Genet Med 2004; 6(5): 439-449. “Bayesian analysis for cystic fibrosis risks in prenatal and carrier screening” by Shuji Ogino, Robert B. Wilson, Bert Gold, Pamela Hawley, and Wayne W. Grody.

In table 10 (Scenario 6; page 443-444), the prior probability that the pregnant woman is a carrier with Mutation B should have been 0.5 rather than 0.25. Mutation A was detected in the mother of the affected nephew. The consultant's brother is therefore an obligate carrier of Mutation B, about which we have no other information, since neither the consultant's brother nor the affected nephew has been tested. The conditional probability of a negative test result if the consultant is a carrier with Mutation B is simply the non-detection rate for her ethnicity, or 0.1 (see table below).

Table 1
Full size table