Hypohidrotic ectodermal dysplasia (HED)

What happens in this disease?

In the womb, the skin, hair, nails, teeth and sweat glands develop from the same layer of cells. In this disease, one of the genes that controls this development is changed. The sweat glands are few or do not work. This is why the body has difficulty cooling itself. Intelligence and growth are usually normal.

Which symptoms can occur?

Symptoms usually become clearer in childhood.

• Reduced sweating; body temperature rising in the heat (common)
• Sparse, thin, light-colored hair (common)
• Missing, late-coming, small and pointed teeth (common)
• A prominent forehead, full lips, a flat bridge of the nose
• Thin, darker skin around the eyes
• Skin problems such as eczema
• Foul-smelling discharge and crusts in the nose (sometimes)

How is it diagnosed?

The diagnosis is usually made when the tooth and hair findings become clear. The doctor examines the person, counts the sweat pores or does a sweat test. A dental X-ray shows missing teeth. A genetic test confirms the diagnosis.

Treatment and care

Care is aimed at the symptoms and involves many specialists. The most important thing is to prevent overheating. A cool environment, plenty of water and cooling with a wet cloth are recommended. Early dental treatment, dentures and implants support eating and speech. Nasal crusts are cleaned by a specialist. Humidifying the air in the room helps. Artificial tears can be used for dry eyes. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

HED is most often X-linked. In this type, males are more severely affected. Women who are carriers may have mild signs, such as a few missing teeth or sparse hair. Less often, dominant or recessive inheritance is seen. In the recessive type, for a carrier couple, the chance of an affected child in each pregnancy is 1 in 4. Genetic counselling clarifies the risk in the family.