[Study on gene mutations of alpha-thalassemia in the South of China].
There is a high prevalence of thalassemia in the South of China. To explore the genotype of alpha-thalassemia as well as the distribution of alpha globin gene mutation in the South of China, 356 patients with heterozygote alpha(+) thalassemia, heterozygote alpha(0) or homozygote alpha(+) thalassemia and 78 patients with HbH were analyzed. The gene diagnosis methods including Gap-PCR, nested-PCR, PCR-RE, PCR-SSCP, 4P-ASPCR and DNA sequence analysis were used. The results showed that among 356 patients, 295 patients with --SEA/alphaalpha (82.87%), 1 patient with alphaalpha/alpha-alpha(3.7) (0.28%), 3 patients with alphaalpha/alpha-alpha(4.2) (0.84%), 3 patients with alphaalpha/alpha(CS)alpha (0.84%), 1 patient with alphaalpha/alphaalpha(QS) (0.28%) and 2 patients with alphaalpha/alpha(Westmead) alpha (0.56%) were found. The homozygote with -alpha(4.2) or -alpha(3.7) was not found. In 78 patients with HbH, 29 patients with --SEA/alphaalpha(-3.7) (37.2%), 20 patients with --SEA/alphaalpha(-4.2) (25.6%), 19 patients with --SEA/alphaalpha(CS) (24.3%), 2 patients with --SEA/alphaalpha(QS) (2.6%) were detected, and other remaiming 8 patients were needed to be defined. Among the non-defined 8 patients, the synonymous mutation with C-->G transversion (GCC-GCG) at codon 65 in the exon 2 of alpha 2-globin gene was detected in 2 unrelated HbH patients came from Guangxi province. Whether it correlated with the phenotype of HbH disease or it is only a single nucleotide polymorphism site (SNPs), should be confirmed in the future. In addition, a set of gene diagnosis methods based on PCR to screen deletion and non-deletion genotypes of alpha-thalassemia in Chinese was improved. A new method, 4P-ASPCR, to detect Hb CS and Hb QS was also developed. The method was verified to be more accurate, time-saving and economic. In conclusion, the genotypes of alpha-thalassemia in Chinese are very complicated, the genotypes of alpha-thalassemia in Chinese need to be further studied, the results of this research probably have practical significance for the gene diagnosis or antenatal diagnosis of alpha-thalassemia in the South of China.
Duan
Shan
S
Department of Medical Genetics, Sun Yat-sen Medical College, Sun Yat-sen University, Guangzhou 510089, China.
Li
Hong-Yi
HY
Chen
Zheng
Z
Chen
Su-Qin
SQ
Bi
Xiong-Jie
XJ
Chen
Lu-Ming
LM
Du
Chuan-Shu
CS
D001483:Base Sequence; D002681:China; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D017353:Gene Deletion; D005787:Gene Frequency; D005838:Genotype; D005914:Globins / Q000235:genetics; D006447:Hemoglobin H / Q000235:genetics; D006454:Hemoglobins / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D018807:Polymorphism, Single-Stranded Conformational; D017085:alpha-Thalassemia / Q000235:genetics / Q000473:pathology*
D006454:Hemoglobins; D006455:Hemoglobins, Abnormal; D005914:Globins; D004247:DNA; D006447:Hemoglobin H; C035541:Hemoglobin Constant Spring