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 dise ase. PKD1 localized to 16p13 is the most common gene, contributing to almos t 85% of all cases, is associated with the most severe form. PKD2, localize d 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 unlin ked to the two most common genetic defects, and therefore little is known a bout 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 mo nths) 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 yea rs, the only clinical finding was hypertension in two. Considerable variati on 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 p rogression. Conclusion. This family exhibits a more aggressive phenotype, in contrast w ith the majority of the described non-PKD1/non-PKD2 families.