Finland, located at the edge of the inhabitable world, is one of the best-s
tudied genetic isolates. The characteristic features of population isolates
-founder effect, genetic drift and isolation-have, over the centuries, shap
ed the gene pool of the Finns. Finnish diseases have been a target of exten
sive genetic research and the majority of some 35 disease genes enriched in
this population have been identified; the molecular and cellular consequen
ces of disease mutations are currently being characterized. Special strateg
ies taking advantage of linkage disequilibrium have been efficiently used i
n the initial mapping and restriction of Finnish disease loci and this has
stimulated development of novel statistical approaches in the disease gene
hunt, Identification of mutated genes has provided tools for detailed analy
ses of molecular pathogenesis in Finnish diseases, many of which reveal a d
istinct tissue specificity of clinical phenotype. Often these studies have
not only clarified the molecular detail of Finnish diseases, but also provi
ded novel information on biological processes and metabolic pathways essent
ial for normal development and function of human cells and tissues.