Primary skeletal muscle involvement in chorea-acanthocytosis

Chorea-acanthocytosis (ChAc) is a hereditary disease characterized by involuntary movements and amyotrophy with elevation of serum creatine kinase. Although skeletal muscle involvement in ChAc has been suggested, the mechanism remains unclear. To investigate chorein abnormalities of the skeletal muscles of ChAc patients with an apparently heterozygous VPS13A mutation compared with those of other hereditary choreic diseases, we performed histological and immunohistochemical studies of the skeletal muscles from 3 ChAc, 1 Huntington's disease (HD), 1 McLeod syndrome (MLS), and 1 normal control (NC) with 2 originally generated anti-chorein antibodies. Chorein immunoreactivities in HD, MLS, and NC were found linearly along the sarcolemma and appeared as speckles in the sarcoplasma, but those in ChAc were uneven and discontinuous along the sarcolemmas and increased in the sarcoplasma especially in type I fibers. This histological observation suggests chorein abnormalities of skeletal muscles might be associated with primary involvement of skeletal muscles in this disorder.