R/harmonise.R
In MRCIEU/TwoSampleMR: Two Sample MR Functions and Interface to MR Base Database
Defines functions
check_required_columns
harmonise
harmonise_11
harmonise_12
harmonise_21
harmonise_22
recode_indels_12
recode_indels_21
recode_indels_22
flip_alleles
check_palindromic
harmonise_make_snp_effects_positive
harmonise_cleanup_variables
harmonise_data
Documented in
harmonise_data
#' Harmonise the alleles and effects between the exposure and outcome
#'
#' In order to perform MR the effect of a SNP on an outcome and exposure must be harmonised to be
#' relative to the same allele.
#'
#' @details
#' Expects data in the format generated by [read_exposure_data()] and [extract_outcome_data()].
#' This means the inputs must be dataframes with the following columns:
#'
#' \code{outcome_dat}:
#' \itemize{
#' \item \code{SNP}
#' \item \code{beta.outcome}
#' \item \code{se.outcome}
#' \item \code{effect_allele.outcome}
#' \item \code{other_allele.outcome}
#' \item \code{eaf.outcome}
#' \item \code{outcome}
#' }
#'
#' \code{exposure_dat}:
#' \itemize{
#' \item \code{SNP}
#' \item \code{beta.exposure}
#' \item \code{se.exposure}
#' \item \code{effect_allele.exposure}
#' \item \code{other_allele.exposure}
#' \item \code{eaf.exposure}
#' }
#'
#' The function tries to harmonise INDELs. If they are coded as sequence strings things work more smoothly.
#' If they are coded as D/I in one dataset it will try to convert them to sequences if the other dataset has adequate information.
#' If coded as D/I in one dataset and as a variant with equal length INDEL alleles in the other, the variant is dropped.
#' If one or both the datasets only has one allele (i.e. the effect allele) then harmonisation is naturally going to be more ambiguous and more variants will be dropped.
#'
#' @param exposure_dat Output from [read_exposure_data()].
#' @param outcome_dat Output from [extract_outcome_data()].
#' @param action Level of strictness in dealing with SNPs.
#' * `action = 1`: Assume all alleles are coded on the forward strand, i.e. do not attempt to flip alleles
#' * `action = 2`: Try to infer positive strand alleles, using allele frequencies for palindromes (default, conservative);
#' * `action = 3`: Correct strand for non-palindromic SNPs, and drop all palindromic SNPs from the analysis (more conservative).
#' If a single value is passed then this action is applied to all outcomes.
#' But multiple values can be supplied as a vector, each element relating to a different outcome.
#'
#' @export
#' @return Data frame with harmonised effects and alleles
harmonise_data <- function(exposure_dat, outcome_dat, action=2)
{
stopifnot(all(action %in% 1:3))
check_required_columns(exposure_dat, "exposure")
check_required_columns(outcome_dat, "outcome")
res.tab <- merge(outcome_dat, exposure_dat, by="SNP")
ncombinations <- length(unique(res.tab$id.outcome))
if(length(action) == 1)
{
action <- rep(action, ncombinations)
} else if(length(action) != ncombinations) {
stop("Action argument must be of length 1 (where the same action will be used for all outcomes), or number of unique id.outcome values (where each outcome will use a different action value)")
}
res.tab <- harmonise_cleanup_variables(res.tab)
if (nrow(res.tab) == 0) {
# NOTE: currently the columns are not in the same order as they would
# be should there be overlapping variants
return(res.tab)
}
d <- data.frame(id.outcome=unique(res.tab$id.outcome), action=action)
res.tab <- merge(res.tab, d, by="id.outcome")
combs <- subset(res.tab, !duplicated(paste(id.exposure, id.outcome)), select=c(id.exposure, id.outcome))
fix.tab <- list()
mr_cols <- c("beta.exposure", "beta.outcome", "se.exposure", "se.outcome")
for(i in 1:nrow(combs))
{
x <- subset(res.tab, id.exposure == combs$id.exposure[i] & id.outcome == combs$id.outcome[i])
message("Harmonising ", x$exposure[1], " (", x$id.exposure[1], ") and ", x$outcome[1], " (", x$id.outcome[1], ")")
x <- harmonise(x, 0.08, x$action[1])
attr(x, "log")[['candidate_variants']] <- sum(exposure_dat$id.exposure == x$id.exposure[1])
attr(x, "log")[['variants_absent_from_reference']] <- sum(exposure_dat$id.exposure == x$id.exposure[1]) - nrow(x)
x$mr_keep[apply(x[, mr_cols], 1, function(y) any(is.na(y)))] <- FALSE
attr(x, "log")[["total_variants"]] <- nrow(x)
attr(x, "log")[["total_variants_for_mr"]] <- sum(x$mr_keep)
attr(x, "log")[["proxy_variants"]] <- ifelse(is.null(x$proxy.outcome), 0, sum(x$proxy.outcome, na.rm=TRUE))
fix.tab[[i]] <- x
}
# fix.tab <- plyr::dlply(res.tab, c("id.exposure", "id.outcome"), function(x)
# {
# x <- plyr::mutate(x)
# message("Harmonising ", x$exposure[1], " (", x$id.exposure[1], ") and ", x$outcome[1], " (", x$id.outcome[1], ")")
# return(x)
# })
jlog <- plyr::rbind.fill(lapply(fix.tab, function(x) attr(x, "log")))
fix.tab <- plyr::rbind.fill(fix.tab)
attr(fix.tab, "log") <- jlog
# fix.tab <- harmonise_make_snp_effects_positive(fix.tab)
if(!"samplesize.outcome" %in% names(fix.tab))
{
fix.tab$samplesize.outcome <- NA
}
return(fix.tab)
}
harmonise_cleanup_variables <- function(res.tab)
{
res.tab$beta.exposure <- as.numeric(res.tab$beta.exposure)
res.tab$beta.outcome <- as.numeric(res.tab$beta.outcome)
res.tab$eaf.exposure <- as.numeric(res.tab$eaf.exposure)
res.tab$eaf.outcome[res.tab$eaf.outcome=="NR"] <- NA
res.tab$eaf.outcome[res.tab$eaf.outcome=="NR "] <- NA
res.tab$eaf.outcome <- as.numeric(res.tab$eaf.outcome)
# convert alleles to upper case
res.tab$effect_allele.exposure <- toupper(res.tab$effect_allele.exposure)
res.tab$other_allele.exposure <- toupper(res.tab$other_allele.exposure)
res.tab$effect_allele.outcome <- toupper(res.tab$effect_allele.outcome)
res.tab$other_allele.outcome <- toupper(res.tab$other_allele.outcome)
res.tab$other_allele.outcome[res.tab$other_allele.outcome == ""] <- NA
return(res.tab)
}
harmonise_make_snp_effects_positive <- function(res.tab)
{
# code SNP effect so that effect allele is the allele that increases the trait
#res.tab[,c("SNP","beta.exposure","beta.outcome","effect_allele.exposure","other_allele.exposure","effect_allele","other_allele","eaf.exposure","eaf.outcome","info_s1","RSQ_s2","RSQ_s3","info_s4","q_p.value")]
pos.change <- which(res.tab$beta.exposure < 0)
res.tab$eaf.exposure[pos.change] <- 1 - res.tab$eaf.exposure[pos.change]
res.tab$beta.exposure[pos.change] <- res.tab$beta.exposure[pos.change] * -1
eff.allele.change <- res.tab$effect_allele.exposure[pos.change]
oth.allele.change <- res.tab$other_allele.exposure[pos.change]
res.tab$effect_allele.exposure[pos.change] <- oth.allele.change
res.tab$other_allele.exposure[pos.change] <- eff.allele.change
return(res.tab)
}
check_palindromic <- function(A1, A2)
{
(A1 == "T" & A2 == "A") |
(A1 == "A" & A2 == "T") |
(A1 == "G" & A2 == "C") |
(A1 == "C" & A2 == "G")
}
flip_alleles <- function(x)
{
x <- toupper(x)
x <- gsub("C", "g", x)
x <- gsub("G", "c", x)
x <- gsub("A", "t", x)
x <- gsub("T", "a", x)
return(toupper(x))
}
recode_indels_22 <- function(A1, A2, B1, B2)
{
ncA1 <- nchar(A1)
ncA2 <- nchar(A2)
ncB1 <- nchar(B1)
ncB2 <- nchar(B2)
i1 <- ncA1 > ncA2 & B1 == "I" & B2 == "D"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
i1 <- ncA1 < ncA2 & B1 == "I" & B2 == "D"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 > ncA2 & B1 == "D" & B2 == "I"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 < ncA2 & B1 == "D" & B2 == "I"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
i1 <- ncB1 > ncB2 & A1 == "I" & A2 == "D"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "I" & A2 == "D"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 > ncB2 & A1 == "D" & A2 == "I"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "D" & A2 == "I"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
keep <- rep(TRUE, length(A1))
keep[(ncA1 > 1 & ncA1 == ncA2 & (B1 == "D" | B1 == "I"))] <- FALSE
keep[(ncB1 > 1 & ncB1 == ncB2 & (A1 == "D" | A1 == "I"))] <- FALSE
keep[A1 == A2] <- FALSE
keep[B1 == B2] <- FALSE
return(data.frame(A1=A1, A2=A2, B1=B1, B2=B2, keep=keep, stringsAsFactors=FALSE))
}
recode_indels_21 <- function(A1, A2, B1)
{
ncA1 <- nchar(A1)
ncA2 <- nchar(A2)
ncB1 <- nchar(B1)
B2 <- rep(NA, length(B1))
i1 <- ncA1 > ncA2 & B1 == "I"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
i1 <- ncA1 < ncA2 & B1 == "I"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 > ncA2 & B1 == "D"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 < ncA2 & B1 == "D"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
keep <- rep(TRUE, length(A1))
keep[A1 == "I" & A2 == "D"] <- FALSE
keep[A1 == "D" & A2 == "I"] <- FALSE
keep[(ncA1 > 1 & ncA1 == ncA2 & (B1 == "D" | B1 == "I"))] <- FALSE
keep[A1 == A2] <- FALSE
return(data.frame(A1=A1, A2=A2, B1=B1, B2=B2, keep=keep, stringsAsFactors=FALSE))
}
recode_indels_12 <- function(A1, B1, B2)
{
ncA1 <- nchar(A1)
ncB1 <- nchar(B1)
ncB2 <- nchar(B2)
A2 <- rep(NA, length(A1))
i1 <- ncB1 > ncB2 & A1 == "I"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "I"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 > ncB2 & A1 == "D"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "D"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
keep <- rep(TRUE, length(A1))
keep[B1 == "I" & B2 == "D"] <- FALSE
keep[B1 == "D" & B2 == "I"] <- FALSE
keep[(ncB1 > 1 & ncB1 == ncB2 & (A1 == "D" | A1 == "I"))] <- FALSE
keep[B1 == B2] <- FALSE
return(data.frame(A1=A1, A2=A2, B1=B1, B2=B2, keep=keep, stringsAsFactors=FALSE))
}
harmonise_22 <- function(SNP, A1, A2, B1, B2, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "2-2"
indel_index <- nchar(A1) > 1 | nchar(A2) > 1 | A1 == "D" | A1 == "I"
temp <- recode_indels_22(A1[indel_index], A2[indel_index], B1[indel_index], B2[indel_index])
A1[indel_index] <- temp$A1
A2[indel_index] <- temp$A2
B1[indel_index] <- temp$B1
B2[indel_index] <- temp$B2
# Find SNPs with alleles that match in A and B
status1 <- (A1 == B1) & (A2 == B2)
to_swap <- (A1 == B2) & (A2 == B1)
jlog[['switched_alleles']] <- sum(to_swap)
# If B's alleles are the wrong way round then swap
Btemp <- B1[to_swap]
B1[to_swap] <- B2[to_swap]
B2[to_swap] <- Btemp
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
# Check again
status1 <- (A1 == B1) & (A2 == B2)
palindromic <- check_palindromic(A1, A2)
# If NOT palindromic and alleles DON'T match then try flipping
i <- !palindromic & !status1
B1[i] <- flip_alleles(B1[i])
B2[i] <- flip_alleles(B2[i])
status1 <- (A1 == B1) & (A2 == B2)
jlog[['flipped_alleles_basic']] <- sum(i)
# If still NOT palindromic and alleles DON'T match then try swapping
i <- !palindromic & !status1
to_swap <- (A1 == B2) & (A2 == B1)
Btemp <- B1[to_swap]
B1[to_swap] <- B2[to_swap]
B2[to_swap] <- Btemp
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
# Any SNPs left with unmatching alleles need to be removed
status1 <- (A1 == B1) & (A2 == B2)
remove <- !status1
remove[indel_index][!temp$keep] <- TRUE
# Now deal with palindromic SNPs
# If the frequency is within tolerance then they are ambiguous and need to be flagged
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
ambiguousA <- tempfA > minf & tempfA < maxf
ambiguousB <- tempfB > minf & tempfB < maxf
# If action = 2 (flip alleles based on frequency) then flip and swap
if(action == 2)
{
status2 <- ((tempfA < 0.5 & tempfB > 0.5) | (tempfA > 0.5 & tempfB < 0.5)) & palindromic
to_swap <- status2 & !remove
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
if(!is.null(jlog))
{
jlog[['flipped_alleles_palindrome']] <- sum(to_swap)
}
} else {
if(!is.null(jlog))
{
jlog[['flipped_alleles_palindrome']] <- 0
}
}
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=(ambiguousA|ambiguousB) & palindromic)
attr(d, "log") <- jlog
return(d)
}
harmonise_21 <- function(SNP, A1, A2, B1, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "2-1"
n <- length(A1)
B2 <- rep(NA, n)
ambiguous <- rep(FALSE, n)
palindromic <- check_palindromic(A1, A2)
remove <- palindromic
indel_index <- nchar(A1) > 1 | nchar(A2) > 1 | A1 == "D" | A1 == "I"
temp <- recode_indels_21(A1[indel_index], A2[indel_index], B1[indel_index])
A1[indel_index] <- temp$A1
A2[indel_index] <- temp$A2
B1[indel_index] <- temp$B1
B2[indel_index] <- temp$B2
remove[indel_index][!temp$keep] <- TRUE
status1 <- A1 == B1
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
freq_similar1 <- (tempfA < minf & tempfB < minf) | (tempfA > maxf & tempfB > maxf)
ambiguous[status1 & !freq_similar1] <- TRUE
B2[status1] <- A2[status1]
to_swap <- A2 == B1
jlog[['switched_alleles']] <- sum(to_swap)
freq_similar2 <- (tempfA < minf & tempfB > maxf) | (tempfA > maxf & tempfB < minf)
ambiguous[to_swap & !freq_similar2] <- TRUE
B2[to_swap] <- B1[to_swap]
B1[to_swap] <- A1[to_swap]
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
to_flip <- A1 != B1 & A2 != B1
jlog[['flipped_alleles_no_oa']] <- sum(to_flip)
ambiguous[to_flip] <- TRUE
B1[to_flip] <- flip_alleles(B1[to_flip])
status1 <- A1 == B1
B2[status1] <- A2[status1]
to_swap <- A2 == B1
B2[to_swap] <- B1[to_swap]
B1[to_swap] <- A1[to_swap]
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=ambiguous | palindromic)
attr(d, "log") <- jlog
return(d)
}
harmonise_12 <- function(SNP, A1, B1, B2, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "1-2"
n <- length(A1)
A2 <- rep(NA, n)
ambiguous <- rep(FALSE, n)
palindromic <- check_palindromic(B1, B2)
remove <- palindromic
indel_index <- nchar(B1) > 1 | nchar(B2) > 1 | B1 == "D" | B1 == "I"
temp <- recode_indels_21(A1[indel_index], B1[indel_index], B2[indel_index])
A1[indel_index] <- temp$A1
A2[indel_index] <- temp$A2
B1[indel_index] <- temp$B1
B2[indel_index] <- temp$B2
remove[indel_index][!temp$keep] <- TRUE
status1 <- A1 == B1
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
freq_similar1 <- (tempfA < minf & tempfB < minf) | (tempfA > maxf & tempfB > maxf)
ambiguous[status1 & !freq_similar1] <- TRUE
A2[status1] <- B2[status1]
to_swap <- A1 == B2
jlog[['switched_alleles']] <- sum(to_swap)
freq_similar2 <- (tempfA < minf & tempfB > maxf) | (tempfA > maxf & tempfB < minf)
ambiguous[to_swap & !freq_similar2] <- TRUE
A2[to_swap] <- A1[to_swap]
A1[to_swap] <- B1[to_swap]
betaA[to_swap] <- betaA[to_swap] * -1
fA[to_swap] <- 1 - fA[to_swap]
to_flip <- A1 != B1 & A1 != B2
jlog[['flipped_alleles_no_oa']] <- sum(to_flip)
ambiguous[to_flip] <- TRUE
A1[to_flip] <- flip_alleles(A1[to_flip])
status1 <- A1 == B1
A2[status1] <- B2[status1]
to_swap <- B2 == A1
B2[to_swap] <- B1[to_swap]
B1[to_swap] <- A1[to_swap]
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=ambiguous | palindromic)
attr(d, "log") <- jlog
return(d)
}
harmonise_11 <- function(SNP, A1, B1, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "1-1"
n <- length(A1)
A2 <- rep(NA, n)
B2 <- rep(NA, n)
ambiguous <- rep(FALSE, n)
palindromic <- FALSE
status1 <- A1 == B1
remove <- !status1
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
freq_similar1 <- (tempfA < minf & tempfB < minf) | (tempfA > maxf & tempfB > maxf)
ambiguous[status1 & !freq_similar1] <- TRUE
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=ambiguous | palindromic)
attr(d, "log") <- jlog
return(d)
}
#' @import data.table
harmonise <- function(dat, tolerance, action)
{
dat$orig_SNP<-dat$SNP
dat <- data.table::data.table(dat)[, SNP_index := 1:.N, by="SNP"]
dat$SNP <- paste0(dat$SNP, "_", dat$SNP_index)
SNP <- dat$SNP
A1 <- dat$effect_allele.exposure
A2 <- dat$other_allele.exposure
B1 <- dat$effect_allele.outcome
B2 <- dat$other_allele.outcome
betaA <- dat$beta.exposure
betaB <- dat$beta.outcome
fA <- dat$eaf.exposure
fB <- dat$eaf.outcome
dat <- subset(dat, select=-c(effect_allele.exposure, other_allele.exposure, effect_allele.outcome, other_allele.outcome, beta.exposure, beta.outcome, eaf.exposure, eaf.outcome))
i22 <- !is.na(A1) & !is.na(A2) & !is.na(B1) & !is.na(B2)
i21 <- !is.na(A1) & !is.na(A2) & !is.na(B1) & is.na(B2)
i12 <- !is.na(A1) & is.na(A2) & !is.na(B1) & !is.na(B2)
i11 <- !is.na(A1) & is.na(A2) & !is.na(B1) & is.na(B2)
d22 <- harmonise_22(SNP[i22], A1[i22], A2[i22], B1[i22], B2[i22], betaA[i22], betaB[i22], fA[i22], fB[i22], tolerance, action)
d21 <- harmonise_21(SNP[i21], A1[i21], A2[i21], B1[i21], betaA[i21], betaB[i21], fA[i21], fB[i21], tolerance, action)
d12 <- harmonise_12(SNP[i12], A1[i12], B1[i12], B2[i12], betaA[i12], betaB[i12], fA[i12], fB[i12], tolerance, action)
d11 <- harmonise_11(SNP[i11], A1[i11], B1[i11], betaA[i11], betaB[i11], fA[i11], fB[i11], tolerance, action)
jlog <- plyr::rbind.fill(
as.data.frame(attr(d22, "log"), stringsAsFactors=FALSE),
as.data.frame(attr(d21, "log"), stringsAsFactors=FALSE),
as.data.frame(attr(d12, "log"), stringsAsFactors=FALSE),
as.data.frame(attr(d11, "log"), stringsAsFactors=FALSE)
)
jlog <- cbind(data.frame(id.exposure=dat$id.exposure[1], id.outcome=dat$id.outcome[1], stringsAsFactors=FALSE), jlog)
d <- rbind(d21, d22, d12, d11)
d <- merge(d, dat, by="SNP", all.x=TRUE)
d$SNP <- d$orig_SNP
d <- subset(d,select=-orig_SNP)
d <- d[order(d$id.outcome), ]
d$mr_keep <- TRUE
if(action == 3)
{
# d1 <- subset(d, !palindromic & !remove & !ambiguous)
d$mr_keep[d$palindromic | d$remove | d$ambiguous] <- FALSE
if(any(d$palindromic))
{
message("Removing the following SNPs for being palindromic:\n", paste(d$SNP[d$palindromic], collapse=", "))
}
if(any(d$remove))
{
message("Removing the following SNPs for incompatible alleles:\n", paste(d$SNP[d$remove], collapse=", "))
}
jlog[['incompatible_alleles']] <- sum(d$remove)
if(any(d$ambiguous & !d$palindromic))
{
message("Removing the following SNPs for having incompatible allele frequencies:\n", paste(d$SNP[d$ambiguous], collapse=", "))
}
jlog[['ambiguous_alleles']] <- sum(d$ambiguous)
}
if(action == 2)
{
# d1 <- subset(d, !remove & !ambiguous)
d$mr_keep[d$remove | d$ambiguous] <- FALSE
if(any(d$remove))
{
message("Removing the following SNPs for incompatible alleles:\n", paste(d$SNP[d$remove], collapse=", "))
}
jlog[['incompatible_alleles']] <- sum(d$remove)
if(any(d$ambiguous))
{
message("Removing the following SNPs for being palindromic with intermediate allele frequencies:\n", paste(d$SNP[d$ambiguous], collapse=", "))
}
jlog[['ambiguous_alleles']] <- sum(d$ambiguous)
}
if(action == 1)
{
# d1 <- subset(d, !remove)
d$mr_keep[d$remove] <- FALSE
if(any(d$remove))
{
message("Removing the following SNPs for incompatible alleles:\n", paste(d$SNP[d$remove], collapse=", "))
}
jlog[['incompatible_alleles']] <- sum(d$remove)
}
# if(nrow(d1) != nrow(d))
# {
# message("Removing the following SNPs due to harmonising issues:\n",
# paste(subset(d, ! SNP %in% d1$SNP)$SNP, collapse="\n")
# )
# }
attr(d, "log") <- jlog
return(d)
}
check_required_columns <- function(dat, type="exposure")
{
required_columns <- c(
"SNP",
paste0(c("id.", "", "beta.", "se.", "effect_allele.", "other_allele."), type)
)
index <- required_columns %in% names(dat)
if(!all(index))
{
stop("The following required columns are missing from ", type, ": ", paste(required_columns[!index], collapse=", "))
}
return(NULL)
}
MRCIEU/TwoSampleMR documentation built on April 22, 2024, 8:42 p.m.
R Package Documentation
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Defines functions check_required_columns harmonise harmonise_11 harmonise_12 harmonise_21 harmonise_22 recode_indels_12 recode_indels_21 recode_indels_22 flip_alleles check_palindromic harmonise_make_snp_effects_positive harmonise_cleanup_variables harmonise_data
Documented in harmonise_data
#' Harmonise the alleles and effects between the exposure and outcome
#'
#' In order to perform MR the effect of a SNP on an outcome and exposure must be harmonised to be
#' relative to the same allele.
#'
#' @details
#' Expects data in the format generated by [read_exposure_data()] and [extract_outcome_data()].
#' This means the inputs must be dataframes with the following columns:
#'
#' \code{outcome_dat}:
#' \itemize{
#' \item \code{SNP}
#' \item \code{beta.outcome}
#' \item \code{se.outcome}
#' \item \code{effect_allele.outcome}
#' \item \code{other_allele.outcome}
#' \item \code{eaf.outcome}
#' \item \code{outcome}
#' }
#'
#' \code{exposure_dat}:
#' \itemize{
#' \item \code{SNP}
#' \item \code{beta.exposure}
#' \item \code{se.exposure}
#' \item \code{effect_allele.exposure}
#' \item \code{other_allele.exposure}
#' \item \code{eaf.exposure}
#' }
#'
#' The function tries to harmonise INDELs. If they are coded as sequence strings things work more smoothly.
#' If they are coded as D/I in one dataset it will try to convert them to sequences if the other dataset has adequate information.
#' If coded as D/I in one dataset and as a variant with equal length INDEL alleles in the other, the variant is dropped.
#' If one or both the datasets only has one allele (i.e. the effect allele) then harmonisation is naturally going to be more ambiguous and more variants will be dropped.
#'
#' @param exposure_dat Output from [read_exposure_data()].
#' @param outcome_dat Output from [extract_outcome_data()].
#' @param action Level of strictness in dealing with SNPs.
#' * `action = 1`: Assume all alleles are coded on the forward strand, i.e. do not attempt to flip alleles
#' * `action = 2`: Try to infer positive strand alleles, using allele frequencies for palindromes (default, conservative);
#' * `action = 3`: Correct strand for non-palindromic SNPs, and drop all palindromic SNPs from the analysis (more conservative).
#' If a single value is passed then this action is applied to all outcomes.
#' But multiple values can be supplied as a vector, each element relating to a different outcome.
#'
#' @export
#' @return Data frame with harmonised effects and alleles
harmonise_data <- function(exposure_dat, outcome_dat, action=2)
{
stopifnot(all(action %in% 1:3))
check_required_columns(exposure_dat, "exposure")
check_required_columns(outcome_dat, "outcome")
res.tab <- merge(outcome_dat, exposure_dat, by="SNP")
ncombinations <- length(unique(res.tab$id.outcome))
if(length(action) == 1)
{
action <- rep(action, ncombinations)
} else if(length(action) != ncombinations) {
stop("Action argument must be of length 1 (where the same action will be used for all outcomes), or number of unique id.outcome values (where each outcome will use a different action value)")
}
res.tab <- harmonise_cleanup_variables(res.tab)
if (nrow(res.tab) == 0) {
# NOTE: currently the columns are not in the same order as they would
# be should there be overlapping variants
return(res.tab)
}
d <- data.frame(id.outcome=unique(res.tab$id.outcome), action=action)
res.tab <- merge(res.tab, d, by="id.outcome")
combs <- subset(res.tab, !duplicated(paste(id.exposure, id.outcome)), select=c(id.exposure, id.outcome))
fix.tab <- list()
mr_cols <- c("beta.exposure", "beta.outcome", "se.exposure", "se.outcome")
for(i in 1:nrow(combs))
{
x <- subset(res.tab, id.exposure == combs$id.exposure[i] & id.outcome == combs$id.outcome[i])
message("Harmonising ", x$exposure[1], " (", x$id.exposure[1], ") and ", x$outcome[1], " (", x$id.outcome[1], ")")
x <- harmonise(x, 0.08, x$action[1])
attr(x, "log")[['candidate_variants']] <- sum(exposure_dat$id.exposure == x$id.exposure[1])
attr(x, "log")[['variants_absent_from_reference']] <- sum(exposure_dat$id.exposure == x$id.exposure[1]) - nrow(x)
x$mr_keep[apply(x[, mr_cols], 1, function(y) any(is.na(y)))] <- FALSE
attr(x, "log")[["total_variants"]] <- nrow(x)
attr(x, "log")[["total_variants_for_mr"]] <- sum(x$mr_keep)
attr(x, "log")[["proxy_variants"]] <- ifelse(is.null(x$proxy.outcome), 0, sum(x$proxy.outcome, na.rm=TRUE))
fix.tab[[i]] <- x
}
# fix.tab <- plyr::dlply(res.tab, c("id.exposure", "id.outcome"), function(x)
# {
# x <- plyr::mutate(x)
# message("Harmonising ", x$exposure[1], " (", x$id.exposure[1], ") and ", x$outcome[1], " (", x$id.outcome[1], ")")
# return(x)
# })
jlog <- plyr::rbind.fill(lapply(fix.tab, function(x) attr(x, "log")))
fix.tab <- plyr::rbind.fill(fix.tab)
attr(fix.tab, "log") <- jlog
# fix.tab <- harmonise_make_snp_effects_positive(fix.tab)
if(!"samplesize.outcome" %in% names(fix.tab))
{
fix.tab$samplesize.outcome <- NA
}
return(fix.tab)
}
harmonise_cleanup_variables <- function(res.tab)
{
res.tab$beta.exposure <- as.numeric(res.tab$beta.exposure)
res.tab$beta.outcome <- as.numeric(res.tab$beta.outcome)
res.tab$eaf.exposure <- as.numeric(res.tab$eaf.exposure)
res.tab$eaf.outcome[res.tab$eaf.outcome=="NR"] <- NA
res.tab$eaf.outcome[res.tab$eaf.outcome=="NR "] <- NA
res.tab$eaf.outcome <- as.numeric(res.tab$eaf.outcome)
# convert alleles to upper case
res.tab$effect_allele.exposure <- toupper(res.tab$effect_allele.exposure)
res.tab$other_allele.exposure <- toupper(res.tab$other_allele.exposure)
res.tab$effect_allele.outcome <- toupper(res.tab$effect_allele.outcome)
res.tab$other_allele.outcome <- toupper(res.tab$other_allele.outcome)
res.tab$other_allele.outcome[res.tab$other_allele.outcome == ""] <- NA
return(res.tab)
}
harmonise_make_snp_effects_positive <- function(res.tab)
{
# code SNP effect so that effect allele is the allele that increases the trait
#res.tab[,c("SNP","beta.exposure","beta.outcome","effect_allele.exposure","other_allele.exposure","effect_allele","other_allele","eaf.exposure","eaf.outcome","info_s1","RSQ_s2","RSQ_s3","info_s4","q_p.value")]
pos.change <- which(res.tab$beta.exposure < 0)
res.tab$eaf.exposure[pos.change] <- 1 - res.tab$eaf.exposure[pos.change]
res.tab$beta.exposure[pos.change] <- res.tab$beta.exposure[pos.change] * -1
eff.allele.change <- res.tab$effect_allele.exposure[pos.change]
oth.allele.change <- res.tab$other_allele.exposure[pos.change]
res.tab$effect_allele.exposure[pos.change] <- oth.allele.change
res.tab$other_allele.exposure[pos.change] <- eff.allele.change
return(res.tab)
}
check_palindromic <- function(A1, A2)
{
(A1 == "T" & A2 == "A") |
(A1 == "A" & A2 == "T") |
(A1 == "G" & A2 == "C") |
(A1 == "C" & A2 == "G")
}
flip_alleles <- function(x)
{
x <- toupper(x)
x <- gsub("C", "g", x)
x <- gsub("G", "c", x)
x <- gsub("A", "t", x)
x <- gsub("T", "a", x)
return(toupper(x))
}
recode_indels_22 <- function(A1, A2, B1, B2)
{
ncA1 <- nchar(A1)
ncA2 <- nchar(A2)
ncB1 <- nchar(B1)
ncB2 <- nchar(B2)
i1 <- ncA1 > ncA2 & B1 == "I" & B2 == "D"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
i1 <- ncA1 < ncA2 & B1 == "I" & B2 == "D"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 > ncA2 & B1 == "D" & B2 == "I"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 < ncA2 & B1 == "D" & B2 == "I"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
i1 <- ncB1 > ncB2 & A1 == "I" & A2 == "D"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "I" & A2 == "D"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 > ncB2 & A1 == "D" & A2 == "I"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "D" & A2 == "I"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
keep <- rep(TRUE, length(A1))
keep[(ncA1 > 1 & ncA1 == ncA2 & (B1 == "D" | B1 == "I"))] <- FALSE
keep[(ncB1 > 1 & ncB1 == ncB2 & (A1 == "D" | A1 == "I"))] <- FALSE
keep[A1 == A2] <- FALSE
keep[B1 == B2] <- FALSE
return(data.frame(A1=A1, A2=A2, B1=B1, B2=B2, keep=keep, stringsAsFactors=FALSE))
}
recode_indels_21 <- function(A1, A2, B1)
{
ncA1 <- nchar(A1)
ncA2 <- nchar(A2)
ncB1 <- nchar(B1)
B2 <- rep(NA, length(B1))
i1 <- ncA1 > ncA2 & B1 == "I"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
i1 <- ncA1 < ncA2 & B1 == "I"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 > ncA2 & B1 == "D"
B1[i1] <- A2[i1]
B2[i1] <- A1[i1]
i1 <- ncA1 < ncA2 & B1 == "D"
B1[i1] <- A1[i1]
B2[i1] <- A2[i1]
keep <- rep(TRUE, length(A1))
keep[A1 == "I" & A2 == "D"] <- FALSE
keep[A1 == "D" & A2 == "I"] <- FALSE
keep[(ncA1 > 1 & ncA1 == ncA2 & (B1 == "D" | B1 == "I"))] <- FALSE
keep[A1 == A2] <- FALSE
return(data.frame(A1=A1, A2=A2, B1=B1, B2=B2, keep=keep, stringsAsFactors=FALSE))
}
recode_indels_12 <- function(A1, B1, B2)
{
ncA1 <- nchar(A1)
ncB1 <- nchar(B1)
ncB2 <- nchar(B2)
A2 <- rep(NA, length(A1))
i1 <- ncB1 > ncB2 & A1 == "I"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "I"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 > ncB2 & A1 == "D"
A2[i1] <- B1[i1]
A1[i1] <- B2[i1]
i1 <- ncB1 < ncB2 & A1 == "D"
A1[i1] <- B1[i1]
A2[i1] <- B2[i1]
keep <- rep(TRUE, length(A1))
keep[B1 == "I" & B2 == "D"] <- FALSE
keep[B1 == "D" & B2 == "I"] <- FALSE
keep[(ncB1 > 1 & ncB1 == ncB2 & (A1 == "D" | A1 == "I"))] <- FALSE
keep[B1 == B2] <- FALSE
return(data.frame(A1=A1, A2=A2, B1=B1, B2=B2, keep=keep, stringsAsFactors=FALSE))
}
harmonise_22 <- function(SNP, A1, A2, B1, B2, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "2-2"
indel_index <- nchar(A1) > 1 | nchar(A2) > 1 | A1 == "D" | A1 == "I"
temp <- recode_indels_22(A1[indel_index], A2[indel_index], B1[indel_index], B2[indel_index])
A1[indel_index] <- temp$A1
A2[indel_index] <- temp$A2
B1[indel_index] <- temp$B1
B2[indel_index] <- temp$B2
# Find SNPs with alleles that match in A and B
status1 <- (A1 == B1) & (A2 == B2)
to_swap <- (A1 == B2) & (A2 == B1)
jlog[['switched_alleles']] <- sum(to_swap)
# If B's alleles are the wrong way round then swap
Btemp <- B1[to_swap]
B1[to_swap] <- B2[to_swap]
B2[to_swap] <- Btemp
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
# Check again
status1 <- (A1 == B1) & (A2 == B2)
palindromic <- check_palindromic(A1, A2)
# If NOT palindromic and alleles DON'T match then try flipping
i <- !palindromic & !status1
B1[i] <- flip_alleles(B1[i])
B2[i] <- flip_alleles(B2[i])
status1 <- (A1 == B1) & (A2 == B2)
jlog[['flipped_alleles_basic']] <- sum(i)
# If still NOT palindromic and alleles DON'T match then try swapping
i <- !palindromic & !status1
to_swap <- (A1 == B2) & (A2 == B1)
Btemp <- B1[to_swap]
B1[to_swap] <- B2[to_swap]
B2[to_swap] <- Btemp
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
# Any SNPs left with unmatching alleles need to be removed
status1 <- (A1 == B1) & (A2 == B2)
remove <- !status1
remove[indel_index][!temp$keep] <- TRUE
# Now deal with palindromic SNPs
# If the frequency is within tolerance then they are ambiguous and need to be flagged
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
ambiguousA <- tempfA > minf & tempfA < maxf
ambiguousB <- tempfB > minf & tempfB < maxf
# If action = 2 (flip alleles based on frequency) then flip and swap
if(action == 2)
{
status2 <- ((tempfA < 0.5 & tempfB > 0.5) | (tempfA > 0.5 & tempfB < 0.5)) & palindromic
to_swap <- status2 & !remove
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
if(!is.null(jlog))
{
jlog[['flipped_alleles_palindrome']] <- sum(to_swap)
}
} else {
if(!is.null(jlog))
{
jlog[['flipped_alleles_palindrome']] <- 0
}
}
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=(ambiguousA|ambiguousB) & palindromic)
attr(d, "log") <- jlog
return(d)
}
harmonise_21 <- function(SNP, A1, A2, B1, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "2-1"
n <- length(A1)
B2 <- rep(NA, n)
ambiguous <- rep(FALSE, n)
palindromic <- check_palindromic(A1, A2)
remove <- palindromic
indel_index <- nchar(A1) > 1 | nchar(A2) > 1 | A1 == "D" | A1 == "I"
temp <- recode_indels_21(A1[indel_index], A2[indel_index], B1[indel_index])
A1[indel_index] <- temp$A1
A2[indel_index] <- temp$A2
B1[indel_index] <- temp$B1
B2[indel_index] <- temp$B2
remove[indel_index][!temp$keep] <- TRUE
status1 <- A1 == B1
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
freq_similar1 <- (tempfA < minf & tempfB < minf) | (tempfA > maxf & tempfB > maxf)
ambiguous[status1 & !freq_similar1] <- TRUE
B2[status1] <- A2[status1]
to_swap <- A2 == B1
jlog[['switched_alleles']] <- sum(to_swap)
freq_similar2 <- (tempfA < minf & tempfB > maxf) | (tempfA > maxf & tempfB < minf)
ambiguous[to_swap & !freq_similar2] <- TRUE
B2[to_swap] <- B1[to_swap]
B1[to_swap] <- A1[to_swap]
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
to_flip <- A1 != B1 & A2 != B1
jlog[['flipped_alleles_no_oa']] <- sum(to_flip)
ambiguous[to_flip] <- TRUE
B1[to_flip] <- flip_alleles(B1[to_flip])
status1 <- A1 == B1
B2[status1] <- A2[status1]
to_swap <- A2 == B1
B2[to_swap] <- B1[to_swap]
B1[to_swap] <- A1[to_swap]
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=ambiguous | palindromic)
attr(d, "log") <- jlog
return(d)
}
harmonise_12 <- function(SNP, A1, B1, B2, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "1-2"
n <- length(A1)
A2 <- rep(NA, n)
ambiguous <- rep(FALSE, n)
palindromic <- check_palindromic(B1, B2)
remove <- palindromic
indel_index <- nchar(B1) > 1 | nchar(B2) > 1 | B1 == "D" | B1 == "I"
temp <- recode_indels_21(A1[indel_index], B1[indel_index], B2[indel_index])
A1[indel_index] <- temp$A1
A2[indel_index] <- temp$A2
B1[indel_index] <- temp$B1
B2[indel_index] <- temp$B2
remove[indel_index][!temp$keep] <- TRUE
status1 <- A1 == B1
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
freq_similar1 <- (tempfA < minf & tempfB < minf) | (tempfA > maxf & tempfB > maxf)
ambiguous[status1 & !freq_similar1] <- TRUE
A2[status1] <- B2[status1]
to_swap <- A1 == B2
jlog[['switched_alleles']] <- sum(to_swap)
freq_similar2 <- (tempfA < minf & tempfB > maxf) | (tempfA > maxf & tempfB < minf)
ambiguous[to_swap & !freq_similar2] <- TRUE
A2[to_swap] <- A1[to_swap]
A1[to_swap] <- B1[to_swap]
betaA[to_swap] <- betaA[to_swap] * -1
fA[to_swap] <- 1 - fA[to_swap]
to_flip <- A1 != B1 & A1 != B2
jlog[['flipped_alleles_no_oa']] <- sum(to_flip)
ambiguous[to_flip] <- TRUE
A1[to_flip] <- flip_alleles(A1[to_flip])
status1 <- A1 == B1
A2[status1] <- B2[status1]
to_swap <- B2 == A1
B2[to_swap] <- B1[to_swap]
B1[to_swap] <- A1[to_swap]
betaB[to_swap] <- betaB[to_swap] * -1
fB[to_swap] <- 1 - fB[to_swap]
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=ambiguous | palindromic)
attr(d, "log") <- jlog
return(d)
}
harmonise_11 <- function(SNP, A1, B1, betaA, betaB, fA, fB, tolerance, action)
{
if(length(SNP) == 0) return(data.frame())
jlog <- list()
jlog[['alleles']] <- "1-1"
n <- length(A1)
A2 <- rep(NA, n)
B2 <- rep(NA, n)
ambiguous <- rep(FALSE, n)
palindromic <- FALSE
status1 <- A1 == B1
remove <- !status1
minf <- 0.5 - tolerance
maxf <- 0.5 + tolerance
tempfA <- fA
tempfB <- fB
tempfA[is.na(tempfA)] <- 0.5
tempfB[is.na(tempfB)] <- 0.5
freq_similar1 <- (tempfA < minf & tempfB < minf) | (tempfA > maxf & tempfB > maxf)
ambiguous[status1 & !freq_similar1] <- TRUE
d <- data.frame(SNP=SNP, effect_allele.exposure=A1, other_allele.exposure=A2, effect_allele.outcome=B1, other_allele.outcome=B2, beta.exposure=betaA, beta.outcome=betaB, eaf.exposure=fA, eaf.outcome=fB, remove=remove, palindromic=palindromic, ambiguous=ambiguous | palindromic)
attr(d, "log") <- jlog
return(d)
}
#' @import data.table
harmonise <- function(dat, tolerance, action)
{
dat$orig_SNP<-dat$SNP
dat <- data.table::data.table(dat)[, SNP_index := 1:.N, by="SNP"]
dat$SNP <- paste0(dat$SNP, "_", dat$SNP_index)
SNP <- dat$SNP
A1 <- dat$effect_allele.exposure
A2 <- dat$other_allele.exposure
B1 <- dat$effect_allele.outcome
B2 <- dat$other_allele.outcome
betaA <- dat$beta.exposure
betaB <- dat$beta.outcome
fA <- dat$eaf.exposure
fB <- dat$eaf.outcome
dat <- subset(dat, select=-c(effect_allele.exposure, other_allele.exposure, effect_allele.outcome, other_allele.outcome, beta.exposure, beta.outcome, eaf.exposure, eaf.outcome))
i22 <- !is.na(A1) & !is.na(A2) & !is.na(B1) & !is.na(B2)
i21 <- !is.na(A1) & !is.na(A2) & !is.na(B1) & is.na(B2)
i12 <- !is.na(A1) & is.na(A2) & !is.na(B1) & !is.na(B2)
i11 <- !is.na(A1) & is.na(A2) & !is.na(B1) & is.na(B2)
d22 <- harmonise_22(SNP[i22], A1[i22], A2[i22], B1[i22], B2[i22], betaA[i22], betaB[i22], fA[i22], fB[i22], tolerance, action)
d21 <- harmonise_21(SNP[i21], A1[i21], A2[i21], B1[i21], betaA[i21], betaB[i21], fA[i21], fB[i21], tolerance, action)
d12 <- harmonise_12(SNP[i12], A1[i12], B1[i12], B2[i12], betaA[i12], betaB[i12], fA[i12], fB[i12], tolerance, action)
d11 <- harmonise_11(SNP[i11], A1[i11], B1[i11], betaA[i11], betaB[i11], fA[i11], fB[i11], tolerance, action)
jlog <- plyr::rbind.fill(
as.data.frame(attr(d22, "log"), stringsAsFactors=FALSE),
as.data.frame(attr(d21, "log"), stringsAsFactors=FALSE),
as.data.frame(attr(d12, "log"), stringsAsFactors=FALSE),
as.data.frame(attr(d11, "log"), stringsAsFactors=FALSE)
)
jlog <- cbind(data.frame(id.exposure=dat$id.exposure[1], id.outcome=dat$id.outcome[1], stringsAsFactors=FALSE), jlog)
d <- rbind(d21, d22, d12, d11)
d <- merge(d, dat, by="SNP", all.x=TRUE)
d$SNP <- d$orig_SNP
d <- subset(d,select=-orig_SNP)
d <- d[order(d$id.outcome), ]
d$mr_keep <- TRUE
if(action == 3)
{
# d1 <- subset(d, !palindromic & !remove & !ambiguous)
d$mr_keep[d$palindromic | d$remove | d$ambiguous] <- FALSE
if(any(d$palindromic))
{
message("Removing the following SNPs for being palindromic:\n", paste(d$SNP[d$palindromic], collapse=", "))
}
if(any(d$remove))
{
message("Removing the following SNPs for incompatible alleles:\n", paste(d$SNP[d$remove], collapse=", "))
}
jlog[['incompatible_alleles']] <- sum(d$remove)
if(any(d$ambiguous & !d$palindromic))
{
message("Removing the following SNPs for having incompatible allele frequencies:\n", paste(d$SNP[d$ambiguous], collapse=", "))
}
jlog[['ambiguous_alleles']] <- sum(d$ambiguous)
}
if(action == 2)
{
# d1 <- subset(d, !remove & !ambiguous)
d$mr_keep[d$remove | d$ambiguous] <- FALSE
if(any(d$remove))
{
message("Removing the following SNPs for incompatible alleles:\n", paste(d$SNP[d$remove], collapse=", "))
}
jlog[['incompatible_alleles']] <- sum(d$remove)
if(any(d$ambiguous))
{
message("Removing the following SNPs for being palindromic with intermediate allele frequencies:\n", paste(d$SNP[d$ambiguous], collapse=", "))
}
jlog[['ambiguous_alleles']] <- sum(d$ambiguous)
}
if(action == 1)
{
# d1 <- subset(d, !remove)
d$mr_keep[d$remove] <- FALSE
if(any(d$remove))
{
message("Removing the following SNPs for incompatible alleles:\n", paste(d$SNP[d$remove], collapse=", "))
}
jlog[['incompatible_alleles']] <- sum(d$remove)
}
# if(nrow(d1) != nrow(d))
# {
# message("Removing the following SNPs due to harmonising issues:\n",
# paste(subset(d, ! SNP %in% d1$SNP)$SNP, collapse="\n")
# )
# }
attr(d, "log") <- jlog
return(d)
}
check_required_columns <- function(dat, type="exposure")
{
required_columns <- c(
"SNP",
paste0(c("id.", "", "beta.", "se.", "effect_allele.", "other_allele."), type)
)
index <- required_columns %in% names(dat)
if(!all(index))
{
stop("The following required columns are missing from ", type, ": ", paste(required_columns[!index], collapse=", "))
}
return(NULL)
}
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