[Genetic Analysis and Prenatal Diagnosis of Thalassemia in Couples of Childbearing Age in Quanzhou Region Fujian Province, China].

OBJECTIVE: To explore the genotypes and prenatal diagnosis of thalassemia in couples of childbearing age in Quanzhou, Fujian Province. METHODS: Blood routine and hemoglobin electrophoresis were performed for initial thalassemia screening in 76 328 couples in Quanzhou region from July 2017 to July 2020. The couples with positive initial screening results further underwent thalassemia gene test. Couples carrying homotypic thalassemia genes underwent prenatal diagnosis in the second trimester. RESULTS: Among 76 328 couples of childbearing age, 1 809 couples of positive initial thalassemia screening were identified, with the positive rate about 2.37%. Further results of genetic detection of the 1 809 couples showed that 985 cases were diagnosed as α- thalassemia, of which --sea/αα was the most frequency, followed by -α3.7/αα and ααQS/αα; 296 cases were diagnosed as ß-thalassemia, the most frequency mutations were 654M/N and 41-42M/N; 26 cases of compound α and ß-thalassemia were detected. In addition, 3 rare cases of thalassemia were detected, including --THAI/αα, SEA-HPFH, and -α6.9/--sea. Among them, 108 couples were confirmed as homologous thalassemia, with the detection rate about 5.97%, including 96 couples of homologous α-thalassemia, 9 couples of homologous ß-thalassemia, and 3 couples with one had compound α- and ß-thalassemia. Among them, 17 couples with homologous α-thalassemia underwent prenatal diagnosis in the second trimester, of which 1 case of Hb Bart's Hydrops Syndrome, 3 cases of HbH disease, 9 cases of silent thalassemia or α-thalassemia minor, and 4 cases of healthy fetuses were detected. Fetal chromosome karyotype analysis showed that 16 cases were normal and 1 case diagnosed as Down syndrome. CONCLUSION: Thalassemia screening in pre-marital and pre-pregnancy, and prenatal diagnosis can effectively reduce the birth of children with thalassemia intermediate and thalassemia major. It is necessary to perform chromosome karyotype analysis at the same time as prenatal diagnosis of thalassemia gene in order to avoid fetus with abnormal chromosome.

[Genetic Testing for Alpha and Beta Thalassemia in Children in Quanzhou Region of Fujian Province in China].

OBJECTIVE: To analyze the genotypes and distribution of thalassemia in children in Quanzhou Region so as to provide reference for the prevention and control of thalassemia. METHODS: A total of 1 302 children with suspected thalassemia were collected from January 2014 to April 2020 in Quanzhou Region. The deletional α-thalassemia was detected by Gap-PCR, and DNA reverse dot blot (RDB) hybridization was used to detect α- and ß-thalassemia mutations. RESULTS: In the 1 302 cases, 667 cases were identified as thalassemia carriers, and the positive detection rate was about 51.23%. Among them, 380 cases of α-thalassemia gene were detected, and --SEA/αα was the most common genotype with the composition rate about 69.21%. Forty-two cases were identified as HbH disease, and -α3.7/--SEA was the most common genotype. While, 274 cases were identified as ß-thalassemia, and ßIVS-Ⅱ-654/ßN (35.40%) and ßCD41-42/ßN (33.94%) were the most common genotypes. Seventeen cases of ß-thalassemia major/intermedia were identified, and the most common genotypes were ßIVS-Ⅱ-654/ßIVS-Ⅱ-654 and ßIVS-Ⅱ-654/ßCD17. Meanwhile, 13 cases of α- complex ß- thalassemia were detected. Among them, 1 case of ß-thalassemia gene rare mutation Term CD+32 was firstly detected in Fujian Province, and 1 case of CD14-15 mutation was firstly detected in Quanzhou Region. In addition, 3 cases of abnormal hemoglobin disease were identified, in which 2 cases were Hb Q-Thailand and 1 case was Hb G-Honolulu. CONCLUSION: There are various genotypes of thalassemia in children in Quanzhou Region, and many children with thalassemia major or intermedia. Therefore, further prevention and control of thalassemia need to be strengthened for reducing the birth of thalassemia major or intermedia.