Identification of patients with defects in the globin genes.

INTRODUCTION: hemoglobinopathies constitute a major health problem worldwide. These disorders are characterized by a clinical and hematological phenotypic heterogeneity. The increase of HbA2 is an invaluable hematological marker of the beta-thalassemia heterozygosis and of double heterozygosis for the alleles of delta and alpha globin genes or for the alleles of delta and beta globin genes which can cause the increase of HbA2 up to normal or borderline values. CASE REPORT: we report the case of a 30-year-old woman (first pregnant) who was admitted to our Unit at 12 weeks for a screening for thalassemia. The outcomes of the biochemical and haematological exams (MCV, MCH, HbA2, HbF) highlighted that the patient was a carrier of a beta-thalassemic trait. Molecular analysis of the beta globin genes highlighted a β(0)39C>T heterozygous mutation. Biochemical and hematological parameters of the husband (MCV, MCH, HbA2, HbF) were normal except for the level of HbA2 (3,6%). The molecular analysis of the beta globin genes highlighted a IVS2 nt844 C>G heterozygous mutation. Furthermore, the heterozygous mutation δ(+)cod.27G>T was detected in his δ globin gene. For this reason, he was diagnosed a δ+β Thal.
CONCLUSIONS: the aim of this paper is to highlight that biochemical diagnosis could not exhaustive and a molecular diagnostic widening is required to detect the genetic deficiency causing the thalassemic trait.