Edimer

Hypohidrotic Ectodermal Dysplasia (HED) is a rare genetic disorder diagnosed on the basis of fine, sparse hair (hypotrichosis); few and often pointed teeth (hypodontia); and diminished or absent sweat function (hypohidrosis). There are a number of secondary features of HED that may include a reduction in mucous glands in the pharynx, larynx, trachea and bronchi, dry eye symptoms, eczema, asthma and dry mucous membranes in the mouth and nose. HED is most commonly caused by an alteration in the ectodysplasin A gene, inherited on the X-chromosome (XLHED). Males with their single X-chromosome are fully affected by XLHED, while females inheriting one normal and one altered X-chromosome are variably affected.

XLHED is also known as Christ-Siemens-Touraine syndrome.

In the first years of life, XLHED-affected individuals are at risk for severe medical complications, most often associated with their inability to sweat, leading to hyperthermia, and their reduced mucous secretion predisposing them to respiratory infections. Through childhood the focus of medical care for XLHED patients may shift to the chronic skin issues and severe hypodontia with its associated medical and self-esteem issues. The average adult tooth count in male patients affected with XLHED is only 6, and the few remaining teeth often are conical or peg-like. Dentures may be prescribed as early as age 2-3 yrs to enhance feeding and growth and to begin to address what are often life-long psychosocial issues.

While many families and doctors have found ways to manage their symptoms over the years, currently there are no specific therapies for the treatment of XLHED.

For further information on XLHED please visit the following resources:

• Key Research Articles
• National Center for Biotechnology Information (NCBI) OMIM report on Ectodermal Dysplasia
• NIH Genetics Home Reference “Guide to Understanding Your Genetic Condition: HED”
• National Library of Medicine’s Genetics Home Reference Guide to Understanding Your Genetic Condition: HED