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)

A locus for X-linked hydrocephalus (HSAS), which is characterized by mental retardation and enlarged brain ventricles, maps to the same subchromosomal region (Xq28) as the gene for neural cell adhesion molecule L1. We have found novel L1 mRNA species in cells from affected members of a HSAS family containing deletions and insertions produced by the utilization of alternative 3' splice sites. A point mutation at a potential branch point signal in an intron segregates with the disease and is likely to be responsible for the abnormal RNA processing. These results suggest that HSAS is a disorder of neuronal cell migration due to disruption of L1 protein function.
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PMID:Aberrant splicing of neural cell adhesion molecule L1 mRNA in a family with X-linked hydrocephalus. 130 58

X-linked hydrocephalus-stenosis of the aqueduct of Sylvius sequence (H-SAS, MIM number 30007) is a rare genetic disorder characterized by hydrocephalus, macrocephaly, adducted thumbs, spasticity, agenesis of corpus callosum and mental retardation. We confirm here the localisation of the mutant gene on Xq (Xq 2.8) by linkage analysis in a 5-generation pedigree (maximum lod score of Z = 4.57 at theta = 0.04 with probe St14 at locus DXS52) and emphasise the phenotypic variability of the disease. Ventricular dilatation in affected males was either severe and diagnosed antenatally or moderate and consistent with a long survival with little or no macrocephaly. Since other X-linked syndromes of mental retardation with spasticity and flexion deformities of the thumbs have previously been shown to map to the Xq 2.8 region as well (e.g. MASA syndrome and spastic paraplegia), the present results raise the question of whether H-SAS syndrome, MASA syndrome and spastic paraplegia with mental retardation might represent different phenotypic expression of various mutations at the same locus.
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PMID:X-linked hydrocephalus: clinical heterogeneity at a single gene locus. 139 13

X-linked hydrocephalus (HSAS) is the most frequent genetic form of hydrocephalus. Clinical symptoms of HSAS include hydrocephalus, mental retardation, clasped thumbs, and spastic paraparesis. Recently we have assigned the HSAS gene to Xq28 by linkage analysis. In the present study we used a panel of 18 Xq27-q28 marker loci to further localize the HSAS gene in 13 HSAS families of different ethnic origins. Among the Xq27-q28 marker loci used, DXS52, DXS15, and F8C gave the highest combined lod scores, of 14.64, 6.53 and 6.33, respectively, at recombination fractions of .04, 0, and .05, respectively. Multipoint linkage analysis localizes the HSAS gene in the telomeric part of the Xq28 region, with a maximal lod score of 20.91 at 0.5 cM distal to DXS52. Several recombinations between the HSAS gene and the Xq28 markers DXS455, DXS304, DXS305, and DXS52 confirm that the HSAS locus is distal to DXS52. One crossover between HSAS and F8C suggests that HSAS gene to be proximal to F8C. Therefore, data from multipoint linkage analysis and the localization of key crossovers indicate that the HSAS gene is most likely located between DXS52 and F8C. This high-resolution genetic mapping places the HSAS locus within a region of less than 2 Mb in length, which is now amenable to positional cloning.
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PMID:Further localization of X-linked hydrocephalus in the chromosomal region Xq28. 164 32

X-linked recessive hydrocephalus (HSAS) occurs at a frequency of approximately 1 per 30,000 male births and consists of hydrocephalus, stenosis of the aqueduct of Sylvius, mental retardation, spastic paraparesis, and clasped thumbs. Prenatal diagnosis of affected males by ultrasonographic detection of hydrocephalus is unreliable because hydrocephalus may be absent antenatally. Furthermore, carrier detection in females is not possible because they are asymptomatic. Using four families segregating HSAS, we performed linkage analysis with a panel of X-linked probes that detect restriction fragment length polymorphisms. We report here that HSAS, in all tested families, is closely linked to marker loci mapping in Xq28 (DXS52, lod = 6.52 at theta of 0.03; F8, lod = 4.32 at theta of 0.00; DXS15, lod = 3.40 at theta of 0.00). These data assign HSAS to the gene-dense chromosomal band Xq28 and allow for both prenatal diagnosis and carrier detection by linkage analysis.
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PMID:Assignment of X-linked hydrocephalus to Xq28 by linkage analysis. 197 56

We report on a family with X-linked hydrocephalus: progressive increase in head circumference (OFC) led to the diagnosis in 3 patients; however, in 5 with normal OFC, the initial diagnosis had been "nonspecific" mental retardation, until identification of relatedness between 3 macrocephalic boys suggested segregation of a major Mendelian gene. Moderate to severe hydrocephaly was present in all macrocephalic patients and in 3 of the 5 with normal OFC, but CT-scan of the brain did not show aqueductal stenosis in any of them. We stress the importance of a brain CT-scan in every male with "nonspecific" mental retardation, especially in cases with X-linked inheritance, because confirmation of X-linkage has important genetic counseling consequences.
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PMID:X-linked hydrocephalus. 342 2

X-linked hydrocephalus (HSAS) (MIM *307000), MASA syndrome (MIM *303350), and complicated spastic paraplegia (SPG1) (MIM *312900) are closely related. Soon after delineation, SPG1 was incorporated into the spectrum of MASA syndrome. HSAS and MASA syndrome show great clinical overlap; DNA linkage analysis places the loci at Xq28. In an increasing number of families with MASA syndrome or HSAS, mutations in L1CAM, a gene located at Xq28, have been reported. In order to further delineate the clinical spectrum, we studied 6 families with male patients presenting with MASA syndrome, HSAS, or a mixed phenotype. We summarized data from previous reports and compared them with our data. Clinical variability appears to be great, even within families. Problems in genetic counseling and prenatal diagnosis, the possible overlap with X-linked corpus callosum agenesis and FG syndrome, and the different forms of X-linked complicated spastic paraplegia are discussed. Since adducted thumbs and spastic paraplegia are found in 90% of the patients, the condition may be present in males with nonspecific mental retardation. We propose to abandon the designation MASA syndrome and use the term HSAS/MASA spectrum, incorporating SPG1.
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PMID:Spectrum of X-linked hydrocephalus (HSAS), MASA syndrome, and complicated spastic paraplegia (SPG1): Clinical review with six additional families. 764 88

Neural cell adhesion proteins play important roles in neural development and are involved in various neurological diseases. P0, a major protein in mammalian peripheral myelin, mediates not only homophilic cell adhesion but also neurite outgrowth. The P0 glycopeptide inhibits the cell adhesion, but not the neurite outgrowth. Several point mutations of the P0 gene in human chromosome 1q22-23 were found in Charcot-Marie-Tooth (CMT) disease type 1B and Dejerine-Sottas (DS) disease. PASII/PMP22 and connexin 32 were also reported as target proteins of similar hereditary neuropathies. L1 is a large multifunctional protein involved in cell adhesion, neurite outgrowth, fasciculation, and neuronal cell migration. A short isoform of L1 localizes in non-neuronal cells in contrast to the complete L1 exclusively expressed in neurons. Recently various L1 mutations have been reported in X-linked hydrocephalus, MASA syndrome with mental retardation and spastic paraplegia type 1. Further studies on the mutations and disease phenotypes are important and interesting.
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PMID:Neural cell adhesion proteins and neurological diseases. 770 5

The neural cell-adhesion molecule L1 is involved in intercellular recognition and neuronal migration in the CNS. Recently, we have shown that mutations in the gene encoding L1 are responsible for three related disorders; X-linked hydrocephalus, MASA (mental retardation, aphasia, shuffling gait, and adducted thumbs) syndrome, and spastic paraplegia type I (SPG1). These three disorders represent a clinical spectrum that varies not only between families but sometimes also within families. To date, 14 independent L1 mutations have been reported and shown to be disease causing. Here we report nine novel L1 mutations in X-linked hydrocephalus and MASA-syndrome families, including the first examples of mutations affecting the fibronectin type III domains of the molecule. They are discussed in relation both to phenotypes and to the insights that they provide into L1 function.
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PMID:New domains of neural cell-adhesion molecule L1 implicated in X-linked hydrocephalus and MASA syndrome. 776 52

We report on a woman with four successive pregnancies affected with X-linked hydrocephalus (XLH). The first child had prenatal craniocentesis and died in utero. The second child had a postnatal shunting operation, but suffers from severe growth and mental retardation at 5 years of age. In the third pregnancy, prenatal ultrasound detected hydrocephalus at the 16th and 20th weeks of gestation and the pregnancy was terminated. In the fourth pregnancy, ultrasound scanning at the 17th and 20th weeks of gestation revealed no remarkable findings, but hydrocephalus was detected at the 24th week. Autopsy confirmed the prenatal diagnosis. DNA polymorphism analysis of the Bc1I site of exons 17-18 of factor VIII gene of the woman and her last two fetuses seemed to be compatible with a linkage between the XLH locus and factor VIII gene. Although XLH has a variable presentation of ventriculomegaly, ultrasound scanning is still a useful tool for prenatal diagnosis at present. Earlier and more accurate prenatal diagnosis will be feasible with molecular analysis of the XLH locus or its flanking regions.
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PMID:Prenatal diagnosis of X-linked hydrocephalus in a Chinese family with four successive affected pregnancies. 791 Mar 98

MASA syndrome is a recessive X-linked disorder characterized by mental retardation, adducted thumbs, shuffling gait, aphasia and, in some cases, hydrocephalus. Since it has been shown that X-linked hydrocephalus can be caused by mutations in L1CAM, a neuronal cell adhesion molecule, we performed an L1CAM mutation analysis in eight unrelated patients with MASA syndrome. Three different L1CAM mutations were identified: a deletion removing part of the open reading frame and two point mutations resulting in amino acid substitutions. L1CAM, therefore, harbours mutations leading to either MASA syndrome or HSAS, and might be frequently implicated in X-linked mental retardation with or without hydrocephalus.
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PMID:MASA syndrome is due to mutations in the neural cell adhesion gene L1CAM. 792 Jun 60


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