Indirect DNA analysis was performed on 12 families totalling 80 people. The analysis used five genetic markers flanking the gene: 3'HVR, pGGG, 218 EP6, 24-1, 26-6. In 11 of the families (92%), a linkage with the PKD1 gene in chromosome 16 was established. In one family, the disease did not segregate with the polymorphic markers of PKD1-locus, thus excluding any possibility that a mutation in this locus was the cause of the autosomal dominant polycystic kidney disease (ADPKD). A correlation was discovered between the positive echographic diagnosis and the genotype in the PKD1-dependent patients with ADPKD. In 28.6 percent of the children studied, and in 12.5 percent of subjects under the age of 30, the echographic diagnosis was corrected through DNA analysis.