..and the Other Common Cause
A 22 year old is presented with Achilles tendon tightening from a young age and progressive proximal weakness over the past 4 years. Creatine kinase was markedly elevated at 5196 (<140) with electromyography showing myopathic features. Immunostaining of her muscle biopsy showed significantly reduced immunolabelling for Calpain-3 and undetectable Calpain-3 bands on immunoblotting. Compound heterozygous mutations in Calpain-3 gene were detected.