cTWAS analysis using summary statistics with "no LD" version

ctwas_sumstats_noLD(
  z_snp,
  weights,
  region_info,
  snp_map,
  z_gene = NULL,
  thin = 1,
  niter_prefit = 3,
  niter = 50,
  init_group_prior = NULL,
  init_group_prior_var = NULL,
  group_prior_var_structure = c("shared_all", "shared_type", "shared_context",
    "shared_nonSNP", "independent"),
  maxSNP = Inf,
  min_var = 2,
  min_gene = 1,
  min_group_size = 100,
  min_nonSNP_PIP = 0.5,
  min_snp_pval = 5e-08,
  min_gene_pval = min_snp_pval,
  min_p_single_effect = 0.8,
  null_method = c("ctwas", "susie", "none"),
  EM_tol = 1e-04,
  coverage = 0.95,
  include_prior = FALSE,
  include_susie_result = FALSE,
  outputdir = NULL,
  outname = "ctwas_noLD",
  ncore = 1,
  seed = 99,
  logfile = NULL,
  verbose = FALSE,
  ...
)

Arguments

z_snp

A data frame with four columns: "id", "A1", "A2", "z". giving the z scores for SNPs. "A1" is effect allele. "A2" is the other allele.

weights

a list of pre-processed prediction weights.

region_info

a data frame of region definitions.

snp_map

a list of data frames with SNP-to-region map for the reference.

z_gene

A data frame with columns: "id", "z", giving the z-scores for genes.

thin

The proportion of SNPs to be used for estimating parameters and screening regions.

niter_prefit

the number of iterations of the E-M algorithm to perform during the initial parameter estimation step.

niter

the maximum number of iterations of the E-M algorithm to perform during the complete parameter estimation step.

init_group_prior

a vector of initial values of prior inclusion probabilities for different groups.

init_group_prior_var

a vector of initial values of prior variances for different groups.

group_prior_var_structure

a string indicating the structure to put on the prior variance parameters. "shared_all" allows all groups to share the same variance parameter. "shared_type" allows all groups in one molecular QTL type to share the same variance parameter. "shared_context" allows all groups in one context (tissue, cell type, condition) to share the same variance parameter. "shared_nonSNP" allows all non-SNP groups to share the same variance parameter. "independent" allows all groups to have their own separate variance parameters. "fixed" sets prior variance parameters to values in init_group_prior_var.

maxSNP

Inf or integer. Maximum number of SNPs in a region. Default is Inf, no limit. This can be useful if there are many SNPs in a region and you don't have enough memory to run the program.

min_var

minimum number of variables (SNPs and genes) in a region when estimating paramters and screening regions.

min_gene

minimum number of genes in a region when estimating paramters and screening regions.

min_group_size

Minimum number of genes in a group. Groups with number of genes < min_group_size will be removed for the analysis.

min_nonSNP_PIP

Regions with non-SNP PIP >= min_nonSNP_PIP will be selected to run finemapping using full SNPs.

min_snp_pval

Select regions with minimum SNP p-values < min_snp_pval.

min_gene_pval

Select regions with minimum gene p-values < min_gene_pval. By default, it is set to the same value as min_snp_pval.

min_p_single_effect

Regions with probability greater than min_p_single_effect of having 1 or fewer effects will be used for parameter estimation.

null_method

Method to compute null model, options: "ctwas", "susie" or "none".

EM_tol

A small, non-negative number specifying the convergence tolerance of log-likelihood for the EM iterations.

coverage

A number between 0 and 1 specifying the “coverage” of the estimated confidence sets.

include_prior

If TRUE, include priors in finemapping results.

include_susie_result

If TRUE, include the "susie" result object in finemapping results.

outputdir

The directory to store output. If specified, save outputs to the directory.

outname

The output name.

ncore

The number of cores used to parallelize susie over regions.

seed

seed for random sampling when thinning the SNPs in region data.

logfile

The log filename. If NULL, print log info on screen.

verbose

If TRUE, print detailed messages.

...

Additional arguments of susie_rss.

Value

a list, including z_gene, estimated parameters, region_data, cross-boundary genes, screening region results, and fine-mapping results.