To determine the power to detect genetic variants associated with age at onset, we ran analyses using Proc Power in SAS. The analysis was run using minor allele frequencies ranging from 0.05 to 0.50, OR 1.1 to 1.75 and sample size of 45,000. Other factors, such as genetic heterogeneity and gene-environment interaction are likely to affect these estimates. Alpha was adjusted to 5×10−8. For variants with a MAF of 0.15, we would have approximately 80% power to detect effects for OR > 1.23 or < 0.81; for variants with a MAF of 0.3, we would have approximately 80% power to detect effects for OR > 1.18 (or < 0.85).
