and others have published power calculations for affected sibling pair linkage based on sample size and λ. Based on Risch’s power calculations (42) assuming 100 ASPs (approximately the number included here) and close linkage, we had sufficient power to detect a locus with a λs = 3. For a λs = 2, power is only about 40%. Our power was somewhat better than this since we had ~2.7 affected members per family.
