Whole-exome Sequencing Identified a Novel Hemizygous Missense Variant in the EDA Gene in an Iranian Patient Causing Hypohidrotic Ectodermal Dysplasia

Ectodermal dysplasia (ED) is a congenital heterogenic disorder caused by the defect in the ectoderm and its derivatives. This complex disorder has different subtypes, the most common form of which is hypohidrotic ectodermal dysplasia (HED).  Symptoms include spare hair, defects in sweat glands activity, abnormal teeth and dystrophic nails. In the present study, whole-exome sequencing was performed to identify disease-causing variants in an Iranian 4-year-old affected boy with sparse hairs, low eyelashes and eyebrows, reduced teeth, severe dry skin, and reduced sweat glands. We confirmed the pathogenicity and its novelty within silico tools. Identifying variant confirmation in the patient and segregation analysis in her family were performed using the Sanger sequencing method. A novel hemizygous missense variant [NM_001399.5: c.1001G>C; p. (Arg334Pro)] was identified within the EDA gene; and this is the third case of HED in Iran that is related to the EDA gene. The distinction between our patient’s indications and those recorded for a few past subjects may be due to the differences in the mutations involved.