Congenital and developmental myasthenia

This code describes a group of rare, inherited disorders affecting the neuromuscular junction, leading to muscle weakness and fatigue. These conditions are present at birth or manifest early in life due to genetic defects impacting neurotransmission.

Use this code for patients diagnosed with congenital myasthenic syndromes (CMS), which are distinct from autoimmune myasthenia gravis. Documentation should clearly indicate a genetic basis or early onset of myasthenic symptoms not attributable to an autoimmune process.

• Differentiate carefully from acquired autoimmune myasthenia gravis (G70.0-).
• Review genetic testing results or detailed family history for supporting documentation.
• Consider additional codes for specific genetic mutations or associated clinical manifestations if documented.