1. From the Respiratory Muscle Laboratory, Royal Brompton Hospital, London, United Kingdom (NSH, AHN, and MIP); the Department of Cardiovascular Genetics, Rayne Institute, London, United Kingdom (KIE, JP, EH, and HM); the Respiratory Muscle Laboratory, Guy’s, King’s and St Thomas’ School of Medicine, King’s College Hospital, London, United Kingdom (JM); and the UCL Institute for Human Health and Per