Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common 
hereditary enzymopathies worldwide. Mostly G6PD deficient cases are asymptomatic 
though they may have the risk of neonatal jaundice (NNJ) and acute intravascular 
hemolysis during oxidative stress. Chronic nonspherocytic hemolytic anemia 
(CNSHA) due to G6PD deficiency is rare. In Thailand, one case was reported 
40 years ago and by biochemical study this G6PD was reported to be a new variant 
G6PD Bangkok. We, herein, report two families with CNSHA due to G6PD deficiency. 
In the first family, we have been following up the clinical course of the 
patient with G6PD Bangkok. In addition to chronic hemolysis, he had three acute 
hemolytic episodes requiring blood transfusions during childhood period. 
Multiple gallstones were detected at the age of 27. His two daughters who 
inherited G6PD Bangkok from him and G6PD Vanua Lava from his wife are 
asymptomatic. Both of them had NNJ and persistent evidences of compensated 
hemolysis. Molecular analysis revealed a novel missense mutation 825 G→C 
predicting 275 Lys→Asn causing G6PD Bangkok. In the second family, two male 
siblings are affected. They had NNJ and several hemolytic episodes which 
required blood transfusions. On follow-up they have been diagnosed with chronic 
hemolysis as evidenced by reticulocytosis and indirect hyperbilirubinemia. 
Molecular analysis revealed combined missense mutations in exons 12 and 13. The 
first mutation was 1376 G→T predicting 459 Arg→Leu (known as G6PD Canton) and 
the second one was 1502 T→G predicting 501 Phe→Cys. We designated the resulting 
novel G6PD variant, G6PD Bangkok Noi.