Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We observed a family in which two boys were diagnosed with Alport syndrome, elliptocytosis, and mental retardation and carried a large deletion of the Xq22.3-q23 region, encompassing the COL4A5 gene. This suggests the possibility of a new contiguous gene syndrome. In an attempt to characterize the genes contributing to this complex phenotype, we have isolated a gene encoding a new long-chain acyl-CoA synthetase (FACL4 or LACS4) from the region deleted in these patients. Among several ESTs identified by searching the human gene map database maintained at the National Center for Biotechnology Information, using the map position as a query, only one was deleted in the patients. RACE products containing the entire ORF were subsequently generated. Northern blot analysis showed a 5-kb mRNA expressed in several tissues except for liver and lung. Brain shows a longer transcript, possibly reflecting the use of a brain-specific upstream ATG start codon. FACL4 encodes a predicted protein product of 670 amino acids (711 in brain), with a remarkable level of conservation compared to the rat acyl-CoA synthetases ACS4 and brain-specific ACS3 protein sequences. We are investigating the possibility that the absence of this enzyme may play a role in the development of mental retardation or other signs associated with Alport syndrome in the family.
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PMID:FACL4, a new gene encoding long-chain acyl-CoA synthetase 4, is deleted in a family with Alport syndrome, elliptocytosis, and mental retardation. 948 Jul 48

We describe a family with four members, a mother, two sons, and a daughter, who show clinical features consistent with X linked Alport syndrome. The two males presented with additional features including mental retardation, dysmorphic facies with marked midface hypoplasia, and elliptocytosis. The elliptocytosis was not associated with any detectable abnormalities in red cell membrane proteins; red cell membrane stability and rigidity was normal on ektacytometry. Molecular characterisation suggests a submicroscopic X chromosome deletion encompassing the entire COL4A5 gene. We propose that the additional abnormalities found in the affected males of this family are attributable to deletion or disruption of X linked recessive genes adjacent to the COL4A5 gene and that this constellation of findings may represent a new X linked contiguous gene deletion syndrome.
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PMID:Alport syndrome, mental retardation, midface hypoplasia, and elliptocytosis: a new X linked contiguous gene deletion syndrome? 959 18

We describe a de novo dup 17p11 in a boy with Alport syndrome, mild mental retardation, and minor anomalies. Combining classical and molecular cytogenetics analyses, the karyotype was defined as 46,XY.ish dup (17)(p11.2p11.2)(D17S29++,D17S379+). Alport syndrome is associated with mutations in the type IV alpha chain collagen gene, however, no known collagen-related gene is currently mapped to 17p11. Duplications involving 17p11.2 have been reported in Charcot-Marie-Tooth disease, Dejerine-Sottas syndrome, and in a few sporadic patients with mental retardation and minor anomalies, however, no significant clinical similarity was found among these cases and the propositus. Further studies may clarify the meaning of the association between Alport syndrome and duplications of DNA sequences mapped at 17p11.2.
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PMID:A dup(17)(p11.2p11.2) detected by fluorescence in situ hybridization in a boy with Alport syndrome. 993 86

We recently described a novel contiguous gene deletion syndrome (AMME) in Xq22.3 that includes Alport syndrome (A), mental retardation (M), midface hypoplasia (M), and elliptocytosis (E). While the Alport syndrome is due to deletion of the COL4A5 gene, no other genes are known in the region with the exception of our recent finding of the FACL4 gene. In our effort to isolate additional genes from the deleted region, we have identified the gene named AMMECR1 (Alport syndrome, mental retardation, midface hypoplasia, and elliptocytosis chromosomal region gene 1). RACE experiments and screening of cDNA libraries enabled us to obtain the entire ORF of the gene (1002 bp) followed by about 2 kb of 3'UTR. AMMECR1 is composed of six exons, shows a ubiquitous 6.5-kb transcript, and codes for a protein with a molecular mass of 35.5 kDa. Sequence analysis revealed that this gene is conserved in several species ranging from Caenorhabditis elegans and yeast to micro-organisms. Exon 2 of AMMECR1 encodes a domain consisting of six amino acids identically conserved throughout the course of evolution and whose function is as yet unknown. Analysis of the predicted protein product using ExPAsy tools raises the possibility that the gene may code for a regulatory factor potentially involved in the development of AMME contiguous gene deletion syndrome.
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PMID:Identification and characterization of a highly conserved protein absent in the Alport syndrome (A), mental retardation (M), midface hypoplasia (M), and elliptocytosis (E) contiguous gene deletion syndrome (AMME). 1004 89

The contiguous gene deletion syndrome AMME is characterized by Alport syndrome, midface hypoplasia, mental retardation and elliptocytosis and is caused by a deletion in Xq22.3, comprising several genes including COL4A5, FACL4 and AMMECR1. We have now cloned the murine Facl4 and Ammecr1 genes and have mapped both novel murine genes to mouse chromosome X band F1-F3. The murine and human orthologs show 96.5% (FACL4) and 95.2% (AMMECR1) identity at the amino acid level, with conservation of the respective putative subcellular localization signals. Our results show that Facl4 and Ammecr1 are the true murine orthologs of the human genes. Furthermore, the mapping of Facl4 and Ammecr1 to MmuXF1-F3 suggests that this subinterval is orthologous, at least for a portion of Xq22. 3.
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PMID:Identification and characterization of mouse orthologs of the AMMECR1 and FACL4 genes deleted in AMME syndrome: orthology of Xq22.3 and MmuXF1-F3. 1082 4

X-linked mental retardation (XLMR) is an inherited condition that causes failure to develop cognitive abilities, owing to mutations in a gene on the X chromosome. The latest XLMR update lists up to 136 conditions leading to 'syndromic', or 'specific', mental retardation (MRXS) and 66 entries leading to 'nonspecific' mental retardation (MRX). For 9 of the 66 MRX entries, the causative gene has been identified. Our recent discovery of the contiguous gene deletion syndrome ATS-MR (previously known as Alport syndrome, mental retardation, midface hypoplasia, elliptocytosis, OMIM #300194), characterized by Alport syndrome (ATS) and mental retardation (MR), indicated Xq22.3 as a region containing one mental retardation gene. Comparing the extent of deletion between individuals with ATS-MR and individuals with ATS alone allowed us to define a critical region for mental retardation of approximately 380 kb, containing four genes. Here we report the identification of two point mutations, one missense and one splice-site change, in the gene FACL4 in two families with nonspecific mental retardation. Analysis of enzymatic activity in lymphoblastoid cell lines from affected individuals of both families revealed low levels compared with normal cells, indicating that both mutations are null mutations. All carrier females with either point mutations or genomic deletions in FACL4 showed a completely skewed X-inactivation, suggesting that the gene influences survival advantage. FACL4 is the first gene shown to be involved in nonspecific mental retardation and fatty-acid metabolism.
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PMID:FACL4, encoding fatty acid-CoA ligase 4, is mutated in nonspecific X-linked mental retardation. 1188 65

To investigate whether submicroscopic chromosomal deletions or duplications can be causative of unclear syndromic nephropathies, we analyzed ten patients with congenital abnormalities of the kidney and urinary tract or glomerulopathies combined with important extrarenal anomalies by whole-genome array-based comparative genomic hybridization. In a 14-year-old girl presenting with hematuria, proteinuria, mental retardation (MR), sensorineural hearing loss, dysmorphisms, and epilepsy, we detected a microdeletion in chromosome Xq22.3-q23. This deletion was verified and characterized by fluorescence in situ hybridization and multiplex ligation-dependent probe amplification analyses, found to be de novo, uniallelic and 3.3 Mb in size. Electron microscopy of a kidney biopsy showed glomerular basement membrane thinning and segmental splitting of the lamina densa compatible with Alport syndrome. Cranial magnetic resonance and diffusion tensor imaging detected a severe neuronal migration disorder with double cortex formation and pronounced reduction of the fronto-occipital tract system. Thus, in one of ten patients with unclear syndromic nephropathies we identified a previously undescribed contiguous gene syndrome at Xq22.3-q23. The microdeletion contains the X-linked Alport syndrome gene COL4A5, the MR genes FACL4 and PAK3, and parts of the X-chromosomal lissencephaly gene DCX associated with double cortex formation in girls, MR, and epilepsy. The phenotype in our patient combines features of the Alport-MR contiguous gene syndrome with lissencephaly.
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PMID:Array-CGH in unclear syndromic nephropathies identifies a microdeletion in Xq22.3-q23. 1944 85

In this study, we report a family with X-linked recessive syndrome caused by mutated AMMECR1 and characterized by elliptocytosis with or without anemia, midface hypoplasia, proportionate short stature and hearing loss. Recently, mutations in AMMECR1 were reported in two maternal half-brothers, presenting with nephrocalcinosis, midface hypoplasia and, in one of the siblings, deafness and elliptocytosis. AMMECR1 gene is localized in the critical region of contiguous deletion syndrome on Xq22.3 implicated in Alport syndrome, mental retardation, midface hypoplasia, and elliptocytosis (AMME complex). Interestingly, alternative splicing of exon 2, the same exon harboring the truncating mutation, was observed in the proband and in his unaffected mother. Alternative splicing of this exon is predicted to lead to an in-frame deletion. We provide further evidence that mutated AMMECR1 gene is responsible for this clinically recognizable X-linked condition with variable expressivity.
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PMID:X-linked elliptocytosis with impaired growth is related to mutated AMMECR1. 2917 31