A certain single-nucleotide polymorphism (SNP) rs3827760 (c.1109T4C; p.Val370Ala) in the gene EDA1R, a gain-of-function allele associated with hair thickness and shovel-shaped incisors that predominantly occurs in the Native American and East Asian population, was found to attenuate the severity of symptoms in at least one familial case of XLHED [11, 12]. The gene discussed is EDAR; the disease is X-linked hypohidrotic ectodermal dysplasia.