Hypohidrotic Ectodermal Dysplasia is one of about 150 hereditary genetic birth defects which affect the ectoderm--hair, teeth, sweat glands, skin, nails and fingers, facial structure, vision and even hearing and the respiratory system. This disorder is found in approximately 1:17000 people. It is normally caused by an X recessive affected gene. Males are affected more frequently than females.
Hair may be sparse and brittle and slow growing. Facial features may be broadened and odd. Ears may be malformed. The eyes may have cataracts giving them a cloudy appearance. Fingernails may be thick and brittle. People affected by this condition also have less sweat glands and therefore cannot tolerate heat. One of the most attention-drawing features of this condition is how it affects the teeth. Teeth may be missing and/or pointed and fang-like with prominent canines.