This research study is being conducted to look at oxygen as a treatment of obstructive sleep apnea (OSA) in children with Down syndrome. The main reason for the study is to show how 6 months of oxygen treatment while sleeping affects the participants sleep, quality of life, breathing, heart and if it makes the participant feel better.

The purpose of this research is to compare home sleep apnea testing (HSAT) to in-lab overnight sleep study. We want to see if HSAT in children can be an alternative to in-lab sleep study for the diagnosis of obstructive sleep apnea.

This study seeks to understand why some babies born with a small jaw (micrognathia) have sleep apnea and/or trouble growing and others do not. By enrolling healthy babies, we hope to get a better understanding of how infants breathe during sleep and grow over the first months of life. This observational study involves two study visits that each include an overnight sleep study and some other non-invasive tests.