To determine the frequency of epilepsy and seizures in patients with familial dysautonomia (FD, hereditary sensory autonomic neuropathy III).

Patients with FD have frequent paroxysmal episodes concerning for seizure. The differential diagnosis of these episodes is ample and includes autonomic crisis, hypoxia, and hypotension. Our aim was to categorize the EEG results and the frequency of epileptiform activity in a large sample of patients with genetically confirmed FD.

Retrospective chart review of all cases with FD documented in the New York University FD Patient Registry, which includes virtually every patient diagnosed with FD. We used the search terms “EEG”, “epilepsy”, and “seizure.”

Out of 676 subjects documented in the NYU FD Patient Registry, we identified 399 adult and pediatric patients that had diagnostic tests (EEG, polysomnography) performed for possible seizure events between 1951 and 2018. Of these, 147 (36.8 %) patients had normal findings and 121 (30.3 %) had epileptiform EEG patterns. Non-epileptiform EEG findings including generalized or focal slowing or generalized or focal cerebral dysfunction, were present in 74 (18.5 %) patients. Forty patients (10%) had nonspecific results and 6 (1%) had beta activity possibly related to benzodiazepines.