Congenital Myasthenic Syndrome Panel

Congenital myasthenic syndromes (CMS) are heterogeneous inherited disorders of neuromuscular transmission characterized by fatigable weakness of the skeletal muscle with onset at or shortly after birth or in early childhood. In CMS, the safety margin of neuromuscular transmission is compromised, and clinical evaluation should involve detailed electromyographic studies to demonstrate a defect in neuromuscular transmission. Severity and progression can vary. Major findings in the neonatal onset subtype include feeding difficulties, poor suck and cry, choking spells, ptosis, facial, bulbar and generalized weakness. Later childhood onset subtypes show abnormal muscle fatigability, motor milestones may be delayed, ptosis, and fixed or fluctuating extraocular muscle weakness. Most CMS are inherited in an autosomal recessive pattern. This panel includes sequence and deletion/duplication analysis of all the listed genes.