastic tissues from one patient, we conclude that deletion of the normal counterpart of 11p cannot account for the development of the tumour.
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PMID:c-Ha-ras1 is not deleted in aniridia-Wilms' tumour association. 631 28

An apparently balanced de novo constitutional translocation (7;13) (q36;q13) was detected on peripheral lymphocytes and fibroblasts of a 14-month-old boy. The patient presented a facial dysmorphism with hydrocephaly and mental retardation associated with a Wilms' tumor. A pure coincidence of random association cannot be ruled out but one can equally assert the plausibility of a minimal unnoticed deletion or a position effect.
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PMID:Wilms' tumor, malformative syndrome, mental retardation and de novo constitutional translocation, t(7;13)(q36;q13). 632 Nov 91

Gene dosage effects for catalase (CAT) were studied in two unrelated patients with an interstitial deletion involving 11p13 to determine precisely the sites of the genes for CAT and the Wilms tumor--aniridia, genitourinary abnormalities, and mental retardation triad (WAGR) in the 11p13 band. Case 1 had the aniridia-Wilms tumor association, and case 2 showed the AGR triad. The karyotypes identified by high resolution banding techniques were 46,XY,del(11)(pter----p13::p11.11----qter) for case 1 and 46,XY,t(2;17)(q23;q25),del(11)(pter----p13::p11.2----qter) for case 2. In both cases, the distal breakpoints of the deleted chromosomes 11 appeared to have occurred on the middle portion of 11p13 (11p1305----p1306). The level of erythrocyte CAT activities in case 1 was reduced (47% of normal), while that in case 2 was normal. The results suggested not only that both the CAT and WAGR should be mapped to chromosome region 11p1305----p1306, but also that in this region the CAT locus is more distally placed than the WAGR locus. Because of the proximity of the two gene loci, assays of erythrocyte CAT may be useful to identify a submicroscopic deletion in some patients with sporadic aniridia and to predict a risk of developing Wilms tumor.
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PMID:Regional mapping of catalase and Wilms tumor--aniridia, genitourinary abnormalities, and mental retardation triad loci to the chromosome segment 11p1305----p1306. 632 23

One of the most provocative findings in tumour biology is the relationship between chromosomal changes and embryonal cancers in children. For example, children with the rare paediatric syndrome AGR triad (aniridia, genito-urinary abnormalities and mental retardation) often develop Wilms' tumours at a very early age and carry a germ-line deletion on the short arm of chromosome 11 (11p13). It has been suggested that the germ-line deletion 11p is the first of two or more steps to cancer in AGR children. If this were true, one might expect a similar deletion to arise somatically in the far more common isolated Wilms' tumours of children without AGR, as suggested by Knudson from epidemiological data. However, a chromosomal deletion on 11p was observed in only two of five such cases, while it was absent or seen inconsistently in others. We have now used a molecular genetic approach to determine whether Wilms' tumour cells possess somatic alterations at 11p loci. We have found somatic deletions of specific genes in four of six Wilms' tumours. Surprisingly, in all four cases, the deletions were associated with duplications leading to homozygosity of the non-deleted alleles in the tumour cells. As analogous observations were recently reported in retinoblastoma, the genetic events reported here may underlie the development of many such embryonal tumours in children.
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PMID:Somatic deletion and duplication of genes on chromosome 11 in Wilms' tumours. 632 39

Two unrelated patients with clinical features of 11p13 deletion syndrome, 3 years old and 3 months old, are reported. The clinical features of the patients included mental retardation, aniridia, nystagmus, blepharophimosis, and genitourinary abnormalities. Both patients were apparently free from Wilms' tumor and gonadoblastoma. Prometaphase banding analyses revealed a 46,XY,del(11)(p1300p1500) karyotype in one patient and 46,XX,dir ins(11;2)(p13;q12q23) in the other. Catalase activities in the erythrocytes in the two patients were respectively 65% and 56% of those of normal controls, close to the expected values in hemizygosity of the catalase gene. These findings confirmed a close linkage of the gene for catalase and those for the aniridia--Wilm's tumor or gonadoblastoma complex.
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PMID:Chromosome abnormalities involving 11p13 and low erythrocyte catalase activity. 710 75

Wilms' tumor is a childhood nephroblastoma that is postulated to arise through the inactivation of a tumor suppressor gene by a two-hit mechanism. A candidate 11p13 Wilms' tumor gene, WT1, has been cloned and shown to encode a zinc finger protein. Patients with the WAGR syndrome (Wilm's tumor, aniridia, genitourinary abnormalities, and mental retardation) have a high risk of developing Wilms' tumor and they carry constitutional deletions of one chromosome 11 allele encompassing the WT1 gene. Analysis of the remaining WT1 allele in a Wilms' tumor from a WAGR patient revealed the deletion of a single nucleotide in exon 7. This mutation likely played a key role in tumor formation, as it prevents translation of the DNA-binding zinc finger domain that is essential for the function of the WT1 polypeptide as a transcriptional regulator.
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PMID:Homozygous inactivation of WT1 in a Wilms' tumor associated with the WAGR syndrome. 768 65

The combined use of qualitative and quantitative analysis of 11p13 polymorphic markers together with chromosomal in situ suppression hybridization (CISS) with biotin labeled probes mapping to 11p allowed us to characterize a complex rearrangement segregating in a family. We detected a pericentric intrachromosomal insertion responsible for recurrence of del(11)(p13p14) in the family: an insertion of brand 11p13-p14 carrying the genes for predisposition to Wilms' tumor, WT1, and for aniridia, AN2, into the long arm of chromosome 11 in 11q13-q14. Asymptomatic balanced carriers were observed over three generations. Classical cytogenetics had failed to detect this anomaly in the balanced carriers, who were first considered to be somatic mosaics for del(11)(p13). Two of these women gave birth to children carrying a deleted chromosome 11, most likely resulting from the loss of the 11p13 band inserted in 11q. Although in both cases the deletion encompassed exactly the same maternally inherited markers, there was a wide variation in clinical expression. One child, with the karyotype 46,XY, del(11)(p13p14), presented the full-blown WAGR syndrome with aniridia, mental retardation, Wilms' tumor, and pseudohermaphroditism, but also had proteinuria and glomerular sclerosis reminiscent of Drash syndrome. In contrast, the other one, a girl with the karyotype 46,XX,del(11)(p13), only had aniridia. Although a specific set of mutational sites has been observed in Drash patients, these findings suggest that the loss of one copy of the WT1 gene can result in similar genital and kidney abnormalities.
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PMID:Pericentric intrachromosomal insertion responsible for recurrence of del(11)(p13p14) in a family. 768 57

The Wilms tumour (WT1) gene was first localized through its deletion in individuals with the WAGR syndrome (Wilms tumour, aniridia, genitourinary abnormalities and mental retardation). Such individuals have a 30-50% lifetime risk of developing Wilms tumour and carry constitutional interstitial deletions of chromosome 11p13, including the WT1 gene. Second primary tumours occurring in such individuals might also be related to their genetic predisposition to cancer, as shown for hereditary retinoblastoma. We have found a mutation in the zinc finger region of the remaining WT1 allele in a case of acute myeloid leukaemia developing in a Wilms tumour survivor with the WAGR syndrome. This mutation would be predicted to disrupt DNA binding by this developmentally regulated transcription factor. This finding implicates the WT1 gene in the regulation of myelopoiesis and suggests that WT1 mutations may be found in some sporadic leukaemias.
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PMID:The Wilms tumour (WT1) gene is mutated in a secondary leukaemia in a WAGR patient. 783 22


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