Adversely, the same EDA mutation can cause either HED or NTA; for example, we identified c.865C > T (p.R289C) in TNF binding domain of Eda in a 2-year-old hidrotic ED case with sparse hair and eruption of few peg shaped teeth (ED23); this EDA mutation was previously reported in isolated oligodontia cases only, thus, the involvement of other genetic factors could be suggested [41,49,51,52,53]. The gene discussed is TNF; the disease is hypohidrotic ectodermal dysplasia.