Although the reasons for the heterogeneous phenotypes still remain unclear, the HDR syndrome itself has been shown to be caused by alterations that lead to GATA3 haploinsufficiency (Hasegawa et al., 1997; Van Esch et al., 2000; Muroya et al., 2001; Nesbit et al., 2004; Ferraris et al., 2009; Ohta et al., 2011; Stenson et al., 2017). Here, GATA3 is linked to Hypoparathyroidism - deafness - renal disease.