Table 4.

BRCA1/2 phenocopies occurring after family ascertainment by Manchester score for families with BRCA2 mutations and degree of breast cancer family history criteria

GeneNumber testing negativeMedian age at family ascertainmentProspective breast cancersYears follow-up to June 30, 2011, or censoringBreast cancer rates per 1,000Expected cancersOR (95%CI)
BRCA126236.473,217.82.17
BRCA223835.9142,634.05.3
BRCA1 MS > 1018336.172,401.92.91
BRCA1 MS < 117939.30815.90
BRCA2 MS > 1014937.3111,696.86.48
BRCA2 MS < 118933.03937.03.2
BRCA2 degree of breast cancer family history12535.2101,4486.91.427.04 (3.37–12.95)
BRCA2 no degree of breast cancer family history11235.541,2043.31.572.55 (0.69–6.52)

Abbreviation: MS, Manchester score for BRCA2 in family.