Hb Bart's levels in cord blood and alpha-thalassemia mutations in Cyprus

The purpose of this study was to examine the frequency of alpha-thalassemia in the population of Cyprus using cord blood samples. The levels of Hb Bar t's were compared with the hematological indices and the results correlated with the presence of alpha-thalassemia mutations. The protocols for the po lymerase chain reaction detection of the six most common alpha-globin mutat ions encountered in Cyprus were optimized, and the frequency of each mutati on was determined through the screening of 495 random cord blood samples. T he total allele frequency for the mutations examined was 10.6%, of which 1% is due to the triplication of the alpha-globin genes. The -alpha(3.7 kb) d eletion accounts for 72.8% of all detectable mutations, while the - -1MED-I and -(alpha)-20.5 kb mutations account for 7.8%. The level of Hb Bart's an d the MCV and MCH values incord blood samples were found to correlate close ly with the severity of alpha-thalassemia, although the -alpha(3.7 kb) dele tion and perhaps other mild alpha-thalassemia mutations may not give detect able Hb Bart's levels. A reasonably accurate estimate of the alpha-thalasse mia carrier frequency may be obtained from cord blood studies if Bb Bart's estimates are combined with hematological indices. When molecular methods a re added, these give the best way to use cord bloods to survey populations for alpha-thalassemia.