SLC12A2 and Global developmental delay: The SLC12A2-c.2939A>T p.(E980V) variant has not been reported previously, however, a de novo SLC12A2-c.2938G>A p.(E980K) variant where the amino acid change from glutamic acid was to lysine instead of valine was found previously in a boy with bilateral HI, hypotonia, and developmental delay who also had an XYY karyotype [25] (Fig. 2B).