Leveraging identity-by-descent for disease gene discovery

Genomic regions inherited from a common ancestor are said to be identical-by-descent (IBD). These IBD regions, or segments, can be leveraged to aid in the discovery of disease-associated genetic variation in the absence of large cohorts or pedigrees. In this approach, genetic relatedness is established between affected individuals through the detection of IBD segments. Shared segments that segregate with the disease across individuals can then be prioritized as candidate regions for causal or risk variant discovery, offering a targeted strategy for investigating the genetic basis of diseases. This chapter presents a practical workflow for performing IBD analysis for disease mapping in small-to-medium-sized cohorts using a simulated genomic dataset.