Molecular spectrum of alpha-thalassemia in jordan

Abstract EN

Objective: The aim of this study was to define the spectrum of ?-thalassemia determinants existing in Jordan.

Methods: A total 286 suspected ?-thalassemia subjects including 29 hemoglobin Hb (Hb H) patients were examined by polymerase chain reaction and restriction enzyme digestion.

Polymerase chain reaction product was examined by agarose gel electrophoresis.

Results: Five different ?-thalassemia determinants were characterized in 336 chromosomes.

The most prevalent ?-thalassemia determinant was the single gene deletion -?3.7 (45%).

The non-gene deletion ?5nt accounted for 27% of thalassemic chromosomes, followed by the non-gene deletional determinant ?T-Saudi (23%).

The two-gene deletional determinant --MED was characterized only in 4% of thalassemic chromosomes.

Triplicated ?-gene determinant was observed in two heterozygous individuals (???/??).

Four different genotypes were found to be responsible for Hb H disease.

Homozygosity for the non-deletional determinant ? T-Saudi (? T-Saudi?/? T-Saudi?) was observed in the majority of those patients (76%) and was found to be associated with high Hb H levels.

Less commonly, Hb H disease occurred as a result of compound hterozygosity between --MED determinant with other determinants; (--MED / ?T-Saudi?), (--MED / ?5nt ? ), (--MED / - ?3.7 ?).

Conclusion: The outcome of this pilot study provides valuable and basic information about the spectrum of ?-thalassemia mutations in Jordan that might be useful in setting a strategy for molecular diagnosis of ?- thalassemia carrier status and Hb H disease in this country.