ELN and chronic obstructive pulmonary disease: In addition to the well-documented role of alpha-1 antitrypsin as a rare genetic risk factor for COPD, we have recently described a rare functional mutation in the terminal exon of the elastin gene that segregates with disease status in a family of severe early-onset COPD and was observed in 1.25% of subjects participating in the NETT Genetics Ancillary Study as compared to 0.55% in the NAS cohort[37].