| Objective: To analyze the clinical and hematological features of hemoglobin H(Hb H)disease.Methods: The patients at the First Affiliated Hospital of Guangxi Medical University for diagnosis and treatment of thalassemia from May 2020 to February 2021 were involved.The blood cell count was analyzed by blood cell automatic analyzer.The hemoglobin analysis was performed by high performance liquid chromatography(HPLC).Gap Polymerase Chain Reaction(Gap-PCR)and fluorescence PCR melting curve(FMCA)were used to detect common deletional and non-deletional genotypes of α-thalassemia and β-thalassemia.Next-generation sequencing was used to detect rare mutations.SPSS 22.0 software was used to analyze the obtained data.Results: 1.General information: 77 cases with Hb H disease were detected among 1485 cases.The age ranged from 1 month to 78 years old,in which 23 were children under 14 years old and 54 were adults.There were 41 females and 36 males.2.There were 45 cases of deletional Hb H disease,including 28 cases of--SEA/-α3.7,13 cases of--SEA/-α4.2,3 cases of--SEA/-α27.6 and 1 case of--SEA/-α2.4.Hematological analysis results in the group of deletional Hb H disease were as follow: Hb 57~130.6 g/L,MCV 45~74.6f L,MCH 14.2~23.1pg,MCHC279.7~324g/L.Hemoglobin analysis results in the group were as follow: Hb H 3~23.6% and Hb A2 0.6~2.1 %.3.32 cases of non-deletional Hb H disease were detected,including 26 cases with--SEA/αCSα and 6 cases with--SEA/ αQSα.Hematological analysis results of non-deletional Hb H disease group: Hb 52.7~100g/L,MCV 56.4~82.01 f L,MCH 16~23.9pg,MCHC 237~320g/L。 Hemoglobin analysis results of non-deletional Hb H disease group: Hb H 10~26% and Hb A2 0.3~2.5%。 4.Four rare Hb H disease were found in 77 cases Hb H disease.The genotypes were as follows: Case 1was co-inheritance of-α2.4 deletional mutation and--SEA deletional mutation(--SEA/-α2.4),case 2,case 3 and case 4 were coinheritance of-α27.6 deletional mutation and--SEA deletional mutation(--SEA/-α27.6).Hematological characteristics:Case 1 had no anemia(Hb 120.7g/L),and case 2,case 3,and case 4 had moderate anemia with Hb 77g/L,Hb 76g/L,and Hb 77.3 g/L respectively.MCV and MCH of all 4 cases were lower than normal level.The hemoglobin analysis showed that Hb Bart’s 7% in one case,Hb H in another three cases with 9%,4% and 3% respectively.Conclusion: 1.A total of 6 genotypes causing Hb H disease were found in this study,including--SEA/-α3.7,--SEA/αCSα,--SEA/-α4.2,--SEA/αQSα,--SEA/-α27.6,--SEA/-α2.4.The deletional Hb H disease was more common than non-deletional one,of which--SEA/-α3.7 was the most common type,followed by--SEA/ αCSα type.2.Allele of--SEA is the most common genotype,followed by allele-α3.7,allele αCSα,allele-α4.2 and allele αQSα respectively.3.The MCV,MCH and Hb H in the group of non-deletional Hb H disease were higher than that of deletional Hb H disease,and Hb A2 was lower than that of deletional Hb H disease.The Hb H level of--SEA/-α4.2 was higher than that of--SEA/-α3.7 in the deletional Hb H disease group.The MCV of--SEA/ αCSα is higher than that of--SEA/ αQSα in non-deletional Hb H disease group,but the Hb H level was lower than that of--SEA/ αQSα.4.A rare mutation of Hb H disease with α-globin gene-α27.6 deletional mutation and--SEA deletional mutation was found in Guangxi for the first time,which caused moderate anemia.Hb H or Hb Bart’s were detected for the first time in this type of Hb H disease.The mutation of-α2.4 deletion combined with--SEA deletion caused Hb H disease without anemia,but with lower MCV and MCH.The case had Hb H 9% for Hb analysis.The above two rare deletional mutations cannot be detected by conventional methods and are easy to be miss diagnosed. |
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