Hematological phenotype analysis of fetuses and patients with hemoglobin H disease / 中华地方病学杂志

ABSTRACT

Objective:To analyze the relationship between hematological and genotype characteristics of fetuses and patients with hemoglobin (Hb) H disease and their natural disease progression.Methods:From 2010 to 2022, a total of 1 252 blood samples from fetuses and patients with Hb H disease who visited the Guangxi Zhuang Autonomous Regional Maternal and Child Health Hospital were collected (including 174 umbilical cord blood samples, 1 062 peripheral blood samples from patients over 2 years old, and 16 peripheral blood samples from patients with rare cases of genotype Hb H). Additionally, 278 peripheral blood samples were collected from patients aged 0 - 2 years old with Hb H 3.7, Hb H 4.2, Hb H CS, and Hb H WS disease for the study of trends in red blood cell development. Multiple probe hybridization and microarray comparative genomic hybridization technology combined with first-generation Sanger sequencing were used for rare mutation detection.Results:Among the 1 062 Hb H disease patients over 2 years old, 62.34% (662/1 062) had gene deletion (--/-α), of which Hb H 3.7 (-- SEA/-α 3.7) and Hb H 4.2 (-- SEA/-α 4.2) were the most common, accounting for 42.28% (449/1 062) and 19.11% (203/1 062) of the total, respectively. Among the non-deletion genotypes (--/αα T or α Tα/αα T), Hb H CS (-- SEA/α CS), Hb H WS (-- SEA/α WS) and α CSα/α CSα accounted for 16.85% (179/1 062), 16.48% (175/1 062) and 1.98% (21/1 062), respectively. The 81.12% (537/662) of patients with deletional Hb H disease showed mild to moderate anemia, with Hb H detection rates ranging from 75% to 80%. Among non-deletional Hb H disease, Hb H WS disease showed the mild (blood Hb concentration > 95 g/L in 90% of patients) phenotype while Hb H CS and Hb H QS (-- SEA/αα QS) patients had moderate to severe anemia, with Hb H detected in peripheral blood at higher levels than in other types of Hb H disease patients. Except for Hb H CS and Hb H QS, which did not show a significant increase in Hb A2 levels when complicated with β-thalassemia, Hb A2 levels were increased (> 3.5%) in all other types of Hb H disease patients. When Hb H disease was complicated with β-thalassemia, Hb H peaks were not detected in either type of Hb H disease. The results of red blood cell development trend detection showed that erythrocyte counts were elevated in patients with Hb H disease compared to their normal counterparts; whereas, blood Hb, mean erythrocyte volume (MCV) and mean erythrocyte hemoglobin content (MCH) were lower than in their normal counterparts ( P < 0.05) and decreased to the minimum at 6 months to 1 year of age. Patients with Hb H CS disease, as the most severe form of anemia, had the highest MCV values ( P < 0.001). The results of fetal cord blood with Hb H disease showed that α CSα/α CSα caused severe intrauterine anemia, followed by Hb H QS and Hb H CS. The content of Hb Bart's in umbilical cord blood was negatively correlated with the severity of anemia ( rs = - 0.58, P < 0.001). When Hb H disease was complicated with β-thalassemia, there was no significant improvement in fetal anemia, and the Hb Bart's content did not change significantly ( P > 0.05). In addition, Hb H 21.9 (-α 21.9kb/-- SEA) and Hb H 2.4 (-α 2.4/-- SEA) were common in patients with deletion rare Hb H. In patients with non-deletion rare Hb H, αα Amsterdam-A1/-- SEA and αα Hb G-Georgia/-- SEA were both first reported. Conclusions:There is heterogeneity in clinical manifestations of patients with different types of Hb H disease or same type of Hb H disease at different developmental stages. When patients with Hb H are complicated with β-thalassemia, the phenotype of patients with the deletion type is improved, while that of patients with the non-deletion type is not. Compared to normal individuals, patients with Hb H disease have lower blood Hb concentration, MCV and MCH, and more rapid physiological changes in red blood cells.