SPINOCEREBELLAR ATAXIA 32; SCA32

Cytogenetic location: 7q32-q33 Genomic coordinates (GRCh38): 7:130,800,000-138,500,000

▼ Description
Spinocerebellar ataxia-32 (SCA32) is an autosomal dominant neurologic disorder characterized by ataxia, variable mental impairment, and azoospermia in males (summary by Jiang et al., 2010).

For a general discussion of autosomal dominant spinocerebellar ataxia, see SCA1 (164400).

▼ Clinical Features
Jiang et al. (2010) reported a Chinese family with an autosomal dominant form of spinocerebellar ataxia. There was a broad range of age at onset, particularly among females. Those with onset of ataxia before age 40 years showed cognitive impairment, and brain MRI showed cerebellar atrophy. All affected males were infertile and had azoospermia with testicular atrophy. Testicular biopsy from 1 male showed complete absence of germ cells and progenitors.

▼ Mapping
By genomewide linkage analysis of a Chinese family with autosomal dominant SCA and azoospermia, Jiang et al. (2010) found linkage to a locus, termed SCA32, on chromosome 7q32-q33 between rs3847110 and rs2241728. The critical region spanned 0.989 cM (989 kb).