G6PD and Hyperbilirubinemia: The Child Health Epidemiology Reference Group (CHERG) modeling study estimates that 78% of cases of extreme hyperbilirubinemia are attributable to Rh disease, 6% to glucose 6-phosphate dehydrogenase deficiency (G6PD), 2% to moderate/late preterm birth, and 15% to other causes [19].