When ID in HF is defined as either a serum ferritin of <100 μg/L or a serum ferritin of 100–300 μg/L along with a percentage of % transferrin saturation (TSat) (serum iron divided by transferrin levels multiplied by 100-%TSat) of <20%, about 60% of the anemic patients (24% of all HF patients) and about 40% of the non-anemic patients (also 24% of all HF patients) have ID [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]. The gene discussed is TF; the disease is hydrops fetalis.