A Woman with Missing Hb A2 Due to a Novel (εγ)δβ0-Thalassemia and a Novel δ-Globin Variant Hb A2-Gebenstorf (HBD: c.209G>A)

Hemoglobin. 2020 May;44(3):214-217. doi: 10.1080/03630269.2020.1779739. Epub 2020 Jul 1.

Abstract

A woman completely lacking Hb A2 on the high performance liquid chromatography (HPLC) analysis, presented with a novel deletional (εγ)δβ0-thal and a δ-globin gene variant. This combination causes a β-thalassemia (β-thal) minor phenotype. The woman was referred by a hematologist due to abnormal blood counts. Multiplex ligation-dependent probe amplification (MLPA) and microarray analysis showed a heterozygous, 177 kb long deletion that removed the locus control region enhancer plus the ε, Gγ and Aγ genes. Additional sequencing revealed a novel variant HBD: c.209G>A, p.Gly70Asp in the heterozygous state, called Hb A2-Gebenstorf. The combination of the two variants explains the lack of Hb A2 in this woman.

Keywords: Lack of Hb A2; novel locus control region (LCR) enhancer deletion; novel δ gene variant Hb A2-Gebenstorf; β-thalassemia (β-thal).

Publication types

  • Case Reports

MeSH terms

  • Alleles
  • Chromatography, High Pressure Liquid
  • DNA Mutational Analysis
  • Erythrocyte Indices
  • Female
  • Genetic Association Studies / methods
  • Genetic Predisposition to Disease
  • Genetic Testing
  • Hemoglobin A2 / genetics*
  • Heterozygote
  • Humans
  • Mutation*
  • Phenotype
  • beta-Thalassemia / blood
  • beta-Thalassemia / diagnosis*
  • beta-Thalassemia / genetics*
  • delta-Globins / genetics*

Substances

  • delta-Globins
  • Hemoglobin A2