Summary. We describe a sensitive, reliable and reproducible method, based on three multiplex PCR assays, for the rapid detection of seven common a-thalassaemia deletions and one a-globin gene triplication. The new assay detects the a 0 deletions ± ± SEA , ± (a) 20?5 , ± ± MED , ± ± FIL and ± ± THAI in the ®rst multiplex PCR, the second multiplex detects the ±a 3?7 deletion and aaa anti3?7 variant, the third multiplex detects the ±a 4?2 deletion. This simple multiplex method should greatly facilitate the genetic screening and molecular diagnosis of these determinants in populations where athalassaemias are prevalent.

The Factor V Leiden mutation is an important human polymorphism, responsible for increased risk of venous thrombosis in heterozygotes as well as homozygotes. Therefore, screening is a useful possibility, and many detection systems have been described for PCR products. We have developed a simplified and robust assay using oligonucleotide probes for normal and mutant sequences, labeled with europium and samarium, respectively, and measured by time-resolved fluorescence. Populations consisting of 233 Welsh and 148 Irish subjects were examined by both restriction fragment length polymorphism (RFLP) analysis and our assay. The allele frequency was 14/466 in the Welsh and 5/296 in the Irish population, in line with other surveys of European populations. Results were not obtained in 2/381 samples by RFLP, compared with 1/381 with our method. We conclude that our method represents an improved system capable of considerable throughput at reasonable cost.