Breast cancer case subjects with pathogenic variants in BRCA1 or BRCA2 had, on average, a younger age at diagnosis than case subjects with pathogenic variants in genes other than BRCA1 or BRCA2 (p = 0.002), with average ages at diagnosis of 38.2 [95% CI: 36.7–39.8] years and 42.4 [95% CI: 40.3–44.6] years, respectively. Here, BRCA1 is linked to breast cancer.