Rs28997576

rs28997576, aka Cys557Ser or C557S, is a missense variant in the BRCA1 associated RING domain 1 BARD1 gene on chromosome 2.

Researchers suggest that BARD1 Cys557Ser (rs28997576) is an ancient variant that confers risk of single and multiple primary breast cancers, and this risk is amplified in carriers of the BRCA2 999del5 (codon 257, exon 9) mutation. For just the rs28997576(C;G) individuals, the reported odds ratio was 1.82 (CI: 1.11-3.01, p = 0.014), but if the person also carries a rs80359671 or rs80359675 BRCA2 999del5 variant, the odds ratio was reported as 3.11 (CI: 1.16-8.40, p = 0.046). Family history was associated with (slightly) increased risk.

In 300 breast cancer cases in South Americans, rs28997576(C;G) was associated with increased breast cancer risk if, and only if, there was a family history. The odds ratio was 3.4 (CI: 1.2-10, p = 0.04). In families with at least three BC and/or ovarian cancer cases, risk was further increased in the carriers of the rs861539 XRCC3 241Met variant; to a reported odds ratio of 5.01 (CI: 1.36-18.5, p = 0.02).