G6PD deficiency (favism)

G6PD is an enzyme that shields red blood cells from oxidative stress. When it's deficient, fava beans, certain drugs and infections can make red cells break down. It's X-linked, so it more often affects males.

Possible results

Normal G6PD. You don't carry this G6PD deficiency variant, so the enzyme that protects your red blood cells from oxidative stress works normally. Foods like fava beans and certain medications shouldn't pose the special risk they do for people with G6PD deficiency.

G6PD carrier. You carry one copy of the G6PD deficiency variant. Because this gene sits on the X chromosome, women with one copy are usually fine but can have somewhat reduced enzyme activity, and you can pass the variant on. In some situations your red cells may be a little more sensitive to certain drugs or fava beans.

G6PD deficient. You carry the G6PD deficiency variant on both copies (or, for men, on the single X). The enzyme that shields red blood cells from oxidative stress works poorly, so fava beans, certain medications (such as some antimalarials and sulfa drugs), and infections can make red cells break down. Knowing and avoiding your triggers is the main thing.

Evidence & sources

This variant appears in 16 published genetic studies: PubMed 23446634 · PubMed 23696099 · PubMed 28453575 · PubMed 28898252 · PubMed 31213470 · PubMed 33887194 · PubMed 34014839 · PubMed 34059833 · PubMed 34376796 · PubMed 36395887 · PubMed 36575460 · PubMed 38964323 · PubMed 39280063 · PubMed 39379762 · PubMed 40968291 · PubMed 41298473.

Related

Alpha-1 antitrypsin deficiency · Gaucher disease type 1 (carrier) · Hereditary hemochromatosis (HFE gene)