Sibling association test (SIBASSOC)
The dataset consists of one affected sibling from each sibship
which is compared with an unaffected sibling chosen
on the basis of having a maximally
different marker genotype.
In the first sibship, the case is AC and the control is BD. In the second, the case is AA and the control is BC.
The method tests whether certain alleles are found more often among
cases than their controls.
Results from multiallelic markers can be analysed in a similar way as for ETDT and data can be combined
with families for which parents are available.
The method uses only one affected and one unaffected subject from each
sibship, but is more powerful than a test based only on randomly chosen
pairs of affected and unaffected sibs.
It is a test for association as well as
linkage even when applied to sibships.
