In a previous study, normocytic MCV was found at presentation in 48 (30%) of AAG patients, of whom 24 (50%) had concomitant iron deficiency indicated by abnormal transferrin saturation and serum ferritin concentration; further, stratification by age from under 20 years to over 60 years of age showed a regular and progressive increase in MCV and serum ferritin levels, but a decrease in cobalamin levels [97]. This evidence concerns the gene TF and Iron deficiency anemia.