Background: β-thalassemia is a common inherited hemolytic disorder caused by mutations in the HBB gene. Genetic analysis of 2 new beta-thalassemia patients with deletion mutations in the HBB gene and their family members.
Methods: Their clinical presentation and blood phenotypic tests were analyzed. We detected the approximate degree of deletion of these two new HBB gene deletion mutants and analyzed their specific deletion locations by multiplex ligation-dependent probe amplification (MLPA), reverse breakpoint polymerase chain reaction (GAP-PCR), and sanger DNA sequencing.
Results: Two new deletion mutants of the HBB gene were identified. First, a 49% decrease in the expression of the third exon of the HBB gene was detected by MLPA testing, and then proband 1 and her mother were found to have HBB: exon3del and proband 2 and her mother to have HBB: c.-81A > C by GAP-PCR and sanger sequencing.
Conclusion: When the blood phenotype and clinical manifestations do not match the genotype, the presence of new mutants should be considered, and attention should be paid to further testing to avoid missing the diagnosis, which can help in clinical diagnosis and treatment, prenatal diagnosis and genetic counseling.
Keywords: GAP-PCR; MLPA; rare mutant gene; Β-thalassemia.