The family history showed no cases of jaundice or AHA, but during the laboratory investigation for the analysis of G6PD enzyme activity, she was found to be heterozygous for the 563 C > T mutation of the Mediterranean variant, with an activity of 2.5 U/g Hb (normal range: 4.6–13.5 U/g Hb). The gene discussed is G6PD; the disease is Jaundice.