Increased prevalence of polycystic kidney disease type 2 among elderly polycystic patients.
Autosomal dominant polycystic kidney disease (ADPKD) is genetically heterogeneous, with at least three chromosomal loci (PKD1, PKD2, and PKD3) accounting for the disease. Mutations in the PKD2 gene, on the long arm of chromosome 4, are estimated to be responsible for 15% of the cases of ADPKD, based on linkage studies. PKD2 is a milder form of the disease, with a mean age of end-stage renal disease (ESRD) approximately 20 years later than PKD1. The object of this study is to determine the proportion of elderly patients with ADPKD with ESRD who harbor mutations in the PKD2 gene. We analyzed all exons and intron-exon boundaries of the PKD2 gene by single-strand conformation polymorphism analysis and silver staining technique in 46 patients with ADPKD who reached ESRD after the age of 63 years or were not yet undergoing renal replacement therapy (RRT) by that age. We performed exactly the same studies in a control group of 40 patients with ADPKD with unknown gene status aged younger than 63 years. In 22 patients, a mutation in the PKD2 gene was defined: 18 of 46 patients from the elderly group and 4 of 40 patients from the control group. We identified 14 different mutations: 4 nonsense mutations, 1 missense mutation, 5 small deletions, 2 insertions, 1 deletion of the whole PKD2 gene, and 1 splicing mutation. Five of these mutations previously were described by our group. Three of the mutations reported in the present study are recurrent. The prevalence of PKD2 disease among elderly patients with ADPKD undergoing RRT is 39.1%, almost three times the prevalence of the disease in the general ADPKD population.
Torra
R
R
Nephrology Department, Renal Transplant Unit, Diagnosis Imaging Center, and Genetics Department, Hospital Clínic, Institut d'Investigations Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Spain. rtorra@clinic.ub.es
Badenas
C
C
Pérez-Oller
L
L
Luis
J
J
Millán
S
S
Nicolau
C
C
Oppenheimer
F
F
Milà
M
M
Darnell
A
A
D000328:Adult; D017668:Age of Onset; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000209:etiology / Q000628:therapy; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D016891:Polycystic Kidney, Autosomal Dominant / Q000150:complications / Q000235:genetics*; D017582:Renal Replacement Therapy; D016019:Survival Analysis; D050396:TRPP Cation Channels
D008565:Membrane Proteins; D050396:TRPP Cation Channels