Final answer:
A defect in DNA repair genes is associated with hereditary nonpolyposis colon cancer (HNPCC), allowing errors in DNA to accumulate and leading to cancer.
Step-by-step explanation:
A defect in DNA repair genes is associated with an inherited form of colon cancer called hereditary nonpolyposis colon cancer (HNPCC). These repair genes are crucial for correcting DNA mistakes that occur when cells divide. In HNPCC, mutations in these genes allow errors to accumulate, leading to the uncontrolled cell division typical of cancer. Hereditary cancers can arise from germ cell mutations, meaning the defective gene can be passed from parents to offspring. This contrasts with somatic mutations, which can lead to cancer within an individual but are not inherited by children.