Pili torti: clinical findings, associated disorders, and new insights into mechanisms of hair twisting.

Pili torti is a hair shaft disorder characterized by hair that does not grow long and is easily broken; the hair often has a coarse or spangled appearance. A diagnosis is made by light microscopy of flattened hair twisted 1800 along its axis. Although pili torti may be isolated, it is commonly associated with other congenital defects and therefore, if identified, further evaluation for possible neurologic deficits and ectodermal disorders is an important part of the clinical evaluation. Alterations of the inner root sheath likely lead to the abnormal molding and twisting of the hair shaft. More recent research suggests that these alterations may occur in the face of mitochondrial dysfunction and may be influenced by the presence of reactive oxygen species.