Long-term follow-up of a family with autosomal dominant polycystic kidney disease type 3

Background. Autosomal dominant polycystic kidney disease is one of the most common hereditary diseases in man with an estimated prevalence of 1:1000. At least three genetic loci are responsible for the development of the disease. PKD1 localized to 16p13 is the most common gene, contributing to almost 85% of all cases, is associated with the most severe form. PKD2, localized to 4q21-23, responsible for almost all the remaining cases, is associated with a milder form. Up to now, only five families have been reported unlinked to the two most common genetic defects, and therefore little is known about the clinical findings of the non-PKD1/PKD2 families. Methods. In this report we describe the clinical findings of 18 patients of a non-PKD1/PKD2 family, with a mean follow-up of 52 months (range 3-133 months) in our outpatient clinic. Results. Of the 10 patients older than 40 years, nine were hypertensive; in this age group eight patients exhibited renal failure (two of them were on dialysis) and six had hepatic cysts. In eight patients younger than 40 years, the only clinical finding was hypertension in two. Considerable variation in the rate of progression to renal failure among members of this family was found; on the other hand, some patients did not exhibit any signs of progression. Conclusion. This family exhibits a more aggressive phenotype, in contrast with the majority of the described non-PKD1/non-PKD2 families.