Family-based penetrance is frequently cited as a major challenge for translating penetrance estimates from familial populations to asymptomatic populations. A systematic review was performed to assess the literature evidencing penetrance estimates in patients without a family history of disease, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Initially 1592 papers were identified, which were filtered to a final nine, through application of inclusion and exclusion criteria. Fundamental differences in the identified papers prevented combination of papers using meta-analysis, so thematic analysis to produce a narrative synthesis was performed. Key themes included disease risk modifiers, evidence, study limitations and bias. A methodological appraisal too was used to assess quality of included studies. It is evident from the findings that the evidence base for penetrance estimates in individuals without a family history of disease is limited. Future work is needed to refine design of penetrance studies and the impact of incorrect estimates.

中文翻译：

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没有家族病史的患者的外显率证据：系统评价。

基于家庭的外显率经常被认为是将外显率估计从家族人群转化为无症状人群的主要挑战。根据系统评价和荟萃分析的首选报告项目（PRISMA）框架，进行了系统评价，以评估证明无家族病史患者外显率估计的文献。最初通过纳入和排除标准筛选出 1592 篇论文，筛选到最后的 9 篇论文。已识别论文的根本差异阻止了使用元分析合并论文，因此进行了主题分析以产生叙述性综合。关键主题包括疾病风险修正因素、证据、研究局限性和偏倚。方法学评估也用于评估纳入研究的质量。从研究结果可以明显看出，对于没有家族病史的个体的外显率估计的证据基础是有限的。未来的工作需要改进外显率研究的设计和不正确估计的影响。