Björnstad syndrome in a patient with mental retardation: Pili torti or twisted hair can appear as an isolated defect, in association with other ectodermal defects, in association with other clinical features or can be acquired. Björnstad syndrome is a rare condition with apparent autosomal recessive inheritance, characterized by hearing loss and twisted hairs (pili torti). All patients with Björnstad syndrome reported thusfar have normal intelligence. We report on a patient with severe mental retardation and review the literature.