Molecular characterization of Hb S(C) beta-thalassemia in American blacks.
An extension of previous reports describing the molecular defects and hematological abnormalities in black patients with Hb S(C) beta-thalassemia living in the Southeastern United States is presented. As many as 58 patients with Hb S-beta(+)-thalassemia, 16 with Hb C-beta(+)-thalassemia and 12 with Hb S-beta(0) -thalassemia have been studied. Patients with Hb S(C) beta(+)-thalassemia type 2 (high Hb A values) were most common; the thalassemia was due to mutations in the promoter of the beta-globin gene [-88 (C----T) and -29 (A----G)] or at the polyadenylation signal (T----C). Two patients with lower Hb A values (type 1) carried a mutation in the first intron of the beta-globin gene (IVS-1-5: G----T). The simultaneous presence of an alpha-thalassemia -2(-alpha/) resulted in some modifications of the hematological parameters, but had a minimal effect on the clinical condition. Patients with Hb S-beta (0) thalassemia had lower hemoglobin values, lower number of red blood cells, and lower MCHC values and suffered more frequently from complications than the patients with Hb S-beta(+)-thalassemia. A total of 17 different beta-thalassemia mutations were observed in 128 chromosomes; two mild beta(+)-thalassemia mutations [-88(C----T) and -29(A----G)] account for more than 80% of the thalassemic chromosomes.
Gonzalez-Redondo
J M
JM
Department of Cell and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
Kutlar
A
A
Kutlar
F
F
McKie
V C
VC
McKie
K M
KM
Baysal
E
E
Huisman
T H
TH
D044383:Black People / Q000235:genetics*; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006801:Humans; D009154:Mutation; D013789:Thalassemia / Q000097:blood / Q000208:ethnology / Q000235:genetics*; D014481:United States; D001741:Black or African American
D006451:Hemoglobin, Sickle