Hair shaft structures in EDAR induced ectodermal dysplasia

Mutations in the EDAR-gene cause hypohidrotic ectodermal dysplasia with defects in ectodermal appendage development including teeth, skin, exocrine glands and hair. Hair defects are sparsely described in genetically defined samples. The aim of this study was to investigate hair structures in three families with a heterozygous c.1072C > T mutation in the EDAR gene using scanning electron microscopy.

Three Swedish families, where some members had a known c.1072C > T mutation in the EDAR gene with an autosomal dominant inheritance (AD) were included (n = 37) of which 17 carried the mutation and 20 did not. Thirty-two age and gender matched not related individuals served as a reference group. Confirmation of the c.1072C > T mutation in the EDAR gene was performed by genomic sequencing. Hairs were subjected to blinded scanning electron microscopy examination and hair defects were categorized and scored.

The minimum and maximum diameters of hairs were lower in the mutation group compared to the reference group. Subjects in the mutation group had to greater extent deep deformations in hair shafts compared to the non-mutation group and the reference group (p < 0.001).

Individuals with a c.1072C > T mutation in the EDAR-gene displayed more hair shaft deformations confirming the role of EDAR for human hair follicle development and postnatal hair follicle cycling.