Spinocerebellar Ataxia, X-Linked 3

For a discussion of genetic heterogeneity of X-linked spinocerebellar ataxia (SCAX), see SCAX1 (302500).

Clinical Features

Schmidley et al. (1987) described an X-linked disorder of the central nervous system characterized by onset in infancy of hypotonia, ataxia, sensorineural deafness, developmental delay, esotropia, and optic atrophy, and by a progressive course leading to death in childhood. Histopathologically, a neuron loss and gliosis of the dentate nucleus and inferior olive were conspicuous; involvement of the cerebellar cortex was less prominent. In the proband, the red nucleus, dorsal motor nucleus of the vagus, and central auditory pathways were severely affected. The mother of the proband, aged 33 years, had self-limiting episodes of ataxia as well as cerebellar atrophy for which no other cause was apparent. The pedigree contained at least 6 affected males in 5 different sibships connected through carrier females in 3 successive generations. No report of a precisely similar disorder was discovered.

See also Arts syndrome (301835), which has similar features.