Age at onset was predominantly in childhood in patients with dystroglycanopathies, LGMD-R10-TTN-related and LMNA-related muscular dystrophy and in childhood or adolescence in those with LGMD-R1-calpain3-related, dysferlinopathy, LGMD-R7-telethonin-related and LGMD-R18-TRAPPC11-related. The gene discussed is TTN; the disease is limb-girdle muscular dystrophy.