[Successful treatment of X-linked sideroblastic anemia with ALAS2 R452H mutation using vitamin B₆]

A 45-year-old man presented with fatigue and pain in the finger joints. Despite having a history of suspected sideroblastic anemia since the age of 18 years, he had not been followed up for years. Upon presentation, laboratory data revealed microcytic anemia and elevated serum ferritin levels. In addition, ringed sideroblasts were increased in the bone marrow. A liver biopsy revealed hemochromatosis and cirrhosis. Furthermore, genetic analysis revealed that he harbored the ALAS2 R452H mutation, leading to the diagnosis of X-linked sideroblastic anemia (XLSA). Accordingly, oral folate or vitamin (Vit) B₁₂ was administered, but his anemia did not respond. However, his hemoglobin level increased from 7 to 11 g/dl with an additional prescription of oral VitB₆, which facilitated the patient to undergo phlebotomy to ameliorate organ dysfunctions caused by iron overload. Previous research has revealed that ALAS2 R452 mutations confer poor responses to VitB₆ therapy. Hence, accrual of patients with an unexpectedly better response, which was observed in our case, may help elucidate the pathogenesis of and therapies for XLSA.