Search

Objective: To perform molecular diagnosis and pedigree analysis for one case with α-thalassemia who does not conform to the genetic laws, and explore the effects of a newly discovered rare mutation ( HBA2:c.*12G>A ) on clinical phenotypes., Methods: Blood samples of the proband and her family members were collected for blood routine analysis, and the hemoglobin components were analyzed by capillary electrophoresis. The common α- and β-globin gene loci in Chinese population were detected by conventional techniques (Gap-PCR, RDB-PCR). The α-globin gene sequences ( HBA1, HBA2 ) were analyzed by Sanger sequencing., Results: By analyzing the test results of proband and her family members, the genotype of the proband was -α 3.7 / HBA2:c.*12G>A , her father was HBA2:c.*12G>A heterozygous mutation carrier., Conclusion: This study identifies a rare α-globin gene mutation ( HBA2:c.*12G>A ) that has not been reported before. It is found that heterozygous mutation carriers present with static α-thalassemia.

Objective: To investigate two cases of rare pathogenic genes, initiation codon mutations in HBA2 gene, combined with Southeast Asian deletion and their family members to understand the relationship of HBA2:c.2T>C and HBA2:c.2delT mutations with clinical phenotype., Methods: The peripheral blood of family members was obtained for blood cell analysis and capillary electrophoresis hemoglobin analysis. Gap-PCR and reverse dot blotting (RDB) were used to detect common types of mutations in ɑ-thalassaemia gene. Sanger sequencing was used to analyze HBA1 and HBA2 gene sequence., Results: Two proband genotypes were identified as --SEA/αα with HBA2:c.2T>C and --SEA/αα with HBA2:c.2delT . HBA2:c.2T>C/WT and HBA2:c.2delT/WT was detected in family members. They all presented with microcytic hypochromic anemia., Conclusion: When HBA2:c.2T>C and HBA2:c.2delT are heterozygous that can lead to static α-thalassemia phenotype, and when combined with mild α-thalassemia, they can lead to the clinical manifestations of hemoglobin H disease. This study provides a basis for genetic counseling.

Objective: To proceed the clinical evaluation of DNA microarray for thalassemia gene detection., Methods: Peripheral blood samples of 166 thalassemia gene test subjects were collected and tested for thalassemia genes by microarray chip method and Gap-PCR method combined with PCR-reverse dot blot hybridization method according to double-blind control test. The specificity, sensitivity, positive predictive value, negative predictive value, and total coincidence rate of the microarray chip method were evaluated. When the two methods were inconsistent, multiplex ligation dependent probe amplification (MLPA) was used to verify the deletional α-thalassemia., Results: Compared with Gap-PCR method, specificity, sensitivity, positive predictive value, negative predictive value, Youden index, and total coincidence rate of microarray chip method was 100% (70/70), 96.88% (93/96), 100% (93/93), 95.89% (70/73), 0.969, and 97.59% (162/166), respectively, while compared with PCR-reverse dot blot hybridization method was 100% (125/125), 100% (41/41), 100% (41/41), 100% (125/125), 1, and 100% (166/166), respectively., Conclusion: The microarray chip method for α-thalassemia gene detection shows the advantages of high specificity, sensitivity, and throughput.

Objective: To perform dried blood spots thalassemia gene detection in patients with positive blood phenotypes by microarray technology, and evaluate its value in clinical detection., Methods: DNA samples were extracted from dried blood spots of 410 patients. Microarray technology was used to detect 3 deletion and 3 non-deletion types of α-thalassemia and 19 β-thalassemia point mutations which were common gene mutions in China., Results: There were 357 positive cases in all the 410 tested samples with the positive rate 87.07%, among which 299 cases (72.93%) carried deletion or point mutations of α-thalassemia, 29 cases (7.07%) carried point mutations of β-thalassemia and 29 cases (7.07%) carried gene mutations of complex αβ-thalassemia syndrome. The mutations of α-thalassemia were involved with -- SEA heterozygous deletion (177 cases, 59.2%), α CS heterozygote (60 cases, 20.07%) and several other genotypes. The common mutations of β- thalassemia were involved with β CD41-42 heterozygote (10 cases, 34.48%) and β CD17 heterozygote (9 cases, 31.03%). The mutations of complex αβ-thalassemia syndrome were mainly involved with -- SEA /αα+β CD17 /β N (7 cases, 24.14%), α CS α/αα + β CD41-42 /β N (3 cases, 10.34%) and -α 4.2 /αα + β CD17 /β N (3 cases, 10.34%)., Conclusion: The most common genetic mutations are -- SEA for α-thalassemia and CD41-42 for β-thalassemia in Liuzhou, Guangxi Zhuang Autonomous Region. A and β-thalassemia can be detected at the same time by microarray chip technology in a high throughput manner.