Q. A 30-year-old Egyptian man comes to the ER because of a sudden episode of lower back pain with dark urine and yellowing of the eyes. He had cystitis 3 days ago which is being treated with nitrofurantoin. He mentions that this is not the first time he has suffered from these symptoms but he did not seek any medical treatment for the prior episodes. Physical examination reveals flank pain to palpation and an enlarged spleen to percussion and palpation. Blood smear shows small basophilic inclusions within erythrocytes in addition to RBCs that have varying numbers of semicircular portions removed from the membranes. What is the most likely diagnosis?