SCOR in Neurobiology of Sleep--Intermediate Traits for Sleep Apnea

BACKGROUND:

Sleep apnea is a common condition that affects 4 percent of middle-aged males and 2 percent of middle-aged females. There is recent evidence that there is a genetic influence because first degree relatives of patients with this disorder have an increased risk of having obstructive sleep apnea. The basis for this increased familial risk is undefined. The investigators postulated that there were three specific intermediate traits, each of which reduced upper airway size, thereby increasing the risk of sleep apnea. These intermediate traits included: a) particular distribution of fat in the neck; b) craniofacial structure; and c) size of critical soft tissues in the airway (soft palate, tongue, lateral pharyngeal walls). All of these risk factors could be assessed quantitatively using advanced magnetic resonance imaging and novel volumetric image analysis techniques that had been developed..

The study was one project within a Specialized Center of Research in Neurobiology of Sleep and Sleep Apnea.

DESIGN NARRATIVE:

The case-control study identified the structural risk factors for sleep apnea. The study was complemented by studies in siblings of the patients and controls in order to identify those traits that demonstrated family aggregation not explained by shared environmental factors. The investigators believed that these structural risk factors would interact to increase the risk of sleep apnea. The elucidation of upper airway structural risk factors should provide the basis for developing new, more effective techniques for screening patients for sleep apnea and provide the basis for performing future DNA analyses aimed at identifying the genetic loci for these risk factors.