Primary screening for thalassemia and hemoglobinopathies usually involves an accurate blood count using an expensive electronic blood cell counter A cheaper alternative method was tested by using a modified osmotic fragility (OF) test and a modified dichlorophenolindophenol (DCIP) test. Altogether 423 pregnant Thai women participated in this project. Hemoglobin patterns and globin genotypes were determined using an automated high-performance liquid chromatography analyzer and polymerase chain reaction analysis of alpha- and beta-globin genes. Among the 423 subjects, 264 (62.4%) carried thalassemia genes. The combined OF and DCIP tests detected all pregnant carriers of the 3 clinically important thalassemias, ie, alpha0-thalassemia, beta-thalassemia, and hemoglobin E with a sensitivity of 100.0%, specificity of 87.1%, positive predictive value of 84.5%, and negative predictive value of 100.0%, which show more effectiveness than these values for the standard method based on RBC counts. A combination of modified OF and DCIP tests should prove useful and applicable to prenatal screening programs for thalassemia and hemoglobinopathies in communities with limited facilities and economic resources.
We describe hematologic and DNA characterization of hemoglobin (Hb) E homozygote with various forms of alpha-thalassemia in Thai individuals. Altogether, 131 unrelated adult subjects with Hb EE at routine Hb analysis were studied. Forty-two cases were found to carry alpha-thalassemia with ten different genotypes. These included 21 cases with alpha(+)-thalassemia heterozygote (-alpha(3.7)/alphaalpha), one case with alpha(+)-thalassemia heterozygote (-alpha(4.2)/alphaalpha), six cases with Hb Constant Spring heterozygote (alpha(CS)alpha/alphaalpha), four cases with homozygous alpha(+)-thalassemia (-alpha(3.7)/-alpha(3.7)), one case with homozygous alpha(+)-thalassemia (-alpha(4.2)/-alpha(4.2)), two cases with compound alpha(+)-thalassemia/Hb Constant Spring (-alpha(3.7)/alpha(CS)alpha), one case with compound alpha(+)-thalassemia/Hb Paksé (-alpha(3.7)/alpha(PS)alpha), four cases with alpha(0)-thalassemia heterozygote (--(SEA)/alphaalpha), and, unexpectedly, two cases with compound alpha(0)-thalassemia/alpha(+)-thalassemia [(--(SEA)/-alpha(3.7)) and (--(SEA)/-alpha(4.2))]. The hematological expression of these Hb E homozygotes with various forms of alpha-thalassemia was presented comparatively with those of the 89 cases of pure Hb E homozygotes. Overlapping levels of Hb E, Hb F, and other hematological parameters were observed which did not predict clinical severity, indicating a need for alpha-globin gene analysis for accurate diagnosis and improved genetic counseling.
We determined the prevalence of the H63D and the IVS5#1G-A HFE mutations in 370 (169 males and 201 females) Thai thalassemia carriers and 201 normal subjects. While no IVS5#1G-A mutation was found, the H63D heterozygosity was identified in 5.5% (11/201) of normal subjects and 7.3% (27/370) of thalassemia carriers. Within the thalassemic group, the medians (ranges) of serum ferritin were 217.5 ng/ml (20.1–424.3) and 169.8 ng/ml (3.9–3,536.0) in male subjects and 30.4 ng/ml (11.9–130.7) and 49.3 ng/ml (0.6–931.0) in female subjects with (HD) and without (HH) H63D mutation, respectively. The proportions of subjects with elevated ferritin were found to be 37.5% (6/16) for HD and 14.0% (18/129) for HH in male and 0% (0/11) for HD and 3.0% (5/164) for HH in female subjects, respectively. Statistical analysis of all the data revealed no significant difference. Among 14 Hb E/β-thalassemia patients, no difference in hematological data as well as serum ferritin levels was observed between those with (HD) and without (HH) H63D mutation. Therefore, the H63D heterozygosity has no significant effect on the serum ferritin level and screening for this HFE mutation in thalassemic patients is not recommended.
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