Laboratory and clinical features of 28 Duchenne muscular dystrophy patients were evaluated. Positive family history was present in only two cases (7.1%). Dystrophin I-positive fibers were present in 33 percent of the cases with the deletion close to the 5' end of the gene. In the cases with deletion concerning the central part of the gene, all fibers were dystrophin I-negative. In five of the six cases with short stature, the deletion was close to the 5' end of the gene, and short stature was especially seen together with 8th and 13th exon deletion. Statistical analysis concerning the age at which the patient began to have difficulty in standing up and at which he could not walk, did not correlate with the clinical severity and deletion zone, location or extent.