Recombination or heterogeneity: is there a second locus for adult polycystic kidney disease?
Twenty-four families with adult onset polycystic kidney disease were typed for markers flanking the PKD1 locus on chromosome 16. The aggregated results gave a significant lod score in favour of linkage to PKD1. Within this group of families two showed unusual features: recombinations, including double recombinations, and, in one family, an unexpectedly high proportion of affected people. We consider the evidence that in these families the disease might result from a mutation at a different locus, PKD2, not linked to PKD1. We suggest that a useful test is to compare the relative numbers of meioses apparently non-recombinant and doubly recombinant for markers flanking the normal disease locus, ignoring meioses recombinant for only a single marker. Using this test, neither our two families nor the data published so far on other families provide compelling evidence for the existence of a second locus for adult polycystic kidney disease. For genetic counselling in families too small to give internal evidence for or against linkage, the extra uncertainty can be handled by using a higher recombination rate.
Elles
R G
RG
Department of Medical Genetics, St Mary's Hospital, Manchester.
Read
A P
AP
Hodgkinson
K A
KA
Watters
A
A
Harris
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D002885:Chromosomes, Human, Pair 16; D005260:Female; D008040:Genetic Linkage; D005819:Genetic Markers; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D007690:Polycystic Kidney Diseases / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic
D005819:Genetic Markers