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)

Nance-Horan syndrome (NHS) is a rare X-linked condition comprising congenital cataract with microcornea, distinctive dental, and evocative facial anomalies. Intellectual handicap was mentioned in seven published NHS patients. We performed a clinical study focused on psychomotor development, intellectual abilities, and behavior in 13 affected males in four NHS families, and present the results of a neuropsychological evaluation in 7 of them. Our study confirms that mental retardation (MR) can be a major component of the NHS. Combining our data with those from the literature leads to a frequency of MR in NHS of around 30%. In most cases, MR is mild or moderate (80%) and not associated with motor delay. Conversely, a profound mental handicap associated with autistic traits may be observed. MR has intra- and inter-familial variability but does not appear to be expressed in carriers. Awareness of MR in NHS may be of importance in the management of the patients, especially in terms of education. Cloning and characterization of the gene and analysis of mutations will be an important step towards understanding the molecular basis of mental deficiency in NHS, and in delineation from the other XLMR conditions at Xp22.
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PMID:Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families. 926 1

Nance-Horan syndrome (NHS) is an X-linked condition characterised by congenital cataracts, dental abnormalities, dysmorphic features, and mental retardation in some cases. Previous studies have mapped the disease gene to a 2 cM interval on Xp22.2 between DXS43 and DXS999. We report additional linkage data resulting from the analysis of eleven independent NHS families. A maximum lod score of 9.94 (theta=0.00) was obtained at the RS1 locus and a recombination with locus DXS1195 on the telomeric side was observed in two families, thus refining the location of the gene to an interval of around 1 Mb on Xp22.13. Direct sequencing or SSCP analysis of the coding exons of five genes (SCML1, SCML2, STK9, RS1 and PPEF1), considered as candidate genes on the basis of their location in the critical interval, failed to detect any mutation in 12 unrelated NHS patients, thus making it highly unlikely that these genes are implicated in NHS.
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PMID:Refinement of the NHS locus on chromosome Xp22.13 and analysis of five candidate genes. 1217 28

Nance-Horan syndrome (NHS) is an X-linked disorder characterized by congenital cataracts, dental anomalies, dysmorphic features, and, in some cases, mental retardation. NHS has been mapped to a 1.3-Mb interval on Xp22.13. We have confirmed the same localization in the original, extended Australian family with NHS and have identified protein-truncating mutations in a novel gene, which we have called "NHS," in five families. The NHS gene encompasses approximately 650 kb of genomic DNA, coding for a 1,630-amino acid putative nuclear protein. NHS orthologs were found in other vertebrates, but no sequence similarity to known genes was identified. The murine developmental expression profile of the NHS gene was studied using in situ hybridization and a mouse line containing a lacZ reporter-gene insertion in the Nhs locus. We found a complex pattern of temporally and spatially regulated expression, which, together with the pleiotropic features of NHS, suggests that this gene has key functions in the regulation of eye, tooth, brain, and craniofacial development.
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PMID:Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation. 1456 67

This paper gives the results of a needs assessment of a group of learning-disabled forensic patients from two Strategic Health Authority areas in the north of England. The patients were found to be a heterogeneous group with wide-ranging psychiatric needs. The majority were cared for outside their geographical area of origin, either in specialist NHS facilities or the independent sector. Those with an additional diagnosis of mental illness were most likely to be detained in NHS facilities within the region: a diagnosis of personality disorder was associated with placement in either a high secure setting or the independent sector. Individuals with a clinical diagnosis of mental retardation were most likely to be detained in services provided by specialist learning disability/mental health trusts out of area. There was a small group of females who were all placed outside the region. Offending behaviour was most likely to consist of violence against the person, sexual offences and arson. The majority assessed were felt to have long term needs. The study raised important implications for future provision of forensic services in the area, particularly the need to offer services with treatment programmes tailored to the needs of the population under review.
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PMID:Needs assessment in forensic learning disability. 1589 41

Nance-Horan syndrome (NHS) is an X-linked disorder characterized by congenital cataracts, dental anomalies, dysmorphic features and mental retardation. A recent report suggests that the novel gene NHS1 is involved in this disorder due to the presence of point mutations in NHS patients. A possible mouse model for NHS, Xcat, was mapped to a 2.11 Mb interval on the X-chromosome. Sequence and FISH analysis of the X-chromosome region containing the Xcat mutation reveal a large insertion between exons 1 and 2 of the mouse Nhs1 gene. The insertion inhibits the expression of the Nhs1 isoform containing exon 1 and results in exclusive expression of the alternative isoform containing exon 1A. Quantitative RT-PCR of Xcat cDNA shows reduced levels of Nhs1 transcripts. The Nhs1 protein is strongly expressed within the cytoplasm of elongating lens fiber cells from wild-type neonate lens, but is significantly reduced within the Xcat lens. Transient transfection studies of CHO cells with Nhs1-GFP fusion proteins were done to determine whether the amino acids encoded by exon 1 were critical for protein localization. We found the presence of Nhs1 exon 1 critical for localization of the fusion protein to the cytoplasm, whereas fusion proteins lacking Nhs1 exon 1 are predominantly nuclear. These results indicate that the first exon of Nhs1 contains crucial information required for the proper expression and localization of Nhs1 protein. Inhibition of expression of the exon 1 containing isoform results in the abnormal phenotype of Xcat.
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PMID:Xcat, a novel mouse model for Nance-Horan syndrome inhibits expression of the cytoplasmic-targeted Nhs1 isoform. 1635 5

We describe a male patient with a deletion at Xp22, detected by high resolution X-array CGH. The clinical phenotype present in this infant boy, consists of severe encephalopathy, congenital cataracts and tetralogy of Fallot and can be attributed to the deletion of the genes within the interval. Among these deleted genes are the gene for Nance-Horan syndrome and the cyclin-dependent kinase-like 5 gene (CDKL5), responsible for the early seizure variant of Rett syndrome. This is the first description of a male patient with a deletion of these genes, showing the involvement of CDKL5 in severe epileptic encephalopathy in males. Moreover it illustrates the added value of high resolution array-CGH in molecular diagnosis of mental retardation-multiple congenital anomaly cases.
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PMID:Encephalopathy and bilateral cataract in a boy with an interstitial deletion of Xp22 comprising the CDKL5 and NHS genes. 1725 98

Nance-Horan syndrome (NHS) is an X-linked developmental disorder characterized by congenital cataract, dental anomalies, facial dysmorphism and, in some cases, mental retardation. Protein truncation mutations in a novel gene (NHS) have been identified in patients with this syndrome. We previously mapped X-linked congenital cataract (CXN) in one family to an interval on chromosome Xp22.13 which encompasses the NHS locus; however, no mutations were identified in the NHS gene. In this study, we show that NHS and X-linked cataract are allelic diseases. Two CXN families, which were negative for mutations in the NHS gene, were further analysed using array comparative genomic hybridization. CXN was found to be caused by novel copy number variations: a complex duplication-triplication re-arrangement and an intragenic deletion, predicted to result in altered transcriptional regulation of the NHS gene. Furthermore, we also describe the clinical and molecular analysis of seven families diagnosed with NHS, identifying four novel protein truncation mutations and a novel large deletion encompassing the majority of the NHS gene, all leading to no functional protein. We therefore show that different mechanisms, aberrant transcription of the NHS gene or no functional NHS protein, lead to different diseases. Our data highlight the importance of copy number variation and non-recurrent re-arrangements leading to different severity of disease and describe the potential mechanisms involved.
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PMID:X-linked cataract and Nance-Horan syndrome are allelic disorders. 1941 85

Mutations in the NHS (Nance-Horan Syndrome) gene lead to severe congenital cataracts, dental defects and sometimes mental retardation. NHS encodes two protein isoforms, NHS-A and -1A that display cell-type dependent differential expression and localization. Here we demonstrate that of these two isoforms, the NHS-A isoform associates with the cell membrane in the presence of intercellular contacts and it immunoprecipitates with the tight junction protein ZO-1 in MDCK (Madin Darby Canine Kidney) epithelial cells and in neonatal rat lens. The NHS-1A isoform however is a cytoplasmic protein. Both Nhs isoforms are expressed during mouse development. Immunolabelling of developing mouse with the anti-NHS antibody that detects both isoforms revealed the protein in the developing head including the eye and brain. It was primarily expressed in epithelium including neural epithelium and certain vascular endothelium but only weakly expressed in mesenchymal cells. In the epithelium and vascular endothelium the protein associated with the cell membrane and co-localized with ZO-1, which indirectly indicates expression of the Nhs-A isoform in these structures. Membrane localization of the protein in the lens vesicle similarly supports Nhs-A expression. In conclusion, the NHS-A isoform of NHS is a novel interactor of ZO-1 and may have a role at tight junctions. This isoform is important in mammalian development especially of the organs in the head.
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PMID:NHS-A isoform of the NHS gene is a novel interactor of ZO-1. 1944 4

Nance-Horan syndrome (NHS) is an X-linked developmental disorder, characterized by bilateral congenital cataracts, dental anomalies, facial dysmorphism and mental retardation. Null mutations in a novel gene, NHS, cause the syndrome. The NHS gene appears to have multiple isoforms as a result of alternative transcription, but a cellular function for the NHS protein has yet to be defined. We describe NHS as a founder member of a new protein family (NHS, NHSL1 and NHSL2). Here, we demonstrate that NHS is a novel regulator of actin remodelling and cell morphology. NHS localizes to sites of cell-cell contact, the leading edge of lamellipodia and focal adhesions. The N-terminus of isoforms NHS-A and NHS-1A, implicated in the pathogenesis of NHS, have a functional WAVE homology domain that interacts with the Abi protein family, haematopoietic stem/progenitor cell protein 300 (HSPC300), Nap1 and Sra1. NHS knockdown resulted in the disruption of the actin cytoskeleton. We show that NHS controls cell morphology by maintaining the integrity of the circumferential actin ring and controlling lamellipod formation. NHS knockdown led to a striking increase in cell spreading. Conversely, ectopic overexpression of NHS inhibited lamellipod formation. Remodelling of the actin cytoskeleton and localized actin polymerization into branched actin filaments at the plasma membrane are essential for mediating changes in cell shape, migration and cell contact. Our data identify NHS as a new regulator of actin remodelling. We suggest that NHS orchestrates actin regulatory protein function in response to signalling events during development.
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PMID:The Nance-Horan syndrome protein encodes a functional WAVE homology domain (WHD) and is important for co-ordinating actin remodelling and maintaining cell morphology. 2033

Development and implementation of high-density DNA arrays demonstrated the important role of copy number changes on the X chromosome in the etiology of developmental delay and mental retardation (MR). We describe two unrelated patients with developmental delay due to similar interstitial duplications at Xp21-p22. The first patient is a 6-month-old male with multiple affected family members including many females. The second patient is a 5-year-old adopted female. In both patients, chromosome analysis and array comparative genomic hybridization (aCGH) showed duplications of overlapping regions at Xp21-p22. The duplicated segments contain numerous genes associated with MR, including AP1S2, NHS, CDKL5, RPS6KA3, SMS, and ARX. Except for developmental delay, there is little phenotypic overlap between the male and the female patient. Additionally, the female patient and affected female relatives of the male patient have variable severities of cognitive impairment, likely due to different X-inactivation patterns and effects of other, nonduplicated genes important for normal development. These cases illustrate that increased gene dosage of X-linked MR genes lead to cognitive impairment. Precise delineation of chromosome rearrangements by aCGH and identification of genes within duplicated segments helped in establishing genotype-phenotype correlations for each of our patients, in comparing them to each other, as well as with previously reported cases of Xp21-p22 duplications. However, we show that even with detailed molecular characterization, phenotype prediction remains challenging in patients with structural abnormalities of the X chromosome.
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PMID:Clinical and molecular characterization of overlapping interstitial Xp21-p22 duplications in two unrelated individuals. 2035


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