title: [Molecular detection and haematological analysis of heterozygotes in beta-thalassemia combining deletional alpha-thalassemia].
abstract: This study was aimed to investigate the prevalence and genotype distribution of heterozygotes in beta-thalassemia combining deletional alpha-thalassemia by using molecular detection and haematological methods. Three common deletions of alpha-thalassemia were detected by using gap-PCR. The mutations of beta-thalassemia were identified by using PCR with reverse dot blot hybridization. The routine analysis of blood cells was carried out. The results indicated that 15 cases from the 81 beta-thalassemia traits were found to be the compound heterozygosity for beta-thalassemia and alpha-thalassemia with 9 different types of gene defects with 18.52% detection rate. There were 6 cases (7.41%) of beta-thalassemia heterozygote combining alpha-thalassemia-1 gene (--(SEA)/alphaalpha), 8 cases (9.88%) combining with alpha-thalassemia-2 gene including 6 (7.41%) right ward deletion (-alpha(3.7)/alphaalpha) and 2 (2.47%) left ward deletion (-alpha(4.2)/alphaalpha), and 1 case (1.23%) combining deletional HbH gene (--(SEA)/-alpha(3.7)). No significant differences were found between beta-thalassemia heterozygotes combining deletional alpha-thalassemia and pure beta-thalassemia in all RBC parameters. It is concluded that the incidence of beta-thalassemia heterozygotes combining with deletional alpha-thalassemia is frequent in Wuzhou city. The hematological analysis can not give specificity for diagnosing these dual heterozygotes. Gap-PCR as a routine method for thalassemia screening has the advantages in reducing the possibility of failing to detect the combining heterozygosity for beta-thalassemia and alpha-thalassemia. It is more useful for genetic counselling and prenatal diagnosis of this disease.
authors.affiliation: Central Laboratory, Wuzhou Red Cross Hospital, Wuzhou 543002, China. cylzen@sohu.com
authors.forename: Yong-Lin
authors.initials: YL
authors.lastname: Cai
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Zheng
authors.forename: Min-Zhong
authors.initials: MZ
authors.lastname: Tang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Shao-Wen
authors.initials: SW
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D017353:Gene Deletion; D006580:Genetic Carrier Screening / Q000379:methods*; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D017085:alpha-Thalassemia / Q000235:genetics*; D017086:beta-Thalassemia / Q000235:genetics*