For example, reduced gene dosage of Raldh2, the primary RA synthetic enzyme during establishment of initial hindbrain patterning, can ameliorate some phenotypes in mouse models of 22q11DS including CN V, thymus and fourth arch abnormalities (Guris et al., 2006; Karpinski et al., 2014; Ryckebusch et al., 2010). The gene discussed is ALDH1A2; the disease is 22q11.2 deletion syndrome.