Analysis Of Genotypes Of 425 Patients With Thalassemia

Objective:To understand the types of gene mutation and hematology phenoyepes of thalassemia in Zunyi.Providing clinical evidence of the genetic screening,genetic counseling and prenatal disgnosis improving for this region.Methods:Analyzing the gene frequency,genotype and hematology characteristic of 425patients with the clear diagnosis of thalassemia in the Children Department of Hematology of Affiliated Hospital of Zunyi Medical College from January 2015 to January 2018.According to the different genotype,425 cases were divided into different groups.The genotypes were analysed by high throughput sequencing.Calculation and statistical analyses were performed by the SPSS 23.0.Comparison among several groups was compared using the one-way analysis of variance.The difference between two groups was conducted with the t test of two independent-samples.P<0.05 was considered statistically significant.Results:（1）324β-thalassemia（76.24%）and 82α-thalassemia（19.29%）cases were detected.15cases（3.53%）were diagnosed asαcompositeβ-thalassemia.4 cases（0.94%）suffered from thalassemia composite abmormal hemoglobin.（2）The top of five in sequences ofβ-thalassemia were CD17（37.53%）,CD41-42（26.77%）,IVS-2-654（22.57%）,CD26（4.20%）and CD43（3.15%）,and 1 case of SEA-HPFH was detected.There was 1 case with the new gene point mutation,they were as follows respectively:HBB:c.316-148G>T,HBA2:c.46G>A.（3）Inα-thalassemia genotypes,the most common genotype was--^SEA（62.50%）,followed by-α^3.7（20.19%）andα^CSα（14.42%）,and 1 case of--^THAI/ααwas detected.The common genotype-α^4.2 was undiscovered.（4）The Hb,MCV,MCH and MCHC of CD26（HbE）were higher than otherβ-thalassemia heterozygotes and there was significant difference in Hb,MCV,MCH and MCHC between CD26（HbE）and otherβ-thalassemia heterozygotes（P<0.05）.（5）57β-thalassemia cases were double heterozygotes and homozygotes.All of them were major patients.（6）20 cases were suffered from hemoglobin H disease.20 cases were divided into two groups:deletional HbH and nondeletional HbH.The RBC,Hb and MCHC of deletional HbH were higher than nondeletional HbH and MCV,MCH were lower than nondeletional HbH.There was significant difference in RBC,Hb,MCV,MCH and MCHC between two groups（P<0.05）.（7）15 cases were diagnosed asαcompositeβ-thalassemia.Hemoglobin of 12 cases were normal or mild and 2 cases were middle anemia.Another 1 case ofαcompositeβ-thalassemia was severe anemia.（8）The hematology phenotypes of 4 patients with thalassemia composite abmormal hemoglobin were normal or slightly reduced.Conclusions:（1）The most common thalassemia wasβ-thalassemia in this research.（2）The top of three in sequences ofβ-thalassemia were CD17,CD41-42 and IVS-2-654.The most common genotypes ofα-thalassemia were--^SEA和-α^3.7.And the-α^4.2 was rare.（3）The hematology phenotypes of CD26（HbE）,SEA-HPFH,--^THAI/ααand thalassemia composite abmormal hemoglobin disease were normal or slightly reduced.The asymptomatic patients and the genotypes which can not be detected by conventional methods should be diagnosed with high throughput sequencing.（4）The anemia of nondeletional HbH was more serious than the deletion HbH.Most of them were transfusion dependent.