Mental Retardation, X-Linked 82

Clinical Features

Martinez et al. (2004) described a Basque family in which 5 males in 4 sibships in 2 generations had nonsyndromic mental retardation.

Mapping

In a Basque family with nonsyndromic mental retardation, Martinez et al. (2004) found linkage to Xq24-q25 with a maximum lod score of 2.4. Haplotype studies and multipoint linkage analysis suggested a localization of the MRX82 locus to an interval of 7.6 Mb defined by markers DXS6805 and DXS7346, in Xq24 and Xq25, respectively. The linked interval contained the gene encoding glutamate receptor-3 (GRIA3; 305915), but mutation analysis showed no pathologic changes.