Survey of cord blood hemoglobin in Japan and identification of two new gamma chain variants.

Two gamma chain variants were discovered during a survey of 2,569 cord bloods of Japanese. One was the first case with mutation of the T-gamma chain, i. e. Hb F Yamaguchi or gamma 80 (EF 4) Asp leads to Asn (75 Thr, 136 Ala). It comprised 33.6% of Hb F, an unusually high percentage for a gamma chain variant. The other concerned with the first report of substitution at E 16, i. e. Hb F Iwata or gamma 72 (E 16) Gly leads to Arg (75 Ile, 136 Ala). It comprised 11.0% which is comparable to the values usually reported in an A-gamma chain variant. No clinical consequences have been observed in association with the hemoglobin variants.