In BRCA1 and BRCA2 LSDBs in which only the proband disease status is provided (e.g., UMD), ascertainment bias must be considered in all assessments as the majority of tested patients are being selected for breast and/or ovarian cancers; thus, truly benign variants may seem to be associated with disease because of this bias. The gene discussed is BRCA1; the disease is ovarian carcinoma.