The high prevalence of diabetes mellitus type 2 and hypertension in Afro-Caribbeans in the West could be directly related to the incidence of G6PD deficiency in those populations.Although female carriers can have a mild form of G6PD deficiency (dependent on the degree of inactivation of the unaffected X chromosome – see lyonization), homozygous females have been described; in these females there is co-incidence of a rare immune disorder termed chronic granulomatous disease (CGD). Diagnosis
The diagnosis is generally suspected when patients from certain ethnic groups (see epidemiology) develop anemia, jaundice and symptoms of hemolysis after challenges from any of the above causes, especially when there is a positive family history.Generally, tests will include:
Complete blood count and reticulocyte count; in active G6PD deficiency, Heinz bodies can be seen in red blood cells on a blood film;
Liver enzymes (to exclude other causes of jaundice);
Lactate dehydrogenase (elevated in hemolysis and a marker of hemolytic severity)
Haptoglobin (decreased in hemolysis);
A "direct antiglobulin test" (Coombs test) – this should be negative, as hemolysis in G6PD is not immune-mediated;When there are sufficient grounds to suspect G6PD, a direct test for G6PD is the "Beutler fluorescent spot test", which has largely replaced an older test (the Motulsky dye-decolouration test). Other possibilities are direct DNA testing and/or sequencing of the G6PD gene.The Beutler fluorescent spot test is a rapid and inexpensive test that visually identifies NADPH produced by G6PD under ultraviolet light. When the blood spot does not fluoresce, the test is positive; it can be falsely negative in patients who are actively hemolysing.
However, a recent study revealed that G6PD deficiency increases the cardiovascular risk up to 70%. The risk conferred by G6PD deficiency is moderate compared with the impact of primary cardiovascular risk factors. Besides, a published review hypothesized that G6PD deficiency  could reduce the antiplatelet efficacy of clopidogrel (clopidogrel resistance). Epidemiology
G6PD deficiency is the second most common human enzyme defect after ALDH2 deficiency, being present in more than 400 million people worldwide. G6PD deficiency resulted in 4,100 deaths in 2013 and 3,400 deaths in 1990. African, Middle Eastern and South Asian people are affected the most, including those who have these ancestries. A side effect of this disease is that it confers protection against malaria, in particular the form of malaria caused by Plasmodium falciparum, the most deadly form of malaria. A similar relationship exists between malaria and sickle-cell disease. One theory to explain this is that cells infected with the Plasmodium parasite are cleared more rapidly by the spleen. This phenomenon might give G6PD deficiency carriers an evolutionary advantage by increasing their fitness in malarial endemic environments. In vitro studies have shown that the Plasmodium falciparum is very sensitive to oxidative damage. This is the basis for another theory, that is that the genetic defect confers resistance due to the fact that the G6PD-deficient host has a higher level of oxidative agents that, while generally tolerable by the host, are deadly to the parasite. History
The modern understanding of the condition began with the analysis of patients who exhibited sensitivity to primaquine.