Trichothiodystrophy is a hereditary disorder characterized by brittle hair, which may be accompanied by a variety of other manifestations. It is sometimes called PIBIDS, a term that refers to the association of Photosensitivity Ichthyosis, Brittle hair, Intellectual impairment, Decreased fertility, and Short stature. Without photosensitivity the condition has been termed IBIDS, and without ichthyosis, BIDS. Many patients have recurrent infections, and abnormalities of the bone and teeth may also occur.
The defining feature of trichothiodystrophy is brittle hair, which is sulfur deficient and, when examined with a microscope and polarized light, demonstrates a characteristic light and dark (tiger tail) banding.