The enzymatic defect of G6PD deficiency, caused by mutations on the X-linked G6PD gene, is a known risk factor for increased levels of bilirubin after birth and it is associated with susceptibility to drug-induced haemolysis.6 Risk of severe NH is increased in both deficient and heterozygous newborns with abnormal phenotypes,7–9 and universal neonatal screening of G6PD deficiency is supported by WHO in populations where more than 3%–5% of boys are affected.10 The gene discussed is G6PD; the disease is G6PD deficiency.