Prenatal diagnosis ofI thalassaemia basedon restriction endonuclease analysis ofamplified

SUMMARY IntheMediterranean area,50%ofthe,thalassaemia mutations abolish orcreate a restriction endonuclease site inthe globin gene.Thisstudy describes a new procedure for prenatal detection ofthese,Bthalassaemia defects basedon thedirect visualisation, on an ethidium bromide stained polyacrylamide gel,ofthediscrete DNA fragments produced by restriction endonuclease digestion offetal DNA, enzymatically amplified usingtheDNA polymerase fromthethermophilus bacterium Thermusaquaticus. We applied this procedure to theSardinian population todetect thenonsensemutation atcodon39andtheframeshift atcodon 6ofthe,1globin gene;these arethemostfrequent 13thalassaemia mutations inthis population, accounting for95%and2-2%ofthe,thalassaemia chromosomes. Themainadvantages ofthis procedure aresimplicity (noradioactivity), sensitivity (0-2 Ftg ofDNA),andrapidity (12hours). Theverysmall amountoffetal material required makesamniotic fluid cell culture unnecessary andmay decrease thefetal loss rateassociated withtrophoblast sampling. Bycircumventing the useofradioactive andnon-radioactive probes, thespread ofthis technology tothehighrisk areas willbefacilitated.