The team led by Prof. Axenovich has published the manuscript on "Region-Based Association Analysis of Human Quantitative Traits in Related Individuals". Additionally to providing a region-based analysis method, the manuscript also features description of the GRAMMAR+ transformation, which allows treating transformed trait values as if they were measured in a population-based study of unrelated individuals. [click on 'READ MORE' below for complete story]
We foresee this transformation will be very useful, e.g. it allows application of multiple methods developed in the population-based context to the analysis of data with genetic (sub)structure.
The GRAMMAR+ transformation is an improvement of the original GRAMMAR-residuals (aka "environmental residuals"), which are known to lead to conservative analysis. This is not the case with the new GRAMMAR+ transform.
GRAMMAR+ transformation is available in the GenABEL package as one of the objects (...$grresidualY) returned by the 'polygenic' command.