all you wanted to know about G6 PD

Gbex says: Glucose-6-phosphate dehydrogenase deficiency is an X-linked recessive hereditary disease characterised by abnormally low levels of glucose-6-phosphate dehydrogenase (abbreviated G6PD or G6PDH), a metabolic enzyme involved in the pentose phosphate pathway, especially important in red blood cell metabolism.

Individuals with the disease may exhibit nonimmune hemolytic anemia in response to a number of causes, most commonly infection or exposure to certain medications or chemicals.

G6PD deficiency is closely linked to favism, a disorder characterized by a hemolytic reaction to consumption of broad beans, with a name derived from the Italian name of the broad bean (fava).

The name favism is sometimes used to refer to the enzyme deficiency as a whole, although this is misleading as not all people with G6PD deficiency will manifest a physically observable reaction to consumption of broad beans. G6PD deficiency is the most common human enzyme defect.

Most individuals with G6PD deficiency are asymptomatic.
Symptomatic patients are almost exclusively male, due to the X-linked pattern of inheritance, but female carriers can be clinically affected due to unfavorable Lyonization, where random inactivation of an X-chromosome in certain cells creates a population of G6PD-deficient red blood cells coexisting with normal red cells.

Abnormal red blood cell breakdown (hemolysis) in G6PD deficiency can manifest in a number of ways:

Prolonged neonatal jaundice, possibly leading to kernicterus (arguably the most serious complication of G6PD deficiency)
Hemolytic crises in response to:
Illness (especially infections)
Certain drugs (see below)
Certain foods, most notably broad beans
Certain chemicals
Diabetic ketoacidosis
Very severe crises can cause acute renal failure