Detection of the common Hb F Sardinia [A gamma (E19)Ile----Thr] variant by isoelectric focusing in normal newborns and in adults affected by elevated fetal hemoglobin syndromes.

A simple and rapid conventional isoelectric focusing technique for the detection of the silent Hb F Sardinia variant, containing the mutated A gamma T chain, is described. The method is based on thin-layer gels of shallow pH gradient (pH 6.7-7.7) and allows the direct detection of this rather common and widespread Hb variant at a screening level. 15-30 hemolysates from newborns and adults affected by elevated Hb F syndromes, both in the heterozygous and homozygous condition, could be examined simultaneously. The frequency of the A gamma T gene in Sardinian newborn (f = 0.175), in beta 0-thalassemia (f = 0.722), in beta (+)-thalassemia (f = 0.346), and in the non-deletional type of A gamma-HPFH (f = 0), as evaluated with this method, is in accordance with that previously reported by means of other methodologies.