[A case with α-thalassemia caused by novel start codon variant in conjunct with right deletion variant of α2-globin gene]

Abstract

Objective: The explore the genetic basis for a patient with microcytic hypochromic anemia and iron deficiency anemia.

Methods: Common deletions and variants of the globin genes were detected by Gap-PCR and next generation sequencing (NGS). Suspected mutations were verified by Sanger sequencing.

Results: Gap-PCR and NGS showed that the proband has carried a αα/-α ^3.7 deletion and a heterozygous c.2T>A (p.Met1Lys) mutation in the initiation codon of the HBA2 gene. The patient and her father both carried α HBA2 c.2T>A(p.Met1Lys) α/-α ^3.7, while her mother and other family members were -α^3.7/-α^3.7 and αα/-α ^3.7, respectively.

Conclusion: Patients with α HBA2 c.2T>A(p.Met1Lys) α/-α ^3.7 genotype have typical features of thalassemia and abnormal hematologic indices compared with those with αα/-α^3.7 genotype, suggesting that the HBA2 c.2T>A (p.Met1Lys) is a pathogenic variant. Above finding has enriched the spectrum of α-thalassemia mutations and enabled genetic counseling and prenatal diagnosis for the family.