Abstract
There are 4 common varieties of .alpha.-thalassemia, namely, Hb Bart''s (.gamma.4) hydrops fatalis syndrome, Hb H disease, ''severe'' heterozygous .alpha.-thalassemia or .alpha.-thal-1 trait and ''mild'' heterozygous .alpha.-thalassemia or .alpha.-thal-2 trait and a new form resulting from the deletion of 4, 3, 2 and 1, respectively, of the .alpha.-globin structural genes. The cord blood of 26 newborn Chinese children with 1 HbH parent and 1 normal parent were examined. The concentration of Hb Bart''s was not useful in differentiating the .alpha.-thal-1 from the .alpha.-thal-2 trait.