Hematological Characteristics Of Beta-Globin Gene Mutation-50 (G > A) (Hbb: C.-100g>A) Carriers In Mainland China

The -50 (G>A) (HBB: c.-100G>A) mutation was first reported as a beta-thalassemia (beta-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 alpha-thalassemia (alpha-thal) were included. The simple heterozygotes had normal hematological parameters. The double heterozygotes had the hematological findings of simple alpha-thal heterozygotes. Two subjects with a compound heterozygosity for -50 and beta-thal were also found, and both had typical hematological parameters of beta-thal trait. Therefore, we present evidence that -50 (G>A) is likely a silent beta-thal allele. Compound heterozygotes for -50/beta-thal had no phenotype of severe beta-thal. This information might be helpful in genetic counseling for couples in thalassemia high-prevalence areas.