Chunk #20 — Polygenic Risk Scores: A Bridge Between Population Variation and Individual Differences — PRS Practicalities — STEP 4: Calculate PRS for each individual in your sample.
< 5 × 10–8 in the discovery GWAS, generating a person-specific PRS for schizophrenia at each p-value threshold. To limit multiple testing, one could select a p-value threshold that is most predictive of variability of the GWAS phenotype or related phenotype in an independent sample or use permutation based testing to assess whether the overall pattern of associations across p-value thresholds is more than expected by chance within the target dataset (Carey et al., 2016b). PRS can then be used as continuous variables within traditional analytic settings (e.g., regression). Typical covariates in further analyses include factors that confound gene - outcome analyses, such as ancestry differences, age, and sex.
