关键词: 儿童, β珠蛋白变体, 高铁血红蛋白血症, HBB基因, 临床表型

Abstract: A retrospective analysis was conducted on the clinical manifestations, laboratory findings, and genetic test results of a 14-year-old male patient with methemoglobinemia caused by a β-globin variant, who was admitted to Hunan Provincial People's Hospital due to cyanosis appearing at 6 months of age. Hemoglobin electrophoresis revealed an abnormal Hb peak at 3.23 min, accounting for 24.8%. The proband carried a double heterozygous mutation at the HBB gene c.320T>A (inherited from the mother) and c.52A>T (inherited from the father, grandmother, and uncle). A literature review indicated that congenital methemoglobinemia is often caused by defects in the erythrocyte reductase system or structural abnormalities in globin. Cyanosis may persist lifelong even in the absence of cardiopulmonary diseases, and hemoglobin electrophoresis and genetic testing are instrumental in confirming the diagnosis.

Key words: Child, β-globin variant, Methemoglobinemia, HBB gene, Clinical phenotype