Frequency of alpha-thalassemia in Greece.

Using hematological and gene mapping techniques, a cord blood survey was carried out to estimate the frequency of alpha-thalassemia in the Greek population. Out of 227 newborns studied, 16 (7.05%) were found by gene mapping to be alpha-thalassemia 2 heterozygotes (-alpha/alpha alpha), and of these only two had increased levels of hemoglobin Bart's in the cord blood (1.2 and 2.0%). Similarly, one heterozygotes for the common Mediterranean alpha-thalassemia 1 haplotype (-/alpha alpha) and one for the 20.5-kb deletion type (-(alpha)20.5/alpha alpha) were found, showing increased levels of Bart's of 4.8 and 6.6%, respectively. Four (1.76%) heterozygotes for the triple alpha gene arrangement (alpha alpha alpha/alpha alpha) were found. One individual with a level of Bart's in the cord blood of 8% was found to be a double heterozygote for alpha-thalassemia 2 and a dysfunctional alpha gene arrangement (-alpha/-(alpha)?). These results give an overall incidence for alpha-thalassemia in the Greek population of 8.4%.