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)

Cornelia de Lange syndrome (CdLS) is a multisystem developmental disorder characterized by facial dysmorphism, growth and mental retardation, microcephaly, and various malformations. Heterozygous mutations in the NIPBL gene have been detected in approximately 45% of affected individuals. Recently, a second CdLS gene, mapping to the X chromosome, has been identified: SMC1L1 (structural maintenance of chromosomes 1-like 1; or SMC1A). In order to estimate the incidence and refine the clinical presentation of X-linked CdLS, we have screened a series of 11 CdLS boys carrying no NIPBL anomaly. We have identified two novel de novo SMC1L1 missense mutations (c.587G>A [p.Arg196His] and c.3254A>G [p.Tyr1085Cys]). Our results confirm that SMC1L1 mutations cause CdLS and support the view that SMC1L1 accounts for a significant fraction of boys with unexplained CdLS. Furthermore, we suggest that SMC1L1 mutations have milder effects than NIPBL mutations with respect to pre- and postnatal growth retardation and associated malformations. If confirmed, these data may have important implications for directing mutation screening in CdLS.
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PMID:Incidence and clinical features of X-linked Cornelia de Lange syndrome due to SMC1L1 mutations. 1722 63

Mutations in the cohesin regulators NIPBL and ESCO2 are causative of the Cornelia de Lange syndrome (CdLS) and Roberts or SC phocomelia syndrome, respectively. Recently, mutations in the cohesin complex structural component SMC1A have been identified in two probands with features of CdLS. Here, we report the identification of a mutation in the gene encoding the complementary subunit of the cohesin heterodimer, SMC3, and 14 additional SMC1A mutations. All mutations are predicted to retain an open reading frame, and no truncating mutations were identified. Structural analysis of the mutant SMC3 and SMC1A proteins indicate that all are likely to produce functional cohesin complexes, but we posit that they may alter their chromosome binding dynamics. Our data indicate that SMC3 and SMC1A mutations (1) contribute to approximately 5% of cases of CdLS, (2) result in a consistently mild phenotype with absence of major structural anomalies typically associated with CdLS, and (3) in some instances, result in a phenotype that approaches that of apparently nonsyndromic mental retardation.
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PMID:Mutations in cohesin complex members SMC3 and SMC1A cause a mild variant of cornelia de Lange syndrome with predominant mental retardation. 1727 69

Cornelia de Lange syndrome (CdLS) (OMIM #122470, #300590 and #610759) is a dominant genetic disorder with multiple organ system abnormalities which is classically characterized by typical facial features, growth and mental retardation, upper limb defects, hirsutism, gastrointestinal and other visceral system involvement. Mutations in three cohesin proteins, a key regulator of cohesin, NIPBL, and two structural components of the cohesin ring SMC1A and SMC3, etiologically account for about 65% of individuals with CdLS. Cohesin controls faithful chromosome segregation during the mitotic and meiotic cell cycles. Multiple proteins in the cohesin pathway are also involved in additional fundamental biological events such as double-strand DNA break repair and long-range regulation of transcription. Moreover, chromosome instability was recently associated with defective sister chromatid cohesion in several cancer studies, and an increasing number of human developmental disorders is being reported to result from disruption of this pathway. Here, we will discuss the human disorders caused by alterations of cohesin function (termed 'cohesinopathies'), with an emphasis on the clinical manifestations of CdLS and mechanistic studies of the CdLS-related proteins.
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PMID:Cornelia de Lange syndrome, cohesin, and beyond. 1979 4

Cornelia de Lange syndrome (CdLS) is a multiple congenital anomaly/mental retardation syndrome, characterized by distinctive facial features, generalized hirsutism, growth and cognitive dysfunction, microcephaly and limb abnormalities. Currently mutations of three different genes, NIPBL, SMC1A, and SMC3, are known to be related to the CdLS phenotype with an overall detection rate of about 50%. Few data are available regarding the level of autonomy in everyday life of CdLS patients. Due to the collaboration of the Italian parents' support group, we collected information regarding clinical and behavioral problems and everyday abilities of 45 CdLS patients between 13 and 39 years, using a specific multi-item questionnaire. To better analyze clinical information we divided our patients into three groups according to age: 13-20, 21-29, and over 30 years. Data from clinical, malformative and behavioral problems were not significantly different from those described for CdLS patients. Regarding personal autonomies this study showed the significant limitations of these individuals. It is interesting to observe that patients between 21 and 29 years, showed the best performance, while those over 30 had more severe difficulties. We suggest that these data be interpreted as a minimum level of autonomy achievable for CdLS adolescent/young adults, as the level of care, rehabilitation and stimulation of these patients has increased in the last 30 years.
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PMID:Clinical problems and everyday abilities of a group of Italian adolescent and young adults with Cornelia de Lange syndrome. 1987

Cornelia de Lange syndrome (CdLS) is a rare, congenital syndrome characterized by growth retardation, dysmorphic face, mental retardation and limb reduction defects. Clinical manifestations of CdLS can be extremely variable. Mutations in NIPBL, SMC1A and SMC3 genes, encoding for a regulator and two subunits of the cohesin complex, respectively, are found in 60-65% of CdLS patients. We report on a male with CdLS who is mosaic for the c.2827delA mutation in the NIPBL gene. Allele quantitation by pyrosequencing showed the presence of the mutation in about 10% and 33% of DNA samples from peripheral blood and buccal smears, respectively. The patient shows a complex phenotype: growth and psychomotor retardation are characteristic of the severe forms of CdLS, while the absence of severe limb reduction defects and major malformations are typical of the mild phenotype. He also has depigmentation areas following Blashko lines, an unusual finding in CdLS, which has been associated with mosaicism in other genetic conditions. This case represents the first evidence of somatic mosaicism in CdLS and explains the mild phenotype in the patient as compared to that predicted by a truncating mutation. Besides confirming the clinical and genetic heterogeneity of CdLS, this case also raises the likely underestimated mutation rate of known genes and points to the complexity of addressing genotype-phenotype correlations.
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PMID:Somatic mosaicism in Cornelia de Lange syndrome: a further contributor to the wide clinical expressivity? 2033 78

Cornelia de Lange syndrome (CdLS) (OMIM # 122470, #300590 and #610759) is an autosomal dominant disorder that is classically characterized by typical facial features, growth and mental retardation, upper limb defects, hirsutism, gastrointestinal and other visceral system involvement. Heterozygous mutations in the cohesin regulator, NIPBL, or the cohesin structural components SMC1A and SMC3, have been identified in approximately 65% of individuals with CdLS. Cohesin regulates sister chromatid cohesion during the mitotis and meiosis. In addition, cohesin has been demonstrated to play a critical role in the regulation of gene expression. Furthermore, multiple proteins in the cohesin pathway are also involved in additional fundamental biological events such as double strand DNA break repair, chromatin remodeling and maintaining genomic stability. Here, we will discuss the biology ofcohesin and its associated factors, with emphasis on the clinical manifestations of CdLS and mechanistic studies of the CdLS related proteins.
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PMID:Cornelia de Lange syndrome. 2068

Cornelia de Lange syndrome (CdLS) is a dominantly inherited developmental disorder characterized by distinctive facial features, mental retardation, and upper limb defects, with the involvement of multiple organs and systems. To date, mutations have been identified in five genes responsible for CdLS: NIPBL, SMC1A, SMC3, RAD21, and HDAC8. Here, we present a clinical and molecular characterization of five unrelated Chinese patients whose clinical presentation is consistent with that of CdLS. There were no chromosomal abnormalities in the five children. In three patients, DNA sequencing revealed a previously reported frameshift mutation c.2479delA (p.Arg827GlyfsX20), and two novel mutations including a heterozygous mutation c.6272 G>T (p.Cys2091Phe) and a frameshift mutation c.1672delA (p.Thr558LeufsX7) in NIPBL. For the remaining patients, large deletions and/or duplications within the NIPBL gene were excluded as playing a role in the pathogenesis, by Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. These findings broaden the mutation spectrum of NIPBL and further our understanding of the diverse and variable effects of NIPBL mutations on CdLS.
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PMID:Two novel NIPBL gene mutations in Chinese patients with Cornelia de Lange syndrome. 2544 6

Genetic variants within components of the cohesin complex (NIPBL, SMC1A, SMC3, RAD21, PDS5, ESCO2, HDAC8) are believed to be responsible for a spectrum of human syndromes known as "cohesinopathies" that includes Cornelia de Lange Syndrome (CdLS). CdLS is a multiple malformation syndrome affecting almost any organ and causing severe developmental delay. Cohesinopathies seem to be caused by dysregulation of specific developmental pathways downstream of mutations in cohesin components. However, it is still unclear how mutations in different components of the cohesin complex affect the output of gene regulation. In this study, zebrafish embryos and SMC1A-mutated patient-derived fibroblasts were used to analyze abnormalities induced by SMC1A loss of function. We show that the knockdown of smc1a in zebrafish impairs neural development, increases apoptosis, and specifically down-regulates Ccnd1 levels. The same down-regulation of cohesin targets is observed in SMC1A-mutated patient fibroblasts. Previously, we have demonstrated that haploinsufficiency of NIPBL produces similar effects in zebrafish and in patients fibroblasts indicating a possible common feature for neurological defects and mental retardation in cohesinopathies. Interestingly, expression analysis of Smc1a and Nipbl in developing mouse embryos reveals a specific pattern in the hindbrain, suggesting a role for cohesins in neural development in vertebrates.
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PMID:CyclinD1 Down-Regulation and Increased Apoptosis Are Common Features of Cohesinopathies. 2620 33

Cornelia de Lange syndrome (CdLS) is a clinically and genetically heterogeneous congenital anomaly. Mutations in the NIPBL gene account for a half of the affected individuals. We describe a family with CdLS carrying a novel pathogenic variant of the SMC1A gene identified by exome sequencing. The proband was a 3-yr-old boy presenting with a developmental delay. He had distinctive facial features without major structural anomalies and tested negative for the NIPBL gene. His younger sister, mother, and maternal grandmother presented with mild mental retardation. By exome sequencing of the proband, a novel SMC1A variant, c.3178G>A, was identified, which was expected to cause an amino acid substitution (p.Glu1060Lys) in the highly conserved coiled-coil domain of the SMC1A protein. Sanger sequencing confirmed that the three female relatives with mental retardation also carry this variant. Our results reveal that SMC1A gene defects are associated with milder phenotypes of CdLS. Furthermore, we showed that exome sequencing could be a useful tool to identify pathogenic variants in patients with CdLS.
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PMID:Novel pathogenic variant (c.3178G>A) in the SMC1A gene in a family with Cornelia de Lange syndrome identified by exome sequencing. 2635 54

Robert syndrome (RBS) and Cornelia de Lange syndrome (CdLS) are human developmental disorders characterized by craniofacial deformities, limb malformation and mental retardation. These birth defects are collectively termed cohesinopathies as both arise from mutations in cohesion genes. CdLS arises due to autosomal dominant mutations or haploinsufficiencies in cohesin subunits (SMC1A, SMC3 and RAD21) or cohesin auxiliary factors (NIPBL and HDAC8) that result in transcriptional dysregulation of developmental programs. RBS arises due to autosomal recessive mutations in cohesin auxiliary factor ESCO2, the gene that encodes an N-acetyltransferase which targets the SMC3 subunit of the cohesin complex. The mechanism that underlies RBS, however, remains unknown. A popular model states that RBS arises due to mitotic failure and loss of progenitor stem cells through apoptosis. Previous findings in the zebrafish regenerating fin, however, suggest that Esco2-knockdown results in transcription dysregulation, independent of apoptosis, similar to that observed in CdLS patients. Previously, we used the clinically relevant CX43 to demonstrate a transcriptional role for Esco2. CX43 is a gap junction gene conserved among all vertebrates that is required for direct cell-cell communication between adjacent cells such that cx43 mutations result in oculodentodigital dysplasia. Here, we show that morpholino-mediated knockdown of smc3 reduces cx43 expression and perturbs zebrafish bone and tissue regeneration similar to those previously reported for esco2 knockdown. Also similar to Esco2-dependent phenotypes, Smc3-dependent bone and tissue regeneration defects are rescued by transgenic Cx43 overexpression, suggesting that Smc3 and Esco2 cooperatively act to regulate cx43 transcription. In support of this model, chromatin immunoprecipitation assays reveal that Smc3 binds to a discrete region of the cx43 promoter, suggesting that Esco2 exerts transcriptional regulation of cx43 through modification of Smc3 bound to the cx43 promoter. These findings have the potential to unify RBS and CdLS as transcription-based mechanisms.
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PMID:Cohesin mediates Esco2-dependent transcriptional regulation in a zebrafish regenerating fin model of Roberts Syndrome. 2908 13


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