摘要目的:探讨单基因病临床意义不明变异（variants of uncertain significance，VUS）实施胚胎植入前遗传学检测（preimplantation genetic testing，PGT）的策略。方法:招募2018年至2020年期间因携带VUS前来中信湘雅生殖与遗传专科医院进行生育咨询的单基因病病例，根据美国医学遗传学与基因组学学会（American College of Medical Genetics and Genomics，ACMG）发布的《ACMG遗传变异分类标准与指南》（以下称ACMG指南）及贝叶斯分析法，对VUS致病性进行重分析，分类为“致病/可能致病变异” “倾向于致病的VUS”“致病性仍不明确的VUS”及“倾向于良性的VUS”。在夫妻双方自主自愿并充分理解风险的原则下，对VUS升级为“致病/可能致病变异”及分类为“倾向于致病的VUS”的家系实施胚胎植入前单基因遗传学检测（preimplantation genetic testing for monogenic disorders，PGT-M）。追踪随访妊娠胎儿、出生孩子的生长发育状况。结果:①16例单基因病家系共检出25个变异，其中1个为致病变异（pathogenic variation，P），3个为可能致病变异（likely pathogenic variation，LP），21个为VUS。重分析后，11个VUS升级为LP（52.4%），7个重分类为“倾向于致病的VUS”（33.3%），2个VUS重分类为“致病性仍不明确的VUS”（9.5%），1个VUS重分类为“倾向于良性的VUS”（4.8%）。②14例单基因病家系进入PGT-M，包括VUS均升级为LP的家系9例，携带1个LP/P及1个“倾向于致病的VUS”家系2例，只携带“倾向于致病的VUS”家系3例。③PGT-M术后出生12个健康婴孩。根据疾病发病年龄随访出生后代，8个子代未表现出与先证者相同的症状，4个子代暂未见疾病症状，因尚未到发病年纪还需要持续随访。结论:针对临床上的VUS，需要按ACMG指南主动寻找新证据并进行重新分析。升级为P/LP的VUS以及升级为倾向于致病的VUS可以在患者知情同意前提下开展PGT-M，为VUS携带者夫妇降低生育单基因病患儿的风险。

abstractsObjective:To explore the strategy of preimplantation genetic testing for monogenic disorders (PGT-M) with variants of uncertain significance (VUS).Methods:Monogenic disorder couples who carried VUS and sought fertility counseling between 2018 and 2020 in Reproductive and Genetic Hospital of CITIC-Xiangya were recruited in this study. The pathogenicity of VUS was reanalyzed according to the Standards and Guidelines for the Interpretation of Sequence Variants released by the American College of Medical Genetics and Genomics (ACMG) and the Bayesian Classification. Those VUSs were reclassified as "pathogenic/likely pathogenic variants (P/LP)", "likely pathogenic VUS", "variants of uncertain significance", or "likely benign VUS". PGT-M was applied to families with VUS upgraded as "P/LP" or "likely pathogenic VUS" under the principle of couples fully voluntary and understanding the risks. We also followed up the developmental status of fetuses and the health condition of the born children.Results:1) A total of 25 variants were detected in 16 families with monogenic disorders, including 1 P, 3 LP, and 21 VUS. After reanalysis, 11 VUS and 7 VUS were upgraded as LP (52.4%) and "likely pathogenic VUS" (33.3%), respectively. Two VUS were still reclassified as "variants of uncertain significance"(9.5%), and 1 VUS was reclassified as "likely benign VUS" (4.8%). 2) PGT-M was implemented for 14 families with monogenic disorders, including 9 families with VUS upgraded as LP, 2 families with one LP/P and one "likely pathogenic VUS", and 3 families with only "likely pathogenic VUS". 3) Twelve healthy babies were born after PGT-M. Following up was done according to the onset age of diseases: 8 offsprings did not show the symptoms as probands, and 4 offsprings had not yet reached the age of onset and need continuous follow-up.Conclusion:It is necessary to actively search for new evidence and reanalyze the pathogenicity of VUS according to ACMG guidelines before PGT-M. Under fully informed consent of the patients, PGT-M can be carried out for VUS reclassified as "P/LP" and "likely pathogenic VUS", to reduce the risk of recurrence.