In 1987 a carrier detection and prenatal diagnostic service for Duchenne muscular dystrophy using molecular technology was instituted at the Department of Human Genetics, University of Cape Town, to serve affe.cted families in southern Africa. DNA samples from 100 affected male subjects and 350 of their relatives from a total of 110 families have been banked. To date restriction fragment length polymorphism (RFLP) analysis and deletion screening has been performed on the DNA of 60 male patients and 116 female relatives at risk of being carriers of the faulty gene. The DNA probes us.ed were pERT 87-1 (Mspl polymorphism) pERT 87-15, pXJ1.1, pXJ2.3 (Taql polymorphism), pXJ1.2 (Ben polymorphism), P20 (Mspl and EeoRV polymorphism) and the cDNA probes. DNA deletions have been detected in 30 of the 60 affected boys and the carrier risks of 49 women have been determined by RFLP analyses. In those families where the risks were uncertain because the affected males had died, prenatal exclusion testing was offered to potential carriers. Two pregnancies were terminated when male fetuses were shown to be affected, since they had the same deletion as that observed in the proband
