Fig. 1From: X chromosome associations with chronic obstructive pulmonary disease and related phenotypes: an X chromosome-wide association studyCleaning and imputation by study. Steps in subject cleaning, variant cleaning, and imputation prior to X chromosome association analysis. Numbers in parentheses represent subjects or variants removed. Abbreviations:Â Chr chromosome, SNP single nucleotide polymorphism, MAF minor allele frequency, QC quality controlBack to article page