Mental Retardation, X-Linked 77

Clinical Features

Sismani et al. (2003) reported a Greek family with apparently nonsyndromic X-linked mental retardation. The affected males had moderate to severe mental retardation, severe speech problems, and aggressive behavior.

Mapping

Sismani et al. (2003) performed linkage analysis on a Greek family with apparently nonsyndromic X-linked mental retardation. Two-point linkage analysis with 26 polymorphic markers spanning the entire X chromosome allowed assignment of the causative gene to a 27-Mb interval in Xq12-q21.3.

Molecular Genetics

Exclusion Studies

In affected members of a family segregating X-linked mental retardation, Sismani et al. (2003) performed DNA analysis of 3 known or candidate MRX genes from the Xq12-q21 region, OPHN1 (300127), ATRX (300032), and RSK4 (300303), and found no mutations.