The Research On Non-deletion Hereditary Persistence Of Fetal Hemoglobin Co-Inherited With β-Thalassemia

Objective:To investigate the effects of non-deletion hereditary persistence of fetal hemoglobin（nd-HPFH）on laboartory findings ofβ-thalassemia heterozygotes and homozygotes/double heterozygotes cases,for beter understanding the genetic counseling and diagnosis onβ-thalassemia.Medthod:Patients admitted to the First Affiliated Hospital of Guangxi Meddical University during October 2017 to June 2018,were involved in this study.The hematologic data and hemoglobin level were obtained by routine blood test and hemoglobin analysis.Theβ-thalassemia genotypes were detected by fluorescence PCR melting curve method;and theγ-globin gene promoter sequences were analyzed by DNA sequencing According to the genotypes ofβ-globin gene mutation and compound nd-HPFH,cases were divided into two groups,one forβ-thalassemia heterozygotes and another forβ-thalassemia homozygotes/double heterozygotes.Cases withα-thalassemia had been excluded from the groups.Results:1.General data:A total of 583 cases participated in this study.536 cases of heterozygousβ-thalassemiaweredetected,including453casesofβ⁰-thalassemia heterozygotes,83 cases ofβ⁺-thalassemia heterozygotes,of which 159 cases were compound with nd-HPFH.A total of 47 cases ofβ-thalassemia homozygotes/double heterozygotes were detected,including 5cases ofβ⁺/β⁺-thalassemia homozygotes/double heterozygotes,23 cases ofβ⁺/β⁰-thalassemia double heterozygote,and 19 cases of ofβ⁰/β⁰-thalassemia homozygotes/double heterozygotes,of which 21 cases were compounded with nd-HPFH.2.Results of blood routine analysis:The study found that the mean red blood cell hemoglobin（MCH）and mean red blood cell volume（MCV）in the group of cases for nd-HPFH compoundingβ-thalassemia heterozygotes were higher than those of simpleβ-thalassemia heterozygotes group,includingβ⁰-thalassemia andβ⁺-thalassemia heterozygotes（P<0.05）.The indicates of RBC,Hb and HCT in the group of cases with nd-HPFH compoundingβ-thalassemia homozygous/double heterozygotes were higher than those of simpleβ-thalassemia homozygotes/double heterozygotes group（P<0.05）.In nd-HPFH compoundingβ⁺/β⁰-thalassemia double heterozygotes group,the indicates of Hb,RBC,and HCT were higher than those of the simpleβ⁺/β⁰-thalassemia double heterozygote group（P<0.05）.While in the group of nd-HPFH comploundingβ⁰/β⁰-thalassemia homozygotes/double heterozygotes,only Hb was elevated,compared with the group of simpleβ⁰/β⁰-thalassemia homozygotes/double heterozygotes.3.Results of hemoglobin analysis:the HbF of nd-HPFH compoundingβ-thalassemia heterozygotes group was higher than that of simpleβ-thalassemia heterozygotes group（P<0.05）.Among which there were different effects on nd-HPFH compounding simpleβ⁺-thalassemia heterozygotes and nd-HPFH compoundingβ⁰-thalassemia heterozygotes.For HbF and HbA₂,their levels in the group of nd-HPFH compoundingβ⁺-thalassemia heterozygotes were higher than those in the group of simpleβ⁺-thalassemia heterozygotes（P<0.05）.The HbF level of the nd-HPFH comploundingβ⁰-thalassemia heterozygotes was higher than that of nd-HPFH compoundingβ⁰-thalassemia heterozygotes group（P<0.05）.The hemoglobin analysis showed no significant difference between the group of nd-HPFH compoundingβ-thalassmia homozygotes/double heterozygotes and group of simpleβ-thalassemia homozygotes/double heterozygotes.4.β-globin gene analysis results:the genotypes ofβ-thalassemia heterozygotes were as follows:57 cases of CD41-42（-TTCT）,43 cases of-28（A>G）,28 cases CD17（A>T）,14 cases of IVS-I-1（G>T）,7 cases of IVS-II-654（C>T）,5 cases of CD71-72（+A）,3 cases of CD27-28（+C）and 2 cases of CD37（G>A）.The genotypes ofβ-thalassemia homozygotes/double heterozygotes were detected as follows:6 cases ofβ^-28/β^CD17,5 cases ofβ^-28/β^{CD 41-42},4 cases ofβ^IVS-I-1/β^CD41-42,3 cases ofβ^CD41-42/β^CD17,1 case ofβ^IVS-II-654/β^CD27-28,1 case ofβ^IVS-II-654/βCD 41-42 and 1 case ofβIVS-II-654/β-28.5.γ-globin gene analysis results:159 cases of nd-HPFH compoundingβ-thalassemia heterozygotes were detected.Among them,75 cases were ^Aγ-225^-222 deletetional mutation heterozygotes.62 cases were ^Gγ-158C>T heterozygotes.10 cases were ^Gγ-158C>T mutation homozygotes.2 cases were ^Aγ-318G>T homozygotes.1 case was ^Aγ-369G>C mutation homozygote.1 case was ^Gγ-256C>T homozygote.1 case was ^Gγ-256A>G heterozygote.5 cases were double heterozygotes for ^Gγ-158C>T and ^Aγ-225^-222 deletional mutation.and2 cases for ^Aγ-158C>T and ^Gγ-158C>T heterozygotes.A total of 21 cases of nd-HPFH compoundingβ-thalassemia homozygous/double heterozygotes were detected.The genotype of nd-HPFH including 11 cases of heterozygotes for ^Aγ-225^-222 deletional mutation,and 10 cases of ^Gγ-158C>T heterozygotes.Colusion:1.The level of HbF in nd-HPFH compoundingβ-thalassemia heterozygotes was higher than that in simpleβ-thalassemia heterozygotes,suggesting that nd-HPFH can increase the HbF level ofβ-thalassemia heterozygotes.2.The groups of nd-HPFH compoundingβ⁺-thalassemia heterozygotes andβ⁰-thalassemia heterozygotes had higher MCV and MCH than those in the group of same types of simpleβ-thalassemia heterozygotes.It suggested that nd-HPFH has a significant effect on hematological parameters ofβ-thalassemia heterozygotes.3.The indices of RBC,Hb and HCT were elevated in the group of nd-HPFH compoundingβ-thalassemia homozygotes/double heterozygotes.The results suggested that nd-HPFH can improve the Hb level ofβ-thalassemia homozygotes/double heterozygotes and improve the severity of anemia.4.The Hb level in the group of nd-HPFH compoundingβ⁺/β⁰-orβ⁰/β⁰-thalassemia was elevated.The RBC and HCT in the group of nd-HPFH compoundingβ⁺/β⁰-thalassaemia were higher than those of group with simpleβ⁺/β⁰-thalassaemia group.The results suggested that nd-HPFH has significant effects on Hb level inβ-thalassemia homozygotes/double heterozygotes with different mutations.