Rg. Elles et al., DIAGNOSIS OF ADULT POLYCYSTIC KIDNEY-DISEASE BY GENETIC-MARKERS AND ULTRASONOGRAPHIC IMAGING IN A VOLUNTARY FAMILY REGISTER, Journal of Medical Genetics, 31(2), 1994, pp. 115-120
Diagnosis of autosomal dominant adult polycystic kidney disease (APKD)
is possible by ultrasonographic scanning (USS) or by using DNA marker
s linked to the PKD1 locus. Ultrasonography is complicated by the age
dependent penetrance of the gene and linkage studies are subject to re
combination errors owing to meiotic crossing over and locus heterogene
ity. This study draws on data collected from a voluntary family regist
er of APKD over 10 years. Records of 150 families were examined, ultra
sound reports were obtained from 242 people at 50% prior risk, and 37
families were typed for DNA markers. The fraction of APKD resulting fr
om loci unlinked to PKD1 (designated PKD2 here) was calculated at 2.94
% (upper confidence limit 8.62%). Some subjects who were negative on i
nitial scan later gave a positive scan, but there was no example of a
definite gene carrier aged over 30 giving a negative scan. In families
large enough for linkage analysis, most people who were at 50% prior
risk could be given a final risk below 5% or above 95%, by using combi
ned ultrasound and DNA studies.