Vitamin B12, folate, and iron studies in homozygous beta thalassemia.

The efficacy of serum folate (SF), red blood cell folate (RCF), and serum B12 in diagnosing folate and B12 deficiency, and the effect of iron overload on hemoglobin, were studied in 157 cases of homozygous beta thalassemia (HBT). The patients had lower SF compared with normal subjects (NS) (P less than 0.001) and higher RCF than their parents (P less than 0.001) and NS (P less than 0.001). Forty percent of patients had both low SF (less than 3 ng/mL) and high RCF (greater than 600 ng/mL). Homozygous beta thalassemia patients are known to have folate deficiency. Yet, both folate and B12 deficiency status were similar in the authors' patients and NS. These deficiencies apparently were less in patients compared with their parents, who shared the same nutritional milieu (P less than 0.001). Mean hemoglobin in patients with iron overload (transferrin saturation, TS greater than 50%) was lower than in those without (P less than 0.005). The following is concluded: (1) diagnosis of folate and B12 deficiency based on SF, RCF and serum B12 is vitiated in HBT and needs a therapeutic trial; (2) iron overload of a magnitude indicated by TS greater than 50% can aggravate anemia in HBT.