The molecular basis of beta-thalassemia in Lebanon: application to prenatal diagnosis.

A study of the molecular lesions of beta-thalassemia in Lebanon revealed the presence of eight different mutations in 25 patients with Cooley's anemia. The IVS1 position 110 mutation predominated with a frequency of 62% and was almost invariably associated with Mediterranean chromosome haplotype I. Five other mutations commonly found in the Mediterranean area occurred with frequencies of 2% to 8%. In addition a G----C substitution in IVS1 position 5 (a lesion previously found in Chinese and Asian Indians) was demonstrated in a patient with Mediterranean haplotype IX. A new mutation at codon 29 was found in two other patients with haplotype II. The characterization of these beta-thalassemia mutations should allow the implementation of a prenatal diagnosis program in that country.