A Novel Mutation in KMT2B Gene Causing Childhood -onset Generalized Dystonia with Expanded Phenotype from India

Mutations in KMT2B (lysine-specific methyltransferase 2B) gene, which is primarily involved in methylation of Histone3lys4 (H3K4), has been recently described to cause early -onset generalized progressive dystonia (DYT28) by two independent researchers. Unlike other primary dystonias, mutations in KMT2B gene is associated with additional features like dysmorphism (elongated face, bulbous nose), microcephaly: short stature, and multisystemic involvement. Herein, we describe a 13 -year-old boy with early-onset, generalized, progressive complex severe dystonia, along with mild intellectual disability, dysmorphism, and dermatological manifestations associated with a novel missense variation in KMT2Bgene and also expand the phenotypic spectrum of the same.