Participants will attend one study visit, which will include a medical history review, a blood collection, lung function testing, a 6-minute walk test, and a chest computed tomography (CT) scan. A portion of blood will be stored for current and future genetic research. Participants will also complete questionnaires to collect information on activities, health, and quality of life. Some participants will be invited to return for a bronchoscopy, which is a procedure that allows a doctor to sample the inside of the lungs. Study researchers will contact all participants at the end of the study to collect follow-up medical information.