The term Gastrocnemius Myalgia Syndrome (GMS) was first introduced by Christopoulos et al. (5) in 2003 and included myalgia confined to the gastrocnemius muscles as localized form of myositis, serum CPK levels within the normal range and a rapid response to corticosteroid therapy (10). The gene discussed is PIK3C2A; the disease is myositis disease.