G6PD Deficiency

G6PD ( Glucose-6-phosphate dehydrogenase ) deficiency (蚕豆症) is an X-linked recessive hereditary disease.  A person with G6PD deficiency is characterized by abnormally low levels of G6PD-ase enzyme involved in the pentose phosphate pathway, especially important in red blood cell metabolism.

G6PD deficiency present in > 400 million people worldwide.  It may have been around since antiquity, as favism was widely known in the Mediterranean 2,500 years ago.

Genetics

Signs & Symptoms

·Most individual with G6PD deficiency are asymptomatic.

·Symptomatic patients are almost exclusively male ; female patients are rare.

·Prolonged neonatal jaundice, possibly leading to kernicterus.

·Hemolytic crises in response to illness, certain drugs / food / chemicals.

·Diabetic ketoacidosis.

·Acute kidney injury ( AKI )

·Favism

Triggers

·Antimalarial drugs, eg. primaquine, pamaquine, chloroquine…

·Sulfonamides, eg sulfanilamide, sulfamethoxazole, mafenide…

·Analgesics, eg. aspirin, phenazopyridine, acetanilide…

·Non-sulfa antibiotics, eg. nalidixic acid, nitrofurantoin, isoniazid, dapsone, furazolidone…

·Henna 散沫花 ( Lawsonia inermis )

·Faba bean 蚕豆 ( Vicia faba )

·金银花 ( Lonicera japonica )

·Camphor 樟脑 ( extracted from Cinnamomum camphora, Rosmarinus officinalis, etc )

·Naphthalene, eg. Mothballs 臭丸

·Gentian violet / crystal violet / methyl violet / proctanine (紫药水/藍藥水)

·Tonic water ( contains quinine )

Diagnosis

·Complete blood count & rticulocyte count

·Liver enzymes test

·Lactate dehydrogenase test

·Haptoglobin test

·Coombs’ test

·Beutler fluorescent spot test

·Motulsky dye-decolorration test

Treatment

·Avoidance of certain drugs & foods that cause hemolysis.

·Vaccination against hepatitis A & B to prevent infection-induced attacks.

·Blood transfusions in case of acute hemolysis.

·Dialysis in case of acute renal failure.

·Splenectomy to remove spleen, the site of red cell destruction.

·Folic acid

Side effect

Immune against malaria caused by Plasmodium falciparum.