Characteristics of Silent Alpha Thalassemia Gene in Child-Bearing Adults in Guangdong / 中国实验血液学杂志

OBJECTIVE@#To investigate characteristics of silent alpha thalassemia genes in child-bearing adults in Guangdong, in order to provide data for the prevention and control of hemoglobin H disease.@*METHODS@#A total of 8 752 cases were collected from January 2016 to December 2020. Gap-PCR was used to detect the deletional of α-thalassemia mutations (-α3.7, -α4.2), while PCR reverse dot blot hybridization assay (RDB) was used to detect the non-deletional α-thalassemia mutations (Hb CS, Hb QS and Hb Westmead).@*RESULTS@#Among 8 752 subjects, 717 cases of silent α-thalassemia were detected, the detection rate was 8.19%, including 555 cases of deletional α-thalassemia (77.41%) and 162 cases of non-deletional α-thalassemia 22.59%. The mean corpuscular volume (MCV) of deletional silent α-thalassemia was (82.09±4.10) fl, and mean corpuscular hemoglobin (MCH) was (27.03±1.37) pg, which both were over the diagnostic cut-off value for thalassemia. The MCV of non-deletional silent α-thalassemia was (81.07±4.93) fl, and MCH was (26.77±2.20) pg. According to the diagnostic criteria, if using MCV<82 fl or (and) MCH<27 pg as a positive criteria for screening thalassemia in the childbearing age, the screening sensitivity was 53.14% and different in different genotype, among which ααQS/αα was 100%, -α3.7/αα, -α4.2/αα, ααCS/αα and ααWS/αα was 62.15%, 63.41%, 44.83% and 39.62%, respectively. Namely, nearly half the carriers of such mutations might have escaped detection as a result of their screening strategy.@*CONCLUSION@#When a couple is preparing for pregnancy, if one of them has been determined to be mild α-thalassemia or hemoglobin H disease, other half is necessary to carry out silent α thalassemia detection to prevent the birth of children with hemoglobin H disease even if MCV>82 fl and MCH>27 pg.

Hematological Characteristics of Different Genotypes of Thalassemia among Reproductive Population in Chongqing / 中国实验血液学杂志

OBJECTIVE@#To investigate the hematological characteristics and genotype distribution of thalassemia among people at reproductive age in Chongqing.@*METHODS@#Hematology analysis and capillary electrophoresis were performed in 29 145 participants at reproductive age. The patients with positive results were confirmed by thalassemia genotyping. Genotype distribution and characteristics of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and hba2 levels in thalassemia patients were analyzed.@*RESULTS@#--SEA/αα (45.10%), -α3.7/αα (39.31%) and -α4.2/αα (8.46%) were the most common genotypes of α-thalassemia, while CD17 (HBB: c. 52A>T) (31.67%), CD41-42 (HBB: c. 126-129 del TTCT) (26.87%) and IVS-Ⅱ-654 (HBB: c. 316-197 C>T) (24.21%) were the most common genotypes of β-thalassemia in Chongqing. In α-thalassemia ααCS/αα showed the lowest hba2 value (2.18±0.23)%, while --SEA/αα showed the lowest MCV (71.9±8.5) fl and MCH (22.7±3.3) pg value. The patients in βE (HBB: c. 79G>A) group showed comparatively higher values of MCV and MCH and significantly lower HbA and hba2 values than the other genotypes. There was no significant difference in HbA, hba2, MCV, MCH levels of the patients between pregnant group and non-pregnant group.@*CONCLUSIONS@#In Chongqing, there are differences in hematological characteristics among patients with different thalassemia genotypes. There is no significant effect of pregnancy on HbA, hba2, MCV and MCH has been found.

Quality, quantity and recovery of DNA content from routine blood samples and genotyping success rate: comparison between phenol chloroform method (PCM) with a new kit-based DNA extraction method (KBM)

Background: DNA extraction has become a baseline method for molecular biology studies. There are a variety of methods available for this purpose. Newer kit-based methods (KBM) are easy and less time consuming than traditional chemical methods of extraction like phenol chloroform method (PCM). Though estimates of quality from different methods are available in labels, this study compared the practical outcomes regarding quantity, quality, DNA recovery rate and assessed the outcomes at two different time points.Methods: This study was done as a secondary analysis from an ongoing project. The quantity and quality of DNA isolated from the same group of 100 deidentified blood samples by PCM and KBM were analysed using Multi analyzer and repeated after a period of 3 months. Genotyping of the samples were done by RT-PCR. The quantity, quality and amplification proportion were compared between two groups to reach the inference.Results: The median (range) concentration of DNA by PCM was 543.27 (960.59) µg/ml and that of KBM was 32.115 (36.73) µg/ml. The quality of DNA as measured by absorbance at 260/280 nm was 1.84 in PCM and 1.81 in KBM (p>0.05). Genotyping success rate was 78% in PCM and 98% in KBM (p = 0.002). The DNA recovery rate was 96% in PCM and 80% in KBM (p=0.014).Conclusions: The median concentration of DNA obtained from PCM was more compared to KBM. The quality of DNA was comparable in both the groups. The genotyping success rate was more in KBM group. The DNA recovery rate at 3 months was more in PCM group.