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 KMT2B gene and also expand the phenotypic spectrum of the same.