'Juvenile' myasthenia gravis in early infancy.

A previously well infant developed severe muscle weakness and hypotonia at 6 months of age. This was reversed by anticholinesterase medication. However, she had subsequent further weakness and died at 10 months after an acute respiratory arrest. The clinical pattern was that of the 'juvenile' form of myasthenia gravis rather than the 'congenital' forms which have previously been described in early infancy.