HSD10 disease, atypical type is a clinical subtype of HSD10 disease, a rare neurometabolic disorder. Manifestations may be variable and may be characterized by intellectual disability, choreoathetosis and/or behavior disorders (aggressiveness, agitation, hallucinations, automutilation), as well as pre- and postnatal growth retardation, microcephaly and/or speech impairment. Severe ketoacidosis and elevated urinary excretion of isoleucine metabolites are reported.