Figure 3A.

Clinical risk incorporating genetic risk estimates for major diseases.

Post-test probabilities were calculated by multiplying published pre-test probabilities or disease prevalence (in Caucasian males in the patient's age range, when available; see also Supplemental Table 4) with a series of independent likelihood ratios for each patient allele. Only the 32 diseases with (1) available pre-test probabilities, (2) more than one associated SNP, and (3) with published genotype frequencies are shown here. Disorders such as abdominal aortic aneurysm and progressive supranuclear palsy are not listed here, because they are diseases with only one available SNP. The back of the arrow heads indicate pre-test probabilities, and the point in the direction of the change in probability. Blue lines indicate a lowered post-test probability, and orange indicates an increased post-test probability. The number of independent SNPs used in the calculation of post-test probability for each disease is shown in the right. The advantage of plotting pre and post-test probabilities is illustrated by several cases. For example, While the patient has increased genetic risk for Graves' disease, the pre-test probability of this disease is very low so that post-test probability also remains low. However, while the patient exhibits much less genetic contribution to his risk for prostate cancer, his prior probability is high.