CDKL5 deficiency disorder (CDD) and SLC6A1 epileptic encephalopathy are rare neurogenetic epilepsy conditions whose patterns of clinical care remain poorly characterized. Here we describe medication trends for patients with CDD and SLC6A1. 

Within 1 year of diagnosis, 64% (21/33) of a combined group of CDD and SLC6A1 patients were prescribed ≥ 1 seizure medication, 36% (12/33) were prescribed ≥ 2, and 30% (10/33) ≥ 3 (mean: 2.7, median: 2). 

Levetiracetam was prescribed to the greatest number of both CDD and SLC6A1 patients (86% and 61%, respectively). 60% of CDD patients were prescribed GABA analogs, which were not prescribed to any SLC6A1 patients (p = 2.02e-6). Significantly more CDD patients were prescribed topiramate than SLC6A1 patients (69%, 14%,  p = 5.04e-5). More than half of CDD patients were prescribed a barbiturate anticonvulsant compared to < 3 SLC6A1 patients (p = .00012). Over 20% of SLC6A1 patients were prescribed CNS stimulants, which were not prescribed to any CDD patients (p = .0055). 

65% of patients stopped ≥ 1 medication due to inefficacy (CDD: 24/35 (69%); SLC6A1: 17/28 (61%); mean: 2.7 medications). The medications most commonly stopped due to inefficacy were levetiracetam for CDD (11/30, 37%) and levetiracetam and ethosuximide for SLC6A1 (7/17, 41%).

Future research could further examine medication patterns, including genetic or phenotypic correlates of medication efficacy. Such studies may help improve seizure management for patients with these rare epilepsies.