Analysis of fetal blood using capillary electrophoresis system: a simple method for prenatal diagnosis of severe thalassemia diseases

Abstract

In Thailand where the total population is approximately 63 millions with 800 000 births per year, 30-40% of the peoples are carriers of thalassemia and hemoglobinopathies. These include 20-30% of a-thalassemia trait, 3-9% with b-thalassemia trait, 20-30% with Hb E (1). With such high prevalence, thalassemia syndromes are very common, leading to major health and socioeconomic problem of these countries. It is estimated that 1% of Thai population has thalassemia disease and each year there are more than 12 000 new births with thalassemia syndromes. The national prevention and control program of thalassemia has been implemented throughout the country. Three severe thalassemia diseases, targeted for prevention and control are Hb Bart's hydrops fetalis (homozygous a°-thalassemia), homozygous b-thalassemia and Hb E-b-thalassemia. If parents are both carriers, there is a 25% chance in each pregnancy that the child will be born with these thalassemia diseases. One objective of the prevention and control program is to prevent birth of new cases with these three severe thalassemia diseases. Carrier screening and prenatal diagnosis for couple at risk for these Abstract Introduction: Prenatal diagnosis of severe a-and b-thalasssemia diseases is usually performed by DNA analysis. Objective: To establish a simple method, we have evaluated the reliability of prenatal diagnosis by fetal blood analysis using automated capillary electrophoresis system. Methods: Forty-seven fetal blood specimens collected by cordocentesis at 18-28 wk of gestation were analyzed by the capillary electrophoresis system (Sebia). Fetal DNA was analyzed for respective thalassemia alleles by PCR. Results: Among 47 fetuses, 20 were at risk for the Hb Bart's hydrops fetalis. DNA analysis identified four cases of homozygous a°-thalassemia (SEA type). Hb analysis by the capillary electrophoresis demonstrated a major peak of Hb Bart's (78.4-81.3%), Hb H (0.8-1.4%) and minor peaks of presumably embryonic Hbs. No Hb F and Hb A was observed. The level of Hb Bart's was found to be 3.4-5.8% in unaffected heterozygote whereas normal fetus had no Hb Bart's. Among the remaining 27 fetuses at risk for Hb E-b-thalassemia, DNA analysis identified 12 affected fetuses. Hb analysis showed Hb F (94.9-98.9%) and Hb E (1.1-1.8%) without Hb A in all cases. The levels of Hb A were found to be (4.3-7.2%), (1.0-5.5%) and (2.1-3.9%) in normal, heterozygous Hb E and heterozygous b-thalassemia fetuses, respectively. Affected and unaffected fetuses could be easily distinguished. Conclusion: Capillary electrophoresis system is a simple and automated procedure for accurate prenatal diagnosis of severe thalassemia diseases which could readily be performed in routine setting.

Anemia, Iron Deficiency and Thalassemia among Adolescents in Northeast Thailand: Results from Two Independent Surveys

“…Initial screening for thalassemia and hemoglobinopathies was performed using the osmotic fragility and dichlorophenolindophenol test described elsewhere [7,8]. Hb analysis was performed using an automated Hb-LPLC analyzer (Hb-Gold; Drew Scientific Co., Ltd., Barrow-in-Furness, UK) and automated capillary zone electrophoresis (Capillarys 2; Sebia Co., Ltd., Lisses, France) [9]. Serum ferritin was assayed using chemiluminescent immunoassay on the Syncron LXi® 725 Access® Clinical system (Beckman Coulter, USA).…”

Routine screening for α-thalassaemia using an immunochromatographic strip assay for haemoglobin Bart's

“…b-thalassaemia heterozygosity is diagnosed in individuals with Hb A 2 A; Hb A 2 5 4.0%. 13,14 Polymerase chain reaction (PCR) and related methods are routinely utilized to identify b-thalassaemia mutations and six a-thalassaemia alleles common in Thailand (ie. a 0 -thalassaemia SEA & THAI deletions, a þ -thalassaemia 3.7 & 4.2 kb deletions, Hb Constant Spring and Hb Pakse´1 [5][6][7][8][9][10][11][12][13][14][15][16][17] ).…”

Cognitive Performance and Iron Status are Negatively Associated with Hookworm Infection in Cambodian Schoolchildren

“…43 Severe zinc deficiency was defined as serum zinc < 7.6 μmol/L. Diagnosis of hemoglobinopahy was performed using automated capillary zone electrophoresis (Capillarys 2: Sebia, Lisses, France) 44 at the Institute of Pasteur, Cambodia.…”