Analysis Of Genetic Factors Of 57 Cases With Hereditary Persistence Of Fetal Hemoglobin In A Tertiary Hospital

Objective:To explore the large fragment deletion of?globin gene cluster,point mutations and polymorphisms sites in the^G?globin gene promoter,single nucleotide polymorphisms?SNP?sites that related to high level fetal hemoglobin?HbF?in fifty-seven cases with hereditary persistence of fetal hemoglobin?HPFH?in a tertiary hospital,and analyze the molecular mechanism that leads to the increase of HbF expression in HPFH.Methods:1.Blood samples of HPFH patients were collected,which were detected by blood routine examination and hemoglobin electrophoresis,healthy examination blood were collected as control group.2.Whole blood genomic DNA was extracted to complete the detection of?-thalassemia,?-thalassemia genes and common deletion-HPFH genotypes.3.The promoter region of ^G?globin gene was amplified to searched the point mutations and polymorphisms sites by Sanger sequencing.4.PCR amplification was performed on eight SNP sites which associated with high level expression of HbF,and genotyping was performed on each sites by Sanger sequencing analysis.5.Analyze the genetic factors lead to the occurrence of HPFH in the tertiary hospital.Results:1.Blood samples from fifth-seven cases with HPFH were collected,the results of thalassemia and common deletion-HPFH genotypes showed as follows:?1?thirty-five cases with normal genotypes;?2?seven cases were diagnosed with?-thalassemia,of which five were-?4.2/???left deficient carriers?,one was--^SEA/???southeast Asian carriers?and one was-?^3.7/--^SEA?deletional HbH disease?;?3?twelve cases were?-thalassemia,including five were CD17/N,one was CD27-28/N,two were CD41-42/N,three were IVS-2-654/N and one was CD26/N;?4?one case was compound?-thalassemia with?-thalassemia?-?4.2/??compound CD41-42/N?;?5?two cases identified with deletion-HPFH compound with?-thalassemia?both were SEA-HPFH/CD17?.2.In the fifty-five cases of nd-HPFH samples,a total of thirty-five cases were CC homozygous for ^G?-158?C?T?,eighteen cases were CT heterozygous for^G?-158?C?T?,and two cases were TT homozygous for^G?-158?C?T?.3.There were statistically significant differences in genotypes distribution of BCL11A rs4671393 and KLF1 rs3817621sites between the group of nd-HPFH and normal?P<0.05?,there were no significant differences in the genotypes distribution of ^G?-158?C?T?,rs4527238,rs28384513,rs9399137,rs2072597,rs117351327,and rs1012855 sites between the group of nd-HPFH and normal?P>0.05?.Conclusion:1.Two cases of SEA-HPFH were found in the detection of deletion HPFH.2.CT heterozygous and TT homozygous for ^G?-158?C?T?were founded,with no other point mutations and polymorphisms sites of^G?globin gene promoter were detected in non-deletion HPFH.3.The gene polymorphisms of BCL11A rs4671393 and KLF1rs3817621 sites were correlated with the high expression of HbF in HPFH,probably was one of the genetic factors in the occurrence of HPFH.