EDA and ectodermal dysplasia syndrome: Overexpression of Eda in mice results in hypoplastic amelogenesis imperfecta (Mustonen et al., 2003); in humans, mutations in either EDA or EDAR have been found in hypohidrotic ectodermal dysplasia and isolated tooth agenesis, but not in amelogenesis imperfecta (Shen et al., 2019; Wright et al., 2019; Yu et al., 2019; Andreoni et al., 2021).