Hb Bart's Levels in Cord Blood and α-Thalassemia Mutations in Cyprus

Abstract

The purpose of this study was to examine the frequency of α-thalassemia in the population of Cyprus using cord blood samples. The levels of Hb Bart's were compared with the hematological indices and the results correlated with the presence of α-thalassemia mutations. The protocols for the polymerase chain reaction detection of the six most common α-globin mutations encountered in Cyprus were optimized, and the frequency of each mutation was determined through the screening of 495 random cord blood samples. The total allele frequency for the mutations examined was 10.6%, of which 1% is due to the triplication of the α-globin genes. The -α(3.7 kb) deletion accounts for 72.8% of all detectable mutations, while the –MED-I and -(α)-20.5 kb mutations account for 7.8%. The level of Hb Bart's and the MCV and MCH values incord blood samples were found to correlate closely with the severity of α-thalassemia, although the -α(3.7 kb) deletion and perhaps other mild α-thalassemia mutations may not give detectable Hb Bart's levels. A reasonably accurate estimate of the α-thalassemia carrier frequency may be obtained from cord blood studies if Hb Bart's estimates are combined with hematological indices. When molecular methods are added, these give the best way to use cord bloods to survey populations for α-thalassemia.