MUTATION ANALYSIS OF THE PKD1 GENE IN PATIENTS WITH ADULT DOMINANT POLYCYSTIC KIDNEY-DISEASE

Autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous disease. Most families show a positive linkage to polymo rphic markers around the PKD1 locus, mapped to 16p13.3. The PKD1 gene has been cloned and encodes polycystin, a protein involved in cell-cel l and cell-extracellular matrix interaction. Most of the 5'-sequence o i PKD1 is reiterated at least three times, with the homologous sequenc es lying on 16p13.1, proximal to PKD1. As a consequence of this duplic ation the analysis of PKD1-mutations on ADPKD1-patients has been limit ed to the 3' non duplicated region. We searched for mutations by singl e strand conformation polymorphism (SSCP) at the PKD1 gene (exons 35 t o 46) on genomic DNA of patients from 24 ADPKD1 families. Cases showin g band shifts were sequenced to define the PKD1-mutation. Pulsed field gel electrophoresis (PFGE) was also performed to determine the presen ce of sed field gel electrophoresis (PFGE) was also performed to deter mine the presence of large deletions. No mutation responsible for the disease in any of the 24 families was found. However, two common polyp morphisms (C72113T and A122736) were found. Both polymorphisms proved to be very useful in linkage analysis in affected families.