Two novel ectodysplasin A gene mutations and prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (HED) is mainly caused by ectodysplasin A (EDA) gene mutation. Fetus with genetic deficiency of EDA can be prenatally corrected. This study aimed at revealing the pathogenesis of two HED families and making a prenatal diagnosis for one pregnant female carrier.

Genomic DNA was extracted from two HED patients and sequenced using whole exome sequencing (WES). The detected mutations were confirmed in patients and family members using Sanger sequencing. The expression of soluble ectodysplasin A1 (EDA1) protein was studied by western blot. The transcriptional activity of NF-κB pathway was tested by dual luciferase assay. The genomic DNA of fetus was extracted from shed chorion cells and EDA gene was screened through Sanger sequencing.

We identified two novel EDA mutations: c.1136T>C (p.Phe379Ser) and c.[866G>C;868A>T] (p.[Arg289Pro;Ser290Cys]). Further examinations revealed that these two mutated EDA1 proteins showed completely impaired solubility, and the transcriptional NF-κB activation induced by these missense mutant-type EDA1 proteins was significantly reduced compared with wild-type EDA1. Furthermore, the analysis of amniotic fluid samples from a pregnant heterozygote indicated that the fetus was a c.1136T>C mutation female carrier.

This study extended the mutation spectrum of X-linked hypohidrotic ectodermal dysplasia (XLHED) and applied prenatal diagnosis for the pregnant carrier, which can be helpful in genetic counseling, prenatal diagnosis, and intervention for the XLHED family.