Detection and quantitation of the fetal hemoglobin variant Hb F-Malta-I in adults

A variant of fetal hemoglobin (Hb F-Malta-I) has been detected and quantitated in adult blood with a sensitive radioimmunoassay employing monospecific anti-sera. The concentration of Hb F-Malta-I was 0.002–0.05%, with an average value of 0.011%. The ratio of Hb F-Malta-I/Hb F in adults was about 4.8%, compared to a ratio of about 27% in the newborn. Since the F-Malta-I variant is a product of a mutated ^G? locus, which is one of the nonallelic structural genes directing the ? chain synthesis, its presence in blood of adults shows that the synthesis of this gene is not completely suppressed after birth, as was previously suggested.