Question: Inverse Normal Transformation Of A Quantitative Trait In Gwas
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gravatar for snp_cook12
7.5 years ago by
snp_cook120
United States
snp_cook120 wrote:

hello, I have a question, how do you inverse normally transform a quantitative trait for genetic association studies?

gwas association • 15k views
ADD COMMENTlink modified 3.3 years ago by zju.whw50 • written 7.5 years ago by snp_cook120
2
gravatar for Devon Ryan
7.5 years ago by
Devon Ryan98k
Freiburg, Germany
Devon Ryan98k wrote:

Here's a nice paper on Pubmed Central discussing issues surrounding inverse normal transforms. In general, the idea is to match the normalized rank of the trait to a quantile in a normal distribution. Have a look at equation 1 in the paper I linked to.

ADD COMMENTlink written 7.5 years ago by Devon Ryan98k
2
gravatar for zju.whw
3.3 years ago by
zju.whw50
China
zju.whw50 wrote:

I think the paper mentioned by Devon Ryan worths to read.

To do INT(inverse-normal transformation), you can use the R code below:

qnorm((rank(x,na.last="keep")-0.5)/sum(!is.na(x)))

See the supplement of this paper - Yang et al. Nature 2012.

ADD COMMENTlink written 3.3 years ago by zju.whw50
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