KMT2B and Dystonia: KMT2B-related dystonia has been defined “complex” in that additional neurological and systemic features have been recognized in some of the mutation carriers, including psychomotor and language delay, minor dysmorphic traits and a characteristic facial appearance (bulbous nasal tips and elongated face), mild-to-moderate ID, short stature, skin abnormalities, and psychiatric disturbances [26••].