* freq: name of the column storing the minor allele frequence in the gwas file
* pval: name of the column storing the pvalue in the gwas file
* n: name of the column storing the sample size by variants (optional, will be inferred from the MAF, genetic effect and standard deviation if absent)
* ncas: For binary traits, name of the column storing the number of cases by variants (optional)
* ncont: For binary traits, name of the column storing the number of controls by variants (optional)
* z: name of the column storing the genetic effect (beta) in the gwas file
* OR : For binary traits, Odd ratio when available. Not to be confounded with the genetic effect size or 'beta'.
* index-type: precise the type of index
* imputation_quality: (Optional) column containing individual-based imputation quality. Will be used to filter low quality imputation data from GWASs if the option --imputation-quality-treshold is used
