Hb F-Macedonia-II [G gamma 104(G6)Lys-->Asn]: a new gamma chain variant

In the course of our newborn screening program for the presence of hemoglobinopathies in the Republic of Macedonia, we have detected a new G gamma chain variant with a Lys-->Asn or AAG-->AAC substitution at codon 104. The variant was found in a blood sample from a healthy baby boy of Macedonian nationality. The abnormal chain was quantitated at 32.4% of the total gamma chains by reversed phase high performance liquid chromatography. The characterization of the variant was by sequence analysis of polymerase chain reaction-amplified DNA. The presence of the mutation in the mother was confirmed by Hph I restriction enzyme digestion of the polymerase chain reaction-amplified DNA fragment. Although the mutated G is the last nucleotide of exon 2 and part of the donor splice site sequence of the second intervening sequence of the G gamma gene, it appears that the splicing of the mRNA in this variant is not altered.