X-linked congenital ataxia: A new locus maps to Xq25-q27.1

We report clinical and molecular studies on a large American family of Norwegian descent with X-linked nonprogressive congenital ataxia (XCA) in six affected males over three generations. Neuroimaging showed global cerebellar hypoplasia without evidence of supratentorial anomalies. Linkage analysis resulted in a maximum LOD score Z=3.44 for marker DXS1192 at θ=0.0 with flanking markers DXS1047 and DXS1227 defining a region of 12 cM in Xq25-q27.1. The clinical and neuroradiological findings in the present family are very similar to those described in two reported X-linked families [Illarioshkin et al., 1996; Bertini et al., 2000]; however, the newly identified locus does not overlap with the one defined previously, indicating that there are at least two genes responsible for this rare form of X-linked congenital cerebellar ataxia with normal intelligence.