Mutation Analysis Of The EDA Gene In A Hypohidrosis Ectodermal Dysplasia Family

Objective:A combination of techniques was conducted in a family with HED to identify the mutation gene,including multi-gene panal,high-throughput sequencing and Sanger sequencing.And predicted function of the mutation protein,assessed the variants’pathogenicity.Methods:We collected the clinical data of the family and analysesd the inherited pattern of HED.Extracted genomic DNA from blood samples of the index case and other 5 family members.A gene panel,which consists of exons of 541 genes of monogenic hereditary diseases,was used to capture the targeted gene of the index case.High-throughput sequencing was performed to detect the candidate gene pathogenic site.Sanger sequencing technology was used to identify the candidate gene pathogenic sites.Clustalx software was used to analyze the conservation of mutation sites.The function and region of the mutation protein were obtained by Uniprot database.Molecular modeling was used to predict the effect on the protein structure.Results:There were 2 male patients and one female carrier in this family.The inherited pattern of the disease is consisted with X-linked recessive.Results of high-throughput sequencing show a novel hemizygous frameshift mutation（NM₀01399:c.1077dupG:p.K359fs）in exon 8 of EDA.Results of Sanger sequencing confirmed the mutation of the index case,showing a hemizygous state.The same variant was only detected in his mother in the heterozygous state and his uncle as hemizygous.The father and other family member showed no this mutation gene.Clustalx software analysis showed that the EDA protein was completely conserved at the mutation site in 5 species.According to PyMOL analysis,the mutated EDA protein has six fewer β-sheets than the wild-type protein,conferring a remarkably different structure to the protein from that of the wild-type.Conclusion:In this family,there were 8 members in 3 generations,among which 2 patients were diagnosed as HED by genetic testing.This study discovered a new pathogenic mutation site in EDA gene which could be the pathogenic mutation of HED in this family;and extends our knowledge of the mutation spectrum of XLHED.