Abstract: | IntroductionHypodontia, hypohidrosis, sparse hair and characteristic faces are the main characters of X-linked hypohidrotic ectodermal dysplasia (XLHED) which is caused by genetic ectodysplasin A (EDA) deficiency. Heterozygous female carriers tend to have mild to moderate XLHED phenotype, even though 30% of them present no obvious symptom.MethodsA large Chinese XLHED family was reported and the entire coding region and exon–intron boundaries of EDA gene were sequenced. To elucidate the mechanism for carriers’ tempered phenotype, we analyzed the methylation level on four sites of the promoter of EDA by the pyrosequencing system.ResultsA known frameshift mutation (c.573–574 insT) was found in this pedigree. Combined with the pedigrees we reported before, 120 samples comprised of 23 carrier females from 11 families and 97 healthy females were analyzed for the methylation state of EDA promoter. Within 95% confidence interval (CI), 18 (78.26%) carriers were hypermethylated at these 4 sites.ConclusionChinese XLHED carriers often have a hypermethylated EDA promoter. |