美国梅奥诊所Fergus J. Couch等研究人员合作揭示了BRCA2变异的功能评估与临床分类。2025年1月8日，国际知名学术期刊《自然》在线发表了这一成果。

研究人员分析了从第15到26外显子中所有可能的单核苷酸变异，这些外显子编码BRCA2 DNA结合域的热点区域，用于致病性错义变异的研究。为此，研究人员使用饱和基因组编辑CRISPR-Cas9技术，对人类单倍体HAP1细胞进行内源性靶向敲入。该检测方法相对于无义变异和沉默变异进行了校准，并且使用来自ClinVar的致病和良性标准，以及同源重组修复功能检测结果进行了验证。

根据VarCall贝叶斯模型，共有6959个变异（共6960个评估变异）被分为七类致病性类别。编码功能丧失的错义变异与乳腺癌和卵巢癌的风险增加相关。功能检测结果被整合到ClinGen、美国医学遗传学与基因组学会以及分子病理学协会的临床分类模型中，用于BRCA2变异的临床分类。通过这种方法，91%的变异被分类为致病性或可能致病性，或者为良性或可能良性。这些分类变异可用于改善BRCA2变异个体的临床管理。

据介绍，生殖系BRCA2功能丧失变异可以通过临床遗传检测识别，并且与多种癌症的易感性相关。然而，不确定意义的变异限制了检测结果的临床应用。因此，需要对所有BRCA2变异进行功能表征和临床分类，以促进具有这些变异个体的临床管理。

附：英文原文

Title: Functional evaluation and clinical classification of BRCA2 variants

Author: Huang, Huaizhi, Hu, Chunling, Na, Jie, Hart, Steven N., Gnanaolivu, Rohan David, Abozaid, Mohamed, Rao, Tara, Tecleab, Yohannes A., Pesaran, Tina, Lyra, Paulo Cilas Morais, Karam, Rachid, Yadav, Siddhartha, Nathanson, Katherine L., Domchek, Susan M., de la Hoya, Miguel, Robson, Mark, Mehine, Miika, Bandlamudi, Chaitanya, Mandelker, Diana, Monteiro, Alvaro N. A., Iversen, Edwin S., Boddicker, Nicholas, Chen, Wenan, Richardson, Marcy E., Couch, Fergus J.

Issue&Volume: 2025-01-08

Abstract: Germline BRCA2 loss-of function variants, which can be identified through clinical genetic testing, predispose to several cancers1,2,3,4,5. However, variants of uncertain significance limit the clinical utility of test results. Thus, there is a need for functional characterization and clinical classification of all BRCA2 variants to facilitate the clinical management of individuals with these variants. Here we analysed all possible single-nucleotide variants from exons 15 to 26 that encode the BRCA2 DNA-binding domain hotspot for pathogenic missense variants. To enable this, we used saturation genome editing CRISPR–Cas9-based knock-in endogenous targeting of human haploid HAP1 cells6. The assay was calibrated relative to nonsense and silent variants and was validated using pathogenic and benign standards from ClinVar and results from a homology-directed repair functional assay7. Variants (6,959 out of 6,960 evaluated) were assigned to seven categories of pathogenicity based on a VarCall Bayesian model8. Single-nucleotide variants that encode loss-of-function missense variants were associated with increased risks of breast cancer and ovarian cancer. The functional assay results were integrated into models from ClinGen, the American College of Medical Genetics and Genomics, and the Association for Molecular Pathology9 for clinical classification of BRCA2 variants. Using this approach, 91% were classified as pathogenic or likely pathogenic or as benign or likely benign. These classified variants can be used to improve clinical management of individuals with a BRCA2 variant.

DOI: 10.1038/s41586-024-08388-8

Source: https://www.nature.com/articles/s41586-024-08388-8