It is of interest that STX1B- and STXBP1-related DEEs both feature ataxia and other movement disorders.28 However, in the vast majority of STXBP1-related epilepsy syndromes, moderate to severe developmental delay is present27, –, 29—milder phenotypes, as in our cohort, are not observed. The gene discussed is STX1B; the disease is cerebellar ataxia.