There are many different forms of Hypohidrotic Ectodermal dysplasia (HED) caused by different genetic mutations. In the case of the Xlhed it means that the genetic mutation has taken place on the “X” chromosome and is affecting the EDA gene.
It has been discovered that there are specific areas of the body that can be affected by this gene disorder. It is linked to abnormalities in the sweat producing glands, the growth and condition of the hair and nails, and the proper formation of the teeth.
It has also been noted that with some HED forms that there may be certain physical characteristics that can be noted. These includes dark circles and thin skin around the eye. The nose may appear to be depressed and the jaw may be small and narrow and the teeth will be small and pointed. Which of these characteristics are the most prominent or noticeable will depend on the form of HED that is present.
It has been determined that about 95% of those suffering from HED have the x linked form (xlhed). For absolute certainty, as to whether the disease exists in a child it requires molecular genetic testing as well as delving into the family history.
Further testing can, referred to as carrier testing, also be conducted/undergone. This may be done if it has been identified that this disease exists within a family based on the family history. Another advance that has been made in regards to the diagnosis of this condition is prenatal testing that can be done if a risk for the fetus having this disease has been identified.
Historical data also has helped to identify how frequent Xlhed can be. It is estimated that out of every 5,000 to 10,000 newborns one will present with this abnormality. However, the figures may be vague because many times the abnormality goes unnoticed at birth and may not be statistically reported.