Abstract
Cord blood samples of 3, 232 newborns of different ethnic origins living in the Republic of Macedonia were analyzed by starch gel electrophoresis, polyacrylamide gel electrophoresis and reversed phase high performance liquid chromatography. Hb Bart's was detected in 26 newborns (0.8%) indicating the low incidence of a-thalassemia in the Republic of Macedonia. Five different hemoglobin variants (Hb O-Arab, Hb Hamilton, Hb Strumica, Hb F-Macedonia-I, and Hb F-Macedonia-ll) were also detected. The levels of the Gγ chains fell into three categories; normal range with Gγ between 50 and 80% (3, 143 newborns or 97.2%), low range with Gγ levels of <50% (35 new-boms or 1.1%), and high range with Gγ levels of >80% (54 newborns or 1.7%). The overall incidence of the AγT variant was 20.8%, similar to that found in several Mediterranean populations. DNA analyses showed that the molecular basis of high and low Gγ determinants are heterogeneous in our population. γ-Gene triplications and the GγGγ arrangements were detected in newborns with high Gγ levels, while γ gene deletions and AγAγ arrangements were found in newborns with low Gγ levels. All but one of the 135 samples with Gγ between 50 and 80% had the normal GγAγ arrangement on both chromosomes; the only exception was an Albanian newborn (Gγ = 63%) with an -A/γGγGγAγ arrangement.