Stricter clinical criteria can increase the likelihood of confirming congenital myasthenic syndromes (CMS) diagnosis but may lose sensibility for specific genes.
Why this matters
CMS are a heterogeneous group of rare genetic diseases characterized by compromised neuromuscular transmission. CMS is suspected when there is ocular and cranial muscle weakness, pediatric onset, a negative myasthenia gravis autoantibody test, and supportive electrophysiological data.
However, CMS can resemble other neuromuscular diseases, particularly congenital and mitochondrial myopathies, which makes diagnosis difficult. Therefore, clinical, histological, and electrophysiological features of patients with CMS requires more precise mapping to improve diagnosis.