Use of DNA markers in diagnosis of Adult Dominant Polycystic Kidney Disease

Gene mapping permits the prenatal and/or presymptomatic detection of genetic diseases with a late clinical onset as in Huntington chorea and in Adult Dominant Polycystic kidney disease (ADPKD). In ADPKD, a large number of DNA markers, closely linked to PKD1, on the short arm of chromosome 16, have been detected. During the first decades of life, the use of DNA markers permits an early diagnosis of ADPKD, with a specificity of 97%, much greater than the specificity of sonography. However, an estimated 3-5 % of families suffering from ADPKD have shown no evidence of linkage to PKD1. This heterogeneity allows this type of analysis only in large families, with one or more affected members, in each generation, in whom it is possible to demonstrate the linkage with DNA markers on chromosome 16. We report the results of a biological and molecular study carried out an 12 families, with a total of 120 individuals, in which ADPKD segregates. A restriction fragment length polymorphism (RFLP's) analysis was performed. Two families shoed a genetic heterogeneity even if not phenotypically different from the other ones.