Adult-onset rapidly worsening progressive myoclonic epilepsy caused by a novel variant in DHDDS.

Progressive myoclonic epilepsy (PME) is a heterogeneous neurogenetic disorder manifesting as progressive myoclonus, seizure, and ataxia. We report a case of PME caused by a novel DHDDS variant. Additionally, by reviewing the literature on DHDDS mutations, we compared the phenotype of our patient with previously reported phenotypes. We identified DHDDS (c.638G>A, p. Ser213Asn) as a likely pathogenic variant. The literature review revealed 15 PME patients with DHDDS mutations from 13 unrelated families. According to previous studies, late-onset patients tend to have a slow-progressive disease course. Although his myoclonus and ataxia were adult onset, our patient experienced rapid disease aggravation.