Table 3.

Anticipation effect in families with BRCA1/2 mutations after controlling for ascertainment bias

	Breast Cancer, probands excluded (N=447)				Ovarian Cancer, probands excluded (N=67)
Generation	N	Mean AoO †	Δ AoO (95% CI)	P-value	N	Mean AoO †	Δ AoO (95% CI)	P-value
Grandparents’ gen	81	51.5	10.5 (6.6, 14.3)	<0.001	14	56.9	8.6 (1.7, 15.5)	0.014
Parents’ gen	189	48.0	7.0 (4.2, 9.7)	<0.001	32	52.7	4.4 (−1.0, 9.8)	0.11
Probands’ gen	146	41.0	0 (ref)		19	48.3	0 (ref)
Children’s gen	31	35.0	−6.0 (−10.7, 1.3)	0.013	2	37.9	−10.4 (−24.2, 3.3)	0.14

^†mutation probability-weighted age of onset in years

Abbreviations: Δ AoO, difference in years of age of onset; CI, confidence intervals; gen, generation; ref, reference.