Hematological Characteristics of β-Globin Gene Mutation –50 (G>A) (HBB: c.-100G>A) Carriers in Mainland China

Abstract

The −50 (G>A) (HBB: c.-100G>A) mutation was first reported as a β-thalassemia (β-thal) allele in a Chinese family. However, the hematological features of carriers with this variant are not available. In this study, we present the hematological data associated with −50 (G>A) to determine its phenotype. During a 4-year period, eight simple heterozygotes and three double heterozygotes for the −50 mutation and α-thalassemia (α-thal) were included. The simple heterozygotes had normal hematological parameters. The double heterozygotes had the hematological findings of simple α-thal heterozygotes. Two subjects with a compound heterozygosity for −50 and β-thal were also found, and both had typical hematological parameters of β-thal trait. Therefore, we present evidence that −50 (G>A) is likely a silent β-thal allele. Compound heterozygotes for −50/β-thal had no phenotype of severe β-thal. This information might be helpful in genetic counseling for couples in thalassemia high-prevalence areas.

Keywords:

• β-Thalasssemia (β-thal)
• –50 (G>A) variant
• mean cell volume (MCV)
• silent thalassemia allele

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

This study was supported by the Guangzhou Institute of Pediatrics/Guangzhou Women and Children’s Medical Center, Guangzhou, Guandong Province, People’s Republic of China [IP-2019-004].