[1] EPE, Ctr Hosp Lisboa Norte, Serv Pneumol, Lisbon, Portugal
[2] Inst Nacl Saude, Dept Genet Humana, Lab Proteom, Lisbon, Portugal
[3] Univ Calif San Diego, Div Pulm Crit Care & Sleep Med, La Jolla, CA 92093 USA
[4] Brigham & Womens Hosp, Div Sleep Med, Sleep Disorders Res Program, Boston, MA 02115 USA
[5] Harvard Univ, Sch Med, Boston, MA USA