Using the polymerase chain reaction (PCR) technique, we have screened the DNA of 42 patients with Duchenne or Becker muscular dystrophy for deletions within the DMD gene. Two regions within putative deletion "hot spots" of this gene were tested, and deletions were found in 16.6% of patients. The oligonucleotide primers employed in this study initiate the amplification of exon sequences and were used to test the suitability and reliability of PCR in deletion screening and prenatal diagnosis using various numbers of cycles and artificial contamination ratios. We compared our approach with both "multiplex DNA amplification" and Southern blot analysis. A comparative evaluation of currently available techniques is presented.