The simultaneous presence of alpha- and beta-thalassaemia alleles: a pitfall of thalassaemia screening.

OBJECTIVE

To compare the efficacy of routine haematological tests and molecular analysis in the diagnosis of double heterozygous alpha- and beta-thalassaemia.

METHODS

Screening was carried out in extended family members from 125 families registered in the National Thalassaemia Registry, known to have both alpha- and beta-thalassaemia carriers.

RESULTS

Eighty-three individuals from 59 families were identified to be double heterozygous for alpha- and beta-thalassaemia only upon molecular analyses. Among 40 married individuals, 1 was at 25% risk for having beta-thalassaemia major children and 6 for having Bart's hydrops pregnancies.

CONCLUSION

Molecular analysis must be used for the accurate diagnosis of double heterozygous alpha- and beta-thalassaemia for proper risk ascertainment, especially in regions with a high prevalence of both types of thalassaemia.