Myotonia congenita (Becker's variant).

A 21 year old right handed male resident of Bihar presented with 4 years history of gradual onset progressive st i f fness in both thighs and calves which improves on continued activity along with hypertrophy of muscles of all the limbs and dimpling on hitting over thigh and hands. He also has history of inability to walk fast or run and delayed opening of left eye after forceful closure of both eyes for past 8 months.