G1ucose−6−ph o s p hat e dehydrogenase deficiency causes haemolytic anaemia, which occurs when red blood cells are destroyed faster than the body can replace them. Related Theory Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a condition in which red blood cells break down when the body is exposed to certain drugs or the stress of infection. It is hereditary, which means it is passed down in families.