DHDDS Mutation: A Rare Cause of Refractory Epilepsy and Hyperkinetic Movement Disorder

Developmental and epileptic encephalopathies are rare neurodevelopmental disorders characterized by early onset intractable seizures and frequent epileptiform activity on electroencephalogram associated with developmental delay or regression. The advent of next-generation sequencing has paved the way for discovering new genes responsible for these catastrophic epilepsy syndromes. Hyperkinetic movements have been described in some of these epileptic encephalopathies, such as mutations in ARX, GNAO1, CDKL5 and FOXG1 genes. We report a young female who presented with refractory epilepsy and hyperkinetic movement disorder comprising myoclonus, chorea and ataxia and was found to have a mutation in the DHDDS gene. A 25-year-old Sikh female born out of nonconsanguineous marriage presented with a history of generalized tonic-clonic