This is a 29 year old man who was diagnosed with pyruvate kinase (PK) deficiency early in childhood. He had a splenectomy at age 3, and was started on regular red cell transfusions a year later owing to the development of frontal bossing, maxillary hyperplasia and chronic headaches. He states that his baseline hemoglobin is about 7-8 g /dL, though it tends to fall during concurrent illness when he develops transient jaundice and his urine turns a dark color. He started oral iron chelation several years ago, but has been poorly compliant with the medication. He has had 2 liver biopsies to monitor for iron overload, and he has been followed with intermittent MRI of the liver and heart. He has received appropriate vaccinations post splenectomy. He has occasional colicky right abdominal pain after meals. A recent abdominal ultrasound revealed the presence of multiple gallstones. He currently denies fatigue, shortness of breath, chest pain or other symptoms of anemia. He denies symptoms of arthralgia and hypogonadism. He has no other active medical problems. There is no family history of PK deficiency or other hematological conditions. He is a non-smoker and denies any alcohol intake. He works in computer software. He is taking folic acid. He has no known allergies to drugs.