[Diagnostic Value of HBA2 in Different Types of Thalassemia].

OBJECTIVE: To explore the diagnostic value of HBA2 in different types of thalassemia by analyzing the sensitivity and missed diagnosis rate of HBA2 in different types of thalassemia. METHODS: 1 178 couples in the department of women's health of Chongqing maternal and child health hospital were selected for pregnancy examination. Peripheral venous blood was extracted and analyzed for parallel blood routine test, hemoglobin capillary electrophoresis and thalassemia gene detection. RESULTS: A total of 265 cases of thalassemia gene carriers were screened out in 1 178 couples； 91.3% ß0 heterozygous thalassemia and 94.74% ß+ heterozygous thalassemia could be screened out using HBA2 > 3.5% as cut-off value; 30.19% stationary α-thalassemia and 66.07% standard α-thalassemia could be screened out using HBA2 < 2.5% as cut-off value. The rate of missed diagnosis of α-thalassemia and ß-thalassemia was 47% and 1.01% respectively when the blood routine screening is positive. CONCLUSION: HBA2 shows different diagnostic value for different types of α-thalassemia and ß-thalassemia. The sensitivity of HBA2 > 3.5% is higher than that of HBA2 < 2.5%. More attention should be paid to the further screening of patients with normal electrophoresis results when the blood routine screening is positive.

[Prevalence and Genotypes Analysis of Thalassemia Among People of Reproductive Age in Yuzhong District of Chongqing Based on Next-Generation Sequencing].

OBJECTIVE: To investigate the prevalence and gene distribution of thalassemia among people at reproductive age in yuzhong district, Chongqing. METHODS: 1000 pre -pregnancy examination couples in yuzhong district were investigated. Peripheral venous blood was extracted and next-generation sequencing was used to screen the thalassemia genes. RESULTS: Among the 1000 pregnant couples, the thalassemia gene carrying rate was 7.45%, the carrying rate of α and ß thalassemia genes were 4.60% and 2.10%, respectively. The most common α thalassemia genotypes in αα/-α3.7 (53.26%), αα/--SEA (23.91%), αα/-α4.2 (11.96%); and the most common genotypes in ß thalassemia genotypes were mainly Codons17 (A＞T) (26.19%)、Condon41/42 (-TTCT) (26.19%)、IVS-II-654 (C＞T) (14.29%) At the same time, 3 cases of α and ß complex thalassemia and 3 pairs of homotypic thalassemia genes were detected, more over, 12 cases of 5 new genes were found. CONCLUSION: Yuzhong district of Chongqing is a high incidence area of thalassemia, and the diversity of gene mutation types is relatively rich. Screening for thalassemia before pregnancy is of great significance to improve the quality of population.

[Comparision of the Efficacy of Different Thalassemia Screening Strategies Used for the Couple of Pre-Pregnancy in Yuzhong District of Chongqing City].

OBJECTIVE: To compare the efficacy of different thalassemia screening strategies used for the couple of pre-pregnancy. METHODS: A total of 1 159 couples were recruited in Chongqing health center for women and children from January 2019 to June 2019. Routine blood test, hemoglobin test and thalassemia gene test were performed for all the coulpes. The efficacy of thalassemia screening strategies were compared. Strategy 1: Hemoglobin was tested if the woman's MCV <80 fl and/or MCH <27 pg, and test for thalassemia genes was required further according to the result of hemoglobin test. If the woman was a thalassemia carrier, it is recommended that the man would receive the corresponding thalassemia gene test, and if the man carried the same type of thalassemia gene, so it meant positive. Strategy 2: the woman's blood cut-off value was MCV<82 fl and/or MCH<27 pg, and the follow-up procedure was the same as strategy 1. Strategy 3: If both of cople showed MCV (<80 fl) and/or MCH (<27 pg), the couple would be tested for hemoglobin electrophoresis, and if both of the couple showed abnomal result of hemoglobin electrophoresis, the couple would be tested for thalassemia gene. If the couple carried the same thalassemia gene, it meant positive. Strategy 4: If one of the couple or both of them showed MCV (<80 fl) and/or MCH (<27 pg), the couple would be tested for hemoglobin electrophoresis, if the couple showed MCV (<80 fl) and/or MCH (<27 pg) and/or the abnormal result of hemoglobin test, genetic test for thalassemia test were performed. RESULTS: A total of 15 couples were thalassemia positive. According to the ROC curve, the area under the curve of strategy 2 was the largest but the cost was the highest. The area under the curve of strategy 4 was slightly less than that of strategy 2, but the cost was lower. CONCLUSION: Strategy 4 is recommended in the case of high degree of male cooperation and strategy 2 is recommended in the case of low degree of male cooperation.