An overrepresentation of HLA-B*07 in the COPD was less significant (Supplemental Table 2) and a likely feature of the interdependence of that allele with HLA-C*07, given that these 2 alleles are in strong linkage disequilibrium (LD) (i.e., an association of alleles at neighboring loci that exceeds purely random cosegregation) (15). Here, HLA-C is linked to chronic obstructive pulmonary disease.