Hb Memphis [HBA2: c.70G>C (or HBA1)] in a Turkish Child: A Case Report and Comparison to Hb Q-Thailand (HBA1: c.223G>C)

Abstract

Hb Memphis [α23(B4)Glu→Gln; HBA2: c.70G > C (or HBA1)] is a stable hemoglobin (Hb) variant caused by a substitution of glutamine for glutamic acid at residue 23 of the α2- or α1-globin chain. Heterozygous Hb Memphis has no known clinical or hematological effect, and all prior reports have resulted from observations in persons of African descent with sickle cell disease and an unusually mild clinical course. Family studies suggest that Hb Memphis may modulate sickling. Only brief characterizations of Hb Memphis trait in the absence of Hb S are present in the current literature. We report isolated Hb Memphis trait in Turkish individuals in whom the initial laboratory incorrectly identified the α variant as Q-Thailand [α74(EF3)Asp→His; HBA1: c.223G > C]. In one case, a heterozygous −3.7 kb α gene deletion was also present, which increased the variant Hb level to a percentage similar to that of the more common Hb Q-Thailand, which may have led to the misidentification. Herein, we discuss the characterization and comparison of these variants and underscore the necessity of confirming characterization by more than one method prior to assigning Hb variant identification.

• α23
• Hb Memphis
• Hb Q-Thailand
• hemoglobin (Hb) variant
• Turkish child