Mental Retardation, X-Linked 73

Clinical Features

Martinez et al. (2001) reported a 4-generation family in which 5 males had mild to moderate nonspecific mental retardation. Brain CT scan performed in 1 patient was normal.

Inheritance

The pedigree pattern in the family with mental retardation reported by Martinez et al. (2001) was consistent with X-linked inheritance.

Mapping

By typing of markers throughout the X chromosome in a 4-generation family with nonsyndromic mental retardation, Martinez et al. (2001) mapped the phenotype locus to a 2-cM interval between markers DXS8019 and DXS365 on chromosome Xp22.2.

Molecular Genetics

Exclusion Studies

In a family with nonsyndromic mental retardation mapping to Xp22.2, Martinez et al. (2001) performed direct sequencing of the RSK2 gene (300075) but found no causal mutation. They concluded that another unidentified gene for X-linked mental retardation is located near RSK2.