[Analysis of five Chinese individuals with rare thalassemia mutation HBB: c.93-21G＞A]

To explore the hematological phenotype and genotypic characteristics of five Chinese individuals with a rare thalassemia mutation HBB: c.93-21G＞A.

A retrospective study was carried out on five individuals identified by the People's Hospital of Yangjiang and Guangzhou Hybribio Co., Ltd. from May 2018 to September 2022. Routine blood test and hemoglobin electrophoresis were performed, and the genotypes of five subjects were determined by using PCR combined with reverse dot blotting (RDB), nested PCR, Gap-PCR and Sanger sequencing. This study was approved by the People's Hospital of Yangjiang (Ethics No. 20240001).

Among the five individuals, hematological data of one was unavailable, and the remaining four had presented with microcytosis and hypochromia. The results of hemoglobin electrophoresis indicated that all of them had a HbA2 level of ≥4.7%. Genetic analysis showed that one case had harbored compound heterozygous mutations of ααα^anti3.7 triplet and HBB: c.93-21G＞A, one had compound heterozygous mutations of -α^3.7 and HBB: c.93-21G＞A, whilst the remaining three were heterozygous for the HBB: c.93-21G＞A mutation.

The hematological phenotype of β-thalassemia carriers (HBB: c.93-21G＞A) is similar to that of other β⁺ thalassemia heterozygotes with mild β-thalassemia characteristics.