Overview

Congenital myasthenic syndromes are rare hereditary (genetic) conditions resulting from a defect at the junction where your nerve stimulates muscle activity. That defect causes muscle weakness.

Congenital myasthenic syndromes may affect your nerve cells (presynaptic), your muscle cells (postsynaptic), or the space between your nerve and muscle cells (synaptic).

Congenital myasthenic syndromes care at Mayo Clinic