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)

FG syndrome is an X-linked condition comprising mental retardation, congenital hypotonia, macrocephaly, distinctive facial changes, and constipation or anal malformations. In a linkage analysis, we mapped a major FG syndrome locus [FGS1] to Xq13, between loci DXS135 and DXS1066. The same data, however, clearly demonstrated genetic heterogeneity. Recently, we studied a French family in which an inversion [inv(X)(q12q28)] segregates with clinical symptoms of FG syndrome. This suggests that one of the breakpoints corresponds to a second FG syndrome locus [FGS2]. We report the results of fluorescence in situ hybridization analysis performed in this family using YACs and cosmids encompassing the Xq11q12 and Xq28 regions. Two YACs, one positive for the DXS1 locus at Xq11.2 and one positive for the color vision pigment genes and G6PD loci at Xq28, were found to cross the breakpoints, respectively. We postulate that a gene might be disrupted by one of the breakpoints.
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PMID:Mapping of X chromosome inversion breakpoints [inv(X)(q11q28)] associated with FG syndrome: a second FG locus [FGS2]? 1107 72

FG syndrome (OMIM 305450) is an X-linked condition comprising mental retardation, congenital hypotonia, constipation or anal malformations, and a distinctive appearance with disproportionately large head, tall and broad forehead, cowlicks and telecanthus. In a first linkage analysis carried out on 10 families, we demonstrated heterogeneity and assigned one gene [FGS1] to region Xq12-q21.31 [Briault et al., 1997: Am J Med Genet 73:87-90] corroborated by Graham et al. [1998: Am J Med Genet 80:145-156]. Heterogeneity was supported by the study of one family with apparent FG syndrome co-segregating with an inversion of X chromosome [inv(X)(q11q28)] ([FGS2], OMIM 300321) [Briault et al., 1999: Am J Med Genet 86:112-114 and Briault et al., 2000: Am J Med Genet 95:178-181]. We present the results of a new linkage analysis carried out on two families with FG syndrome. The two earlier known loci for FG syndrome, FGS1 and FGS2 (Xq11 or Xq28) were excluded by multipoint analysis of both families. Linkage was found, however, with locus DXS1060 suggesting that a third FG locus might be located at Xp22.3. In this region, two potential candidate genes, VCX-A and PRKX, were excluded by sequence analysis of the coding region in patients of the two reported FG families. The search for new candidate genes is in progress.
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PMID:FG syndrome: linkage analysis in two families supporting a new gene localization at Xp22.3 [FGS3]. 1223 12

FG syndrome (FGS, MIM 305450) is a rare X-linked recessive disorder comprising mental retardation and multiple malformations. Various families have been described to date, increasing our knowledge of the phenotype variability and making the clinical diagnosis complex, especially in sporadic patients. The first locus for FG syndrome (FGS1) was linked to chromosome region Xq12-q21.31, but other families have been excluded from this locus. The genetic heterogeneity of FG syndrome has been confirmed by analysis of an X chromosome inversion [inv(X)(q11q28)] in an affected boy and in his mentally retarded maternal uncle, suggesting that an additional locus for FG syndrome (FGS2, MIM 300321) is located at either Xq11 or Xq28. Recently, a third locus (FGS3) has been mapped to Xp22.3. We have identified and clinically characterized an Italian FG family, including 31 members with three affected males in two generations and two obligate carriers. We have excluded linkage to known FGS loci, whereas an extensive study of the whole X chromosome has yielded a maximum LOD score (Z(max)) of 2.66 (recombination fraction=0) for markers between DXS8113 and sWXD805. This new locus for FG syndrome corresponds to a region of approximately 4.6 Mb on the X chromosome.
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PMID:Genetic heterogeneity of FG syndrome: a fourth locus (FGS4) maps to Xp11.4-p11.3 in an Italian family. 1252 52

FG syndrome was originally described as a rare syndromic cause of X-linked mental retardation associated with congenital heart disease, anal atresia, inguinal hernia, cryptorchidism, and other anomalies. However, recent reports have highlighted the more common milder presentation which has for cardinal features developmental delay, particularly in speech, neonatal hypotonia, relative macrocephaly, dysmorphic facial features, severe constipation, and few if any congenital malformations. Thus far, five separate loci have been identified on the X chromosome but attempts at finding the responsible gene have not yet been successful. Given that one putative FG locus (FGS2) is situated at Xq28, which is the location of the Filamin A gene (FLNA), and that a Filamin A mutation was reported in a boy with facial dysmorphism and constipation, it was hypothesized that Filamin A mutations could be one cause of FG syndrome. Indeed, a previously unreported FLNA missense mutation (P1291L) was detected in our patient with FG syndrome, thus supporting this hypothesis and indicating that FG syndrome could now be added to the list of Filamin A-related disorders. Filamin A studies in other children with FG syndrome would help to confirm this association.
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PMID:Filamin A mutation is one cause of FG syndrome. 1763 75