Studies on fetal hemoglobin and gamma globin gene triplication in newborns in Jordan.

Quantitation of fetal hemoglobin (Hb F) and quantitation of it's gamma chain composition is important for the identification of different hemoglobinopathies. This is the first study done on the Jordanian newborns to test the hematological data and the gamma globin chain variants. A total of 52 randomly selected healthy Jordanian newborns were examined. The quantitation of the G gamma and A gamma chains combined with gene mapping using XmnI digestion, were used in the identification of one case of G gamma triplication among the studied samples. A family study of this case showed that adults carrying one copy of this G gamma triplication (13Kb XmnI fragment) had normal levels of HbF (< 1%) and high levels of G gamma (> 80%) while no homozygotes were detected. The remaining 51 newborns had normal frequency values of G gamma and A gamma chains. The frequency of the A gamma T chain among the 52 samples was 0.22. No abnormal alpha or beta chain variants were detected except for one case of HbS.