The success of a particular genetic approach depends on the genetic architecture of the disease under investigation- that is, the total number of disease genes and the number and frequency of risk alleles within each gene. For diseases with a relatively simple genetic architecture, in which there is one or a few genes of major effect, linkage analysis (Botstein and Risch, 2003) and homozygosity mapping (Alkuraya, 2010) in families have proven to be highly effective approaches.
