TRAFIC (Test for Rare-Variant Association using Family-based Internal Controls) tests for rare variant associations in affected sibpairs by comparing the allele count of rare variants on chromosome regions shared by identical by descent (IBD) to the allele count of rare variants on non-shared chromosome regions. This design is generally robust to population stratification as cases and controls are matched with each sibpair.
For more information about TRAFIC, please see
Lin KH and Zöllner S (2015) Robust and powerful affected sibpair test for rare variant association. Genetic Epidemiology 39:325-333.