title: X-linked nonspecific mental retardation (MRX16) mapping to distal Xq28: linkage study and neuropsychological data in a large family.
abstract: A genetic linkage study was performed on a large four-generation family with variable nonspecific X-linked mental retardation (MRX16), speech abnormalities, and retardation of all milestones. Significant linkage was found in the Xq28 region with loci DXS52, DXS15, BGN, and DXS1108 with maximum LOD scores of 4.86, 4.01, 4.83, and 5.43, respectively, at theta = 0.00. Recombination was observed at the locus DXS1113, thus mapping the gene in an 8-Mb interval between this marker and the Xq telomere. Linkage intervals of three other MRX families overlap with this interval in Xq28 where the RABGDIA gene, mutated in the MRX41 and MRX48 families, is also located. In MRX3, MRX28, but also in MRX16, no alteration of RABGDIA has been found, thus suggesting the existence of at least two MRX genes in distal Xq28.
authors.affiliation: Laboratoire de Biochimie et Biologie Moléculaire and INSERM U316, CHU Bretonneau, Tours, France.
authors.forename: C
authors.initials: C
authors.lastname: Gendrot
authors.forename: N
authors.initials: N
authors.lastname: Ronce
authors.forename: M
authors.initials: M
authors.lastname: Raynaud
authors.forename: A D
authors.initials: AD
authors.lastname: Ayrault
authors.forename: J
authors.initials: J
authors.lastname: Dourlens
authors.forename: P
authors.initials: P
authors.lastname: Castelnau
authors.forename: J P
authors.initials: JP
authors.lastname: Muh
authors.forename: J
authors.initials: J
authors.lastname: Chelly
authors.forename: C
authors.initials: C
authors.lastname: Moraine
mesh_terms: D002874:Chromosome Mapping; D005190:Family; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008126:Lod Score; D008297:Male; D009483:Neuropsychological Tests; D010375:Pedigree; D010641:Phenotype; D017422:Sequence Analysis, DNA; D014960:X Chromosome