Table 1 Genes whose mutations are reported to cause increased risk of hereditary breast cancers, classified according to the level of risk they confer

Breast cancer risk	Genes
High risk: 10- to 20-fold relative risk	BRCA1 (17q21)
	BRCA2 (13q12.3)
	TP53 (17p13.1)
Intermediate risk: two- to fourfold relative risk	CHEK2 (22q12.1)
	ATM (11q22.3)
	CDH1 (16q22.1)
	PTEN (10q23.31)
	BRIP/FANCJ (17q22)
	PALB2/FANCN (16p12)
Possible low risk: <twofold	FANCA (16q24.3)
Possible low risk: <twofold	FANCE (6p22–p21)