Hypohidrotic ectodermal dysplasia with immune deficiency (HED-ID) is a disorder that is allelic to IP. Affected males exhibit hypotrichosis with fine, sparse, and light-colored scalp and body hair. Patients show a decreased ability to sweat, which often leads to severe heat intolerance. In addition, hypodontia and conical or peg shaped teeth are also observed in affected individuals. Facial features are characterized by dark pigmented skin around the eyes, a saddle nose, and full lips. Defects in secretions from the lacrimal, meibomian, and other secretory glands result in thick nasal secretion and cerumen. Absent or accessory nipples are not uncommon. These patients also present with recurrent infections of the digestive tract, respiratory tract, and skin infections that may result in hospitalizations.