Clinical, pathological, and genetic features of limb‐girdle muscular dystrophy type 2A with new calpain 3 gene mutations in seven patients from three Japanese families

We report on the clinical, pathological, and genetic features of 7 patients with limb-girdle muscular dystrophy type 2A (LGMD2A) from three Japanese families. The mean age of onset was 9.7 ± 3.1 years (mean ± SD), and loss of ambulance occurred at 38.5 ± 2.1 years. Muscle atrophy was predominant in the pelvic and shoulder girdles, and proximal limb muscles. Muscle pathology revealed dystrophic changes. In two families, an identical G to C mutation at position 1080 the in calpain 3 gene was identified, and a frameshift mutation (1796insA) was found in the third family. The former mutation results in a W360R substitution in the proteolytic site of calpain 3, and the latter in a deletion of the Ca2+-binding domain. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1493–1501, 1998