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 report a mutation of UBE2A/HR6A, which encodes a ubiquitin-conjugating enzyme (E2), a member of the ubiquitin proteasome pathway, as the cause of a novel X-linked mental retardation (XLMR) syndrome that affects three males in a two-generation family. A single-nucleotide substitution, c.382C-->T in UBE2A, led to a premature UAG stop codon (Q128X). As a consequence, the predicted polypeptide lacks the 25 C-terminal amino acid residues. The importance of this terminal sequence for UBE2 function is inferred by its conservation in vertebrates and in Drosophila. UBE2A mutations do not appear to significantly contribute to XLMR, since no UBE2A mutations were identified in 15 families with nonsyndromic and 4 families with syndromic idiopathic XLMR previously mapped to intervals encompassing this gene. This is the first description of a mutation in a ubiquitin-conjugating enzyme gene as the cause of a human disease.
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PMID:UBE2A, which encodes a ubiquitin-conjugating enzyme, is mutated in a novel X-linked mental retardation syndrome. 1690 93

By using an in-house bacterial artificial chromosome-based X-tilling array, we detected a 0.4 Mb novel deletion at Xq24 that included UBE2A in a 4-year-old and 10-month-old boy with mental retardation and various other characteristics inherited from his mother; for example, marked developmental delay, synophrys, ocular hypertelorism, esotropia, low nasal bridge, marked generalized hirsutism and seizure. Although additional nine transcripts around UBE2A were also defective, a phenotypic similarity with a recently reported X-linked familial case involving a novel X-linked mental retardation syndrome and a nonsense mutation of UBE2A indicates a functional defect of UBE2A to be responsible for most of the abnormalities in these cases. Because some characteristics, such as congenital heart disease and proximal placement of the thumb, were not described in the family reported previously, suggesting genes other than UBE2A within the deleted region to be responsible for those abnormalities.
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PMID:Novel deletion at Xq24 including the UBE2A gene in a patient with X-linked mental retardation. 2033 84

Recently, a truncating mutation of the UBE2A gene has been observed in a family with X-linked mental retardation (XLMR) (1). The three affected males had similar phenotypes, including seizures, obesity, marked hirsutism and a characteristic facial appearance. Here, we report on two families with a total of seven patients and a clinically very similar syndromic form of XLMR. Linkage analysis was performed in the larger of these families, and screening several positional candidate genes revealed a G23R missense mutation in the UBE2A gene. Subsequent UBE2A screening of a phenotypically similar second family revealed another missense mutation, R11Q, again affecting an evolutionarily conserved amino acid close to the N-terminus of the protein. SIFT and PolyPhen analyses suggest that both mutations are pathogenic, which is supported by their absence in 168 healthy controls. Thus, both missense and truncating mutations can give rise to a specific, syndromic form of XLMR which is identifiable in a clinical setting.
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PMID:Novel missense mutations in the ubiquitination-related gene UBE2A cause a recognizable X-linked mental retardation syndrome. 2041 11

Aberrant connectivity is implicated in many neurological and psychiatric disorders, including Alzheimer's disease and schizophrenia. However, other than a few disease-associated candidate genes, we know little about the degree to which genetics play a role in the brain networks; we know even less about specific genes that influence brain connections. Twin and family-based studies can generate estimates of overall genetic influences on a trait, but genome-wide association scans (GWASs) can screen the genome for specific variants influencing the brain or risk for disease. To identify the heritability of various brain connections, we scanned healthy young adult twins with high-field, high-angular resolution diffusion MRI. We adapted GWASs to screen the brain's connectivity pattern, allowing us to discover genetic variants that affect the human brain's wiring. The association of connectivity with the SPON1 variant at rs2618516 on chromosome 11 (11p15.2) reached connectome-wide, genome-wide significance after stringent statistical corrections were enforced, and it was replicated in an independent subsample. rs2618516 was shown to affect brain structure in an elderly population with varying degrees of dementia. Older people who carried the connectivity variant had significantly milder clinical dementia scores and lower risk of Alzheimer's disease. As a posthoc analysis, we conducted GWASs on several organizational and topological network measures derived from the matrices to discover variants in and around genes associated with autism (MACROD2), development (NEDD4), and mental retardation (UBE2A) significantly associated with connectivity. Connectome-wide, genome-wide screening offers substantial promise to discover genes affecting brain connectivity and risk for brain diseases.
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PMID:Genome-wide scan of healthy human connectome discovers SPON1 gene variant influencing dementia severity. 2347 85

We present array comparative genomic hybridization (aCGH) characterization of a novel Xq21.1-25 duplication in a 2-year-old girl with facial dysmorphism, mental retardation and short stature. Analysis of aCGH results revealed a 47,232kb duplication region that harbored 231 RefSeq genes, including 32 OMIM genes. Ten genes (i.e., ZNF711, SRPX2, RAB40AL, MID2, ACSL4, PAK3, UBE2A, UPF3B, CUL4B, and GRIA3) in the duplication interval have been associated with mental retardation. We discuss the genotype-phenotype correlation in this case. Our case provides evidence for an association of mental retardation with X chromosome duplication.
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PMID:A novel 47.2 Mb duplication on chromosomal bands Xq21.1-25 associated with mental retardation. 2595 75

Chromosomal microdeletion syndromes present with a wide spectrum of clinical phenotypes that depend on the size and gene content of the affected region. In a healthy carrier, epigenetic mechanisms may compensate for the same microdeletion, which may segregate through several generations without any clinical symptoms until the epigenetic modifications no longer function. We report 2 novel cases of Xq24 microdeletions inherited from mothers with extremely skewed X-chromosome inactivation (sXCI). The first case is a boy presenting with X-linked mental retardation, Nascimento type, due to a 168-kb Xq24 microdeletion involving 5 genes (CXorf56, UBE2A, NKRF, SEPT6, and MIR766) inherited from a healthy mother and grandmother with sXCI. In the second family, the presence of a 239-kb Xq24 microdeletion involving 3 additional genes (SLC25A43, SLC25A5-AS1, and SLC25A5) was detected in a woman with sXCI and a history of recurrent pregnancy loss with a maternal family history without reproductive wastages or products of conception. These cases provide evidence that women with an Xq24 microdeletion and sXCI may be at risk for having a child with intellectual disability or for experiencing a pregnancy loss due to the ontogenetic pleiotropy of a chromosomal microdeletion and its incomplete penetrance modified by sXCI.
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PMID:Delineation of Clinical Manifestations of the Inherited Xq24 Microdeletion Segregating with sXCI in Mothers: Two Novel Cases with Distinct Phenotypes Ranging from UBE2A Deficiency Syndrome to Recurrent Pregnancy Loss. 3248 17