A new X linked mental retardation (XLMR) syndrome with short stature, small testes, muscle wasting, and tremor localises to Xq24-q25.
METHODS: A large family is described in which mental retardation segregates as an X linked trait. Six affected males in three generations were studied by linkage and clinical examination. RESULTS: Characteristic clinical features include short stature, prominent lower lip, small testes, muscle wasting of the lower legs, kyphosis, joint hyperextensibility, abnormal gait, tremor, and decreased fine motor coordination. Affected subjects also had impaired speech and decreased attention span. A carrier female was mildly affected. A similar disorder was not found on review of our XLMR Database of 124 syndromes. Linkage analysis of 37 markers resulted in a lod score of 2.80 at DXS1212 and 2.76 at DXS425. The limiting markers were DXS424 and DXS1047. Ten of 124 XLMR syndromes and eight of 58 MRX families overlap this region. CONCLUSIONS: In summary, this family appears to have a new XLMR syndrome localising to Xq24-q25.