Dystonia and Contractures are Potential Early Signs of -Related Epileptic Encephalopathy.

Epileptic encephalopathy related to has been described as a severe neurodevelopmental disorder presenting with early-onset refractory seizures, hypotonia, macrocephaly, hyperkinetic movements, and contractures and is associated with an autosomal dominant inheritance pattern. Most pathogenic variants described to date are missense variants with a gain of function effect, and the role of haploinsufficiency has yet to be clarified. We describe 2 cases of encephalopathy. Notable findings include congenital contractures and movement disorders predating onset of epilepsy, particularly dystonia. We further compared the key phenotypic features depending on variant location. In conclusion, the appearance of congenital contractures, areflexia, and movement disorders before the onset of epilepsy may provide key guidance in the diagnosis of epileptic encephalopathy. A genotype-phenotype correlation was found between the presence of movement disorders and severe intellectual disability and the location of the variant in the gene.