A family in which a gene (MRX2) is segregating for an X-linked syndrome of mental retardation, short stature, microcephaly, brachycephaly, spastic diplegia, small testes and possible intra-uterine growth retardation is described. There are 7 clearly affected males and one possibly affected infant in the family. The obligate carriers are normal. Linkage studies show a suggestion of linkage to loci near the centromere. The maximum lod score was 2.10 at θ=0.11 for DXYS1, assuming the possibly affected male carried the MRX2 gene. There were lower lod scores suggestive of linkage with DXS7 (θ=0.14; z=1.29) and DXS94 (θ=0.11; z=1.22).