孟德尔随机分析求助

各位大神，做TSMR遇到困难，通过read_outcome_data处理outcome是报错如下，请问哪位老师有相关的经验吗？代码如下，不甚感激~

提取暴露SNP

> library(TwoSampleMR)

> exposure<-read.csv(file.choose("exposure_ECD.csv"),header=T)

> exp_clumped<-clump_data(exposure,clump_kb = 10000,clump_r2 = 0.1,clump_p1 = 1,clump_p2 = 1,pop = "EUR")

提取结局SNP

> setwd("D:/！孟德尔随机研究/ECD and CKD/数据处理")

> c<-read.table(file.choose("CKD_EUR_JW_20180223_nstud23.dbgap.txt"),header=T)

> d<-merge(exp_clumped,c,by.x = "SNP",by.y = "RSID")

> write.csv(d,file = "outcome.csv")

> outcome_dat<-read_outcome_data(snps = exp_clumped$SNP,filename = "outcome.csv",sep = ",",snp_col = "SNP",beta_col = "beta",se_col = "se",eaf_col = "eaf",effect_allele_col = "effect_allele",other_allele_col = "other_allele",pval_col = "p")

（问题所在）Error in data.table::fread(filename, header = TRUE, sep = sep) : 文件'outcome.csv' 不存在, 或不可读. getwd()=='D:/！孟德尔随机研究/NAFLD and CKD/数据处理'