Genetic research and clinical analysis of deletional Chinese ^Gγ⁺(^Aγδβ)⁰ -thalassemia and Southeast Asian HPFH in South China

Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia and SEA-HPFH are the most common types of β-globin gene cluster deletion in Chinese population. The aim of the study was to analyze clinical features of deletional Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia and Southeast Asian hereditary persistence of fetal hemoglobin (SEA-HPFH) in South China. A total of 930 subjects with fetal hemoglobin (HbF) level ≥ 2% were selected on genetic research of Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia and SEA-HPFH. The gap polymerase chain reaction was performed to identify the deletions. One hundred cases of Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia were detected, including 90 cases of Chinese ^Gγ⁺(^Aγδβ)⁰/β^N-thalassemia, 7 cases of Chinese ^Gγ⁺(^Aγδβ)⁰ /β^N-thalassemia combined with α-thalassemia, 2 cases of Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia combined with β-thalassemia, and 1 case of Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia combined with β-gene mutation. One hundred nine cases of SEA-HPFH were detected, including 97 cases of SEA-HPFH/β^N, 9 cases of SEA-HPFH/β^N combined with α-thalassemia, 2 cases of SEA-HPFH combined with β-thalassemia, and 1 case of SEA-HPFH combined with β-gene mutation. Statistical analysis indicates significant differences in MCV (mean corpuscular volume), MCH (mean corpuscular hemoglobin), and HbA2 and HbF levels between Chinese ^Gγ⁺(^Aγδβ)⁰-thalassemia heterozygotes and SEA-HPFH heterozygotes (P < 0.001). There are statistical differences in hematological parameters between them. Clinical phenotypic analysis can provide guidance for genetic counseling and prenatal diagnosis.