Neonatal screening for α-thalassemia by cord hemoglobin Barts: how effective is it?

Int J Lab Hematol. 2015 Oct;37(5):649-53. doi: 10.1111/ijlh.12376. Epub 2015 May 8.

Abstract

Introduction: It has long been recognized that the hemoglobin (Hb) Bart's in cord blood is an accurate indicator of α-thalassemia and that the level of Hb Bart's was increased accordingly with the increasing numbers of the defective α-genes.

Methods: This study used an automatic capillary electrophoresis system to determine the Hb Bart's levels in cord blood. Molecular analyses were used to detect various genotypes of α-thalassemia.

Results: Sixty-nine of the total 1169 newborns were found to have an increased Hb Bart's in cord blood, in whom the diagnosis of α-thalassemia was confirmed by the DNA analysis. The remaining 1100 newborns had no detectable Hb Bart's at birth; among these, 45 carriers of silent α-thalassemia were diagnosed by DNA analysis. All the 45 cases had only the -α(3.7) deletion genotype.

Conclusion: For newborns of one α-gene mutation, especially for 3.7-kb deletion, the method based on Hb Bart's is inadequate and is therefore not reliable for screening.

Keywords: capillary electrophoresis; hemoglobin Bart's; newborns; screening; α-Thalassemia.

MeSH terms

  • Fetal Blood*
  • Genotype
  • Hemoglobins, Abnormal*
  • Humans
  • Infant, Newborn
  • Mutation
  • Neonatal Screening*
  • alpha-Globins / genetics
  • alpha-Globins / metabolism
  • alpha-Thalassemia / blood*
  • alpha-Thalassemia / diagnosis*
  • alpha-Thalassemia / genetics

Substances

  • Hemoglobins, Abnormal
  • alpha-Globins
  • hemoglobin Bart's