The Congenital Myasthenic Syndromes (CMS) are a group of rare genetic disorders affecting neuromuscular transmission and often presents within first year of life. A high index of suspicion is usually required as clinical manifestations can be variable and non specific. RAPSN mutations are likely to be one of the common causes for CMS in patients of Indo-European ethnic origin. Clinical phenotype includes arthrogryposis, respiratory crises, transient torticollis at birth, facial deformities and weakness. Chronic stridor as an early manifestation of CMS has not been described before.