A FAMILY WITH A MILDER FORM OF ADULT DOMINANT POLYCYSTIC KIDNEY-DISEASE NOT LINKED TO THE PKD1 (16P) OR PKD2 (4Q) GENES

Autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous disease. Most families show positive linkage to polymorp hic markers around the PKD1 (16p13.3) or PKD2 (4q21-23) loci. The PKD1 and PKD2 genes have been cloned and mutations defined in a number of patients. Several clinical studies have described a milder phenotype f or PKD2 patients. More recently, evidence for a third genetic locus ha s been found in one Portuguese, one French-Canadian, and one Italian f amily. We identified a Spanish family with negative linkage to the PKD 1 and the PKD2 loci. This family showed a very mild clinical phenotype compared to the other forms of ADPKD, including the non-PKD1/non-PKD2 families previously described.