Thalassemia screening and genotyping in Southwest Guizhou Autonomous Prefecture of Guizhou Province / 中华地方病学杂志

Objective:To analyze the thalassemia screening and genotyping in Southwest Guizhou Autonomous Prefecture (referred it as Qianxinan Prefecture), this essay provides the theoretical reference for clinical diagnosis of thalassemia and suspicious cases.Methods:The pregnant women, spouses and neonates who were screened for thalassemia gene in Qian Xi Nan People's Hospital from January 2016 to December 2020 were selected as the research subjects, and peripheral blood or umbilical cord blood samples were collected to extract DNA. The gap-polymerase chain reaction (Gap-PCR) and next-generation sequencing (NGS) technology were used to screen thalassemia, and ArcMap 10.8 software was adopted to map the local spatial distribution of thalassemia based on the screening data.Results:A total of 67 185 cases of people from various regions in Qianxinan Prefecture were screened, and 8 202 cases of thalassemia gene carriers were detected, with a total detection rate of 12.21%. Among them, 5 660 cases of α-thalassemia, with a detection rate of 8.42%; 2 132 cases of β-thalassemia, with a detection rate of 3.17%; 410 cases of αβ complex thalassemia, with a detection rate of 0.61%. In the detection of thalassemia genes, 27 genotypes of α-thalassemia were detected, mainly αα/-α 3.7, accounting for 41.13% (2 328/5 660); 33 genotypes of β-thalassemia were detected, mainly β CD17(A>T)/β A, accounting for 44.09% (940/2 132); 55 genotypes of αβ complex thalassemia were detected, and αα/-α 3.7 complexed β CD17(A>T)/β A dominated, accounting for 21.22% (87/410). There were high incidence areas in the spatial distribution of thalassemia, which were Wangmo County and Ceheng County, and the detection rate was 26.76% (1 438/5 374), 24.39% (1 314/5 387), respectively. Conclusions:The detection rate of thalassemia gene in Qianxinan Prefecture is relatively high, mainly αα/-α 3.7 genotype of α-thalassemia. Wangmo County and Ceheng County are high-incidence areas of thalassemia, and screening efforts should be continued.

The value of combined tests of hemoglobin electrophoresis and genetic testing in neonatal cord blood screening for β-thalassemia / 国际检验医学杂志

Objective To explore the clinic utility of Hb A level in neonatal cord blood screening for β‐thalassemia .Methods A total of 1 599 neonatal cord specimens whose parents were carriers of β‐thalassemia prenatal diagnosised by routine molecular genet‐ic were collected by cordocentesis .These samples were analyzed by the capillary electrophoresis system (Sebia) .Results Among 1 599 fetuses ,186 were diagnosed as β‐thalassemia carriers ,68 were β‐thalasseima intermedia/major .ROC analysis demonstrated that the optimal cutoff value for identifying β‐thalassemia carrier from the Hb A level was 5 .15% (sensitivity = 83 .9% , specificity = 82 .3% ) ,and that was 3 .2% for β‐thalasseima intermedia/major (sensitivity = 100 .0% ,specificity = 99 .4% ) .Conclu‐sion The Hb A level of cord blood was an effective marker to screen the β‐thalassemia for fetuses and is therefore well‐suited for clinical diagnostic use .

Genotypic influence of alpha-deletions on the phenotype of Indian sickle cell anemia patients

BACKGROUND: Some reports have shown that co-inheritance of alpha-thalassemia and sickle cell disease improves hematological parameters and results in a relatively mild clinical picture for patients; however, the exact molecular basis and clinical significance of the interaction between alpha-thalassemia and sickle cell disease in India has not yet been described. There is little agreement on the clinical effects of alpha-thalassemia on the phenotype of sickle cell disease. METHODS: Complete blood count and red cell indices were measured by an automated cell analyzer. Quantitative assessment of hemoglobin variants HbF, HbA, HbA2, and HbS was performed by high performance liquid chromatography (HPLC). DNA extraction was performed using the phenol-chloroform method, and molecular study for common alpha-deletions was done by gap-PCR. RESULTS: Out of 60 sickle cell anemia patients, the alpha-thalassemia genotype was found in 18 patients. Three patients had the triplicated alpha-genotype (Anti alpha-3.7 kb), and the remaining patients did not have alpha-deletions. This study indicates that patients with co-existing alpha-thalassemia and sickle cell disease had a mild phenotype, significantly improved hematological parameters, and fewer blood transfusions than the patients with sickle cell anemia without co-existing alpha-deletions. CONCLUSION: Co-existence of alpha-thalassemia and sickle cell anemia has significant effects on the phenotype of Indian sickle cell patients.

Renal impairment in  thalassemia major patients receiving repeated blood transfusion.

β-thalassemia major is a disease caused by β polypeptide chain synthesis disorder which is inherited in an autosomal recessive manner from both parents and which is marked by little or no β-globin chain synthesis. Treatment for β-thalassemia major patients is by giving repeated blood transfusions, which causes iron accumulation, leading to hemochromatosis. Iron accumulation can occur in various body organ, including the kidneys. The aim of this study was to investigate the existence of renal impairment in β-thalassemia major patients. The subjects of this study were β-thalassemia major patients aged 15 - 28 years old who had received 6 units of packed red cells or more within 6 months. In this study, urine and serum samples of the subjects were taken and examined. Assay of serum iron was performed with Hitachi 737. Results were that 94.7% patients showed an increase in transferrin saturation and 40% of them had hemochromatosis; 73.4% had microalbuminuria; 1.3% had albuminuria and 21.3% had increased urinary β2- microglobulin (β2-m). A total of 78.6% of patients showed renal impairment. Conclusion of this study suggested that glomerular dysfunction happens in an earlier stage of the disease process. The high incidence of microalbuminuria is also attributed to defective ability of the proximal tubular cells to reabsorb protein besides dysfunction of the glomeruli.