Differentiating congenital myasthenic syndromes from autoimmune myasthenia gravis
| Suggestive of autoimmune myasthenia gravis | Suggestive of congenital myasthenic syndromes |
|---|---|
| Precipitous onset from normal although mild previous abnormalities may have been missed | Onset at birth or infancy |
| Marked asymmetry of ptosis and fluctuation in ophthalmoplegia with diplopia | Ankle dorsiflexion weakness common in congenital myasthenic syndromes but almost never a feature of myasthenia gravis |
| Response to immunotherapies | Ophthalmoplegia not responsive to treatment |
| Spontaneous resolution especially in children | Family history or consanguinity in parents |
| Dysmorphic features due to early in utero weakness |