Pathogenic variants (disease-causing) in the BRCA1 gene can predispose individuals to develop cancer. For women, there is an increased risk of breast and ovarian cancer. For men, there is an increased risk of prostate and male breast cancer. Both sexes may have a higher chance of developing pancreatic cancer. Management of BRCA1–related tumor risk includes regular surveillance tailored to guidelines to detect tumors early as well as risk-reducing options (surgery or medications). Approximately in 1 in 40 individuals of Ashkenazi Jewish ancestry have a pathogenic variant in BRCA1 (and BRCA2) compared to about 1 in 400 people in the general population.
Pathogenic variants in BRCA1 exhibit autosomal dominant inheritance. This means there is a 50% chance the condition can be passed from generation-to-generation. First degree relatives (parents, siblings, children) have a 50% chance to have the same pathogenic variant whereas second degree relatives (grandparents, aunts/uncles, nieces/nephews, half-siblings) have a 25% chance. More distant relatives have lower chances of having the same pathogenic variant when one is identified in the family.
In addition, when an individual inherits pathogenic variants in both copies of the BRCA1 gene, it can cause a rare childhood-onset condition called Fanconi anemia-like disorder. This condition may result in growth failure (smaller than average fetuses or newborns) both in utero and after birth, small heads (microcephaly), intellectual and/or developmental disabilities, atypical coloring of the skin, and possibly minor birth defects impacting the hands and/or feet. This condition deficiency exhibits autosomal recessive inheritance. This means that both parents must have a single pathogenic variant in the BRCA1 gene to have a 25% chance to have a child with the condition.
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Written December 2025
