EDA and hypohidrosis: One of the most well-characterized forms is hypohidrotic ectodermal dysplasia (HED), typically caused by variants in EDA (ectodysplasin A), EDAR (ectodysplasin A receptor), or EDARADD (EDAR-associated via death domain), and is defined by hypohidrosis, oligodontia with conical teeth, and sparse hair [2].