The occurrence of different levels of ^Gγ chain and of the ^Aγ^T variant of fetal hemoglobin in newborn babies from several countries

Abstract

The gamma chain compositions of the fetal hemoglobins of 2453 newborn babies from East Asian countries (1350 babies), from Italy, Yugoslavia, Bulgaria, and Georgia (417 Caucasian babies), and 686 black babies from Georgia were determined by high pressure liquid chromatography. Unusual results for a limited number of babies were confirmed by chemical analyses, and were evaluated further by family studies. Statistical analyses indicated high gene frequencies for the A gamma T chain in Italian (f = 0.237), Yugoslavian and Bulgarian (f = 0.238), and white Georgia babies (f = 0.224), a lower frequency in Japan (f = 0.178), and India (f = 0.173), and particularly in mainland China (f = 0.079). The A gamma T gene frequency in normal (AA) Black babies was 0.102. When a beta S or beta C mutation was also present this frequency was greatly decreased, particularly in babies with the AC condition (f = 0.036). These results suggest the near absence of the A gamma T mutation on the chromosome also carrying the beta C determinant. Most babies had the expected G gamma values which vary between 60 and 80%, but several (mainly black) babies had higher values (between 80 and 90%), while one normal black baby had a G gamma value of (nearly) 100%. This condition may be a form of A gamma +1-thalassemia and has been discussed in detail elsewhere (Blood 58:491-500, 1981). Thirty-five clinically normal (mainly Chinese, Indian, and Japanese) babies had G gamma values of about 40%. Twenty-six babies had A gamma I values of about 60%, while the remaining nine babies had A gamma T and A gamma I chains in a ratio of either 1 to 2 or 1 to 1. Two additional newborns did not produce any G gamma chains, but had only A gamma I chains or A gamma T chains. Family studies failed to indicate a specific hematological abnormality. These unusual ratios between the G gamma and A gamma (either A gamma I or A gamma T) chains have led to speculations regarding possible genetic abnormalities present in these infants.

Hematological Values of 163 Normal Fetuses between 18 and 30 Weeks of Gestation

“…If this foreign population is withdrawn, the frequency of heterozygote and homozygote fetuses for H b F Sardinia is 36% for the French population. This is vely close to previous data for Caucasian newborns in the United States (25) and in the Netherlands (26). H b Bart's was detected in a group of 13 fetuses.…”

“…Other recent studies have permitted identification of a large number of such variants. which may be more frequent than previously thought (25). In the small number of cases in which ferritin was evaluated, no large differences were seen between individuals of varying gestational age.…”

HB F‐Yamaguchi (γ75THR, γ80ASN, γ136ALA) is associated with Gγ‐thalassemia

“…The ratio of the Gy and Ay chains in the Hb F of newborn babies averages about 7 to 3, but quite a few normal Japanese, Chinese, and Indian newborns were found to have a reversed ratio of 4 to 6, while two babies had Ay chains only [8]. This ' 7-thalassemia-like condition is characterized by a decreased level of Hb F which averages about 50% in the homozygote, 30% in the heterozygote, and 20% in the normal newborn [8].…”

Adult Hemoglobin Levels in Newborn Babies from Different Countries and in Babies with Some Significant Hemoglobinopathies

“…During the course of studies for y-or /I-globin gene anomalies, including y-globin gene triplications or deletions [12][13][14], y-globin gene mutants [15,16], and /?-or 5/J-thalassemia [13,16], it was possible to quanti tate Hb A in cord blood samples from relatively large numbers of normal newborn babies from Italy (Sardi nia), Yugoslavia (Macedonia), Turkey (Adana), Ja pan (Kurashiki City), and China (Beijing). The possi- …”