In particular, the “Down syndrome critical region (DSCR)”, considered as one of the main candidate regions to be responsible for most DS features, contains important candidate genes such as the dual-specificity tyrosine (Y)-phosphorylation regulated kinase 1 A (DYRK1A), the overexpression of which is believed to affect early thyroid morphogenesis [62,63]. The gene discussed is DYRK1A; the disease is Down syndrome.