Mental Retardation, X-Linked 84

Clinical Features

Zhang et al. (2004) reported a Chinese family in which 3 males in 3 generations had nonspecific X-linked mental retardation. The obligate carrier females were not affected.

Mapping

By 2-point linkage analysis, Zhang et al. (2004) demonstrated linkage of nonspecific mental retardation in a Chinese family to several markers located at Xq22.2, with a maximum lod score of 2.41 at theta = 0.0 for 2 adjacent markers (DXS1191 and DXS1230). Recombination events were observed with flanking markers DXS8080 and DXS456, located at Xp11.3 and Xq22.3, respectively, and a region of approximately 22.3 cM was defined. The localized region observed in this family overlapped with 29 other MRX loci previously reported in Xp11.3-q22.3.