A rare case of congenital fibre type disproportion causing delayed motor milestones.

A two year and four month old boy who was the second child of a non-consanguineous marriage was investigated for delayed motor mile stones and dysarthria. The patient had an uneventful antenatal history. He started walking at the age of two years. There was no progressive proximal muscle weakness. Examination showed long facies and a squint. Muscle tone in both upper and lower limbs was mildly reduced. Creatine phosphokinase levels were normal, 65U/L (24-195U/L). The nerve conduction study excluded spinal muscular atrophy.