Congenital myasthenic syndromes and transient myasthenia gravis.

Hypotonia in the neonatal period and early infancy is a common clinical finding. It can be caused by various heterogeneous disorders of different origin which might lead to diagnostic difficulties. Disorders of the neuromuscular junction, such as congenital myasthenic syndromes and neonatal transient myasthenia gravis are among the aetiologies. We report on a case of congenital myasthenia caused by mutation in the long cytoplasmic loop of the epsilon subunit of the acetylcholine receptor and a neonate of a myasthenic mother diagnosed with transient myasthenia gravis.