GENETIC-HETEROGENEITY OF POLYCYSTIC KIDNEY-DISEASE IN BULGARIA

Linkage analysis was performed on 22 Bulgarian families with polycysti c kidney disease (PKD) ascertained through the hemodialysis centers of two medical schools, A total of 128 affected and 59 unaffected indivi duals, and 54 spouses have been investigated using eight polymorphic m arkers linked to PKD1 and nine markers to PKD2. The results demonstrat e locus heterogeneity with 0.67 as the maximum likelihood value of alp ha, i,e., the proportion of families linked to PKD1. In five families, the results suggest linkage to PKD2, and observed recombinants place the gene between loci D4S1544 and D4S1542. In one family, two double r ecombinants for closely linked markers on chromosome 16 and on chromos ome 4 give evidence for the lack of linkage to either PKD1 or PKD2, th us suggesting the involvement of a third locus. Analysis of clinical d ata in the PKD1 group versus the unlinked group shows no significant d ifferences in the severity of the disease.