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. Author manuscript; available in PMC: 2011 May 1.
Published in final edited form as: J Neurolinguistics. 2010 May 1;23(3):176. doi: 10.1016/j.jneuroling.2009.08.003

Figure 1.

Figure 1

Power as a Function of the Difference in Risk for a Disease-related Endophenotype (thought disorder with “schizophrenic” features) in Siblings of Probands with a Disease (schizophrenia) and in the General Population Using Model-free Methods. The generating genetic parameters include both additive and non-additive penetrance values. The near linear relation between power and risk difference holds when the penetrances of both the endophenotype and the disease are not additive and the pleiotropic allele frequency is <0.06. Smaller departures from additivity do not impact power as much. When the allele frequency is high (>0.06), departures from this near linear relation between power and risk difference occur (two circled model-free analysis power values). This graph is based on a sample of 174 asymmetrically ascertained sib pairs. The recombination fraction between marker and disease/endophenotype locus equals 0.01.