THE RELATIVE POWER OF LINKAGE AND ASSOCIATION STUDIES FOR THE DETECTION OF GENES INVOLVED IN HYPERTENSION

Hypertension is a common disorder that shows a polygenic mode of inher itance. Attempts to localize genes involved in the disorder have been carried out using both linkage and association tests. The relative mer it of these two approaches is reviewed with an assessment of their uti lity for detecting genes involved in hypertension. Power calculations were carried out following the method of Risch and Merikangas [1], ass uming markers were typed across the genome. These show that, if there is a single major locus causing susceptibility, non-parametric Linkage strategies using affected sibpairs may well prove very effective. How ever, if there are a number of genes of small effect, the sample size necessary for linkage studies will be prohibitive and a systematic sea rch for allelic association may be more appropriate. This is due to th e dramatic reduction in the excess allele sharing for genes of small e ffect.