What is the prevalence of Polycstic Kidney Disease in Europe ?
(largest five EU countries: Germany, U.K., France, Italy, Spain)

PKD is very common; the 'autosomal dominant' form (inherited by 50% of
the offspring of anyone that has it) occurs in 1 of 400-2000 live
births.  Not all of these people will become symptomatic, because
different mutations and different 'host factors' allow a broad range
of severity.  genetic testing is available but it is pricey and a long
way from perfect (one gene accounts for about 90% of cases but the
others are tough to test for).
the 'autosomal recessive' form (present in 25% of the offspring born
to two parents that carry the gene) is much less common, affecting
about 1 in 25,000 births.
all of these data hold generally for white populations; it seems to be
much less common in others.

I would reccomend the review article by Patricia Gabow in the New
England Journal of Medicine 1993, v.329 p.332 for a general picture of
the disease; if statistics on frequency are of more interest to you,
check out the article by Levy and Feingold in Kidney International
2000 v. 58 p. 925

hope this helps