Spinal Muscular Atrophy, Segmental

Description

Segmental spinal muscular atrophy is a form of anterior horn cell disease that affects predominantly the hand muscles (Kamholz et al., 1988). The disease is usually sporadic and nonprogressive.

Cytogenetics

Kamholz et al. (1988) found typical features of segmental spinal muscular atrophy in a woman who also had a deletion of part of the long arm of chromosome 18; the q21.3-qter segment was missing. She had normal intelligence, although she had had some learning difficulties, and did not have the dysmorphic features usually associated with the 18q- syndrome. By molecular methods, Kamholz et al. (1988) demonstrated that the deletion included the myelin basic protein gene (159430) but did not include the transthyretin gene (176300).