This inherited (autosomal recessive) condition is characterized by a type 2 muscle fiber deficiency. Clinical signs are seen at <5 mo of age and include skeletal muscle atrophy, stunted growth, ataxia, and weakness. Signs are progressive until the animal reaches maturity, when they stabilize. Animals may have a normal life span. Diagnosis is by creatinuria, muscle biopsy, and electromyography. Histology reveals increased connective tissue around muscle fibers and staining deficiency of type II fibers. Myotonic discharges are seen with an electromyography. There is no effective treatment.

Last full review/revision March 2012 by Joseph Harari, MS, DVM, DACVS