1.基于单位点关联分析power

1）在线工具一：gas_power_calculator**

网址：http://csg.sph.umich.edu/abecasis/gas_power_calculator/index.html

软件介绍：

This Genetic Association Study (GAS) Power Calculator is a simple interface that can be used to compute statistical power for large one-stage genetic association studies. The underlying method is derived from the CaTS power calculator for two-stage association studies (2006).

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结果示例：

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2）本地工具：Quanto

网址：http://biostats.usc.edu/Quanto.html

教程：http://blog.sciencenet.cn/blog-3353749-1093073.html

软件介绍：

This program computes sample size or power for association studies of genes, gene-environment interaction, or gene-gene interaction. Available study designs include the matched case-control, case-sibling, case-parent, and case-only designs. Quanto is a 32-bit Windows application requiring Windows 95, 98, NT, 2000, ME, XP, 2003, or Vista to run. The graphical user interface allows the user to easily change the model and view the results without having to edit an input file and rerun the program for every model. The results of a session are stored to a log file. This log can be printed or saved to a file for reviewing at a later date. An option is included to create a text file of the log that can be imported into other documents.

结果示例：

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3）不同类型的统计学样本需求量计算工具：Power and Sample Size**

网址：http://powerandsamplesize.com/

软件介绍：

Free, Online, Easy-to-Use Power and Sample Size Calculators no java applets, plugins, registration, or downloads ... just free Statistical power is a fundamental consideration when designing research experiments. It goes hand-in-hand with sample size. The formulas that our calculators use come from clinical trials, epidemiology, pharmacology, earth sciences, psychology, survey sampling ... basically every scientific discipline.

小结：

方法一为在线工具，简单易于操作，但仅适用于case-control设计；第二种方法需要安装Windows软件，这款软件考虑了单独基因和单独环境效应，以及基因-基因间的互作效应和基因-环境效应，纳入了case-control、同胞对、家系样本等多种设计，适用性更广。

2.基于gene-based关联分析的power计算

用R语言的SKAT包中Power_Logistic(计算power)/ Get_RequiredSampleSize（计算样本量）函数进行分析，该函数功能如下：Compute an average power of SKAT and SKAT-O for testing association between a genomic region and dichotomous phenotypes from case-control studies with a given disease model.匹配流程gene-based关联分析的SKAT 和SKAT-O方法。
几点注意：
1，该方法仅针对gene-based关联分析进行power分析，不可针对单标记的关联分析；
2，在正式分析前进行该分析；
3，用全部标记，而非关联分析检测到的显著变异位点；
4，需要根据具体项目设定发病率、致病位点等位基因频率等参数进行个性化的评估。