Erratum

In the February 2000 issue of the Journal, in the article “The Relationship between the Sibling Recurrence Risk-Ratio and Genotype Relative Risk,” by Rybicki and Elston (66:593–604) formulas A1 and A2 in the appendix were incorrect. The correct formulas are given below:

and

In addition, a programming error resulted in incorrect values for λ_S under the single-locus dominant model in table 2 and for γ under the single-locus dominant model in table 4. The corrected data for tables 2 and 4 are shown underlined in the tables given here. The corrections were minor and had no effect on the inferences drawn from these results. We thank Sabine Loesgen for pointing out these errors to us.

Table 2.

Comparison of λ_S and λ^*_S, at Different Levels of γ and p

Genetic Model, γ, and pa	λS	λ*Sb	λ* Sc
Single-locus dominant:
γ = 5:
p = .05	1.36	2.28	2.95
p = .20	1.29	1.50	1.79
γ = 20:
p = .05	2.93	3.97	5.51
p = .20	1.64	1.73	2.16

^aEpistatic models are as defined in table 1.

^bProband has at least one susceptibility allele at putative disease locus.

^cProband has both susceptibility alleles at putative disease locus.

Table 4.

Relationship between λ_S, γ, and Allele Sharing at Disease Locus, under Different Genetic Models

Genetic Model, Disease AlleleFrequency, and λ Sa	γ	Proportion ofAlleles Sharedat Disease Locus
Single locus dominant, frequency .01:
λS = 1.5	9.4	.530
λS = 3.0	21.1	.566
λS = 5.0	35.0	.595
λS = 10.0	78.1	.646

^aEpistatic models are as defined in table 1.