ABSTRACT
In single gene disorders, family linkage studies are a very powerful means of identifying responsible loci. For complex genetic disorders, such as hypertension, such studies are much less useful. However, modified forms of these types of studies, where the inheritance pattern of alleles is examined within sibling pairs, have more recently been used extensively. Thus, where a large number of affected sibling pairs with hypertension (or any other complex disorder) can be assembled, the inheritance by descent of a particular allele can be examined. Simple genetic principles dictate that siblings share, on average, no more than 50% of a single allele by descent, where the proportion of sharing is significantly increased from this, then the allele is implicated in the inheritance of the phenotype.21
Such studies can utilize either candidate genes, or, importantly, a large number of loci, identified with a genome-wide search to examine multiple genetic markers.
