Intermediate phenotypes of childhood obstructive sleep apnea

Area of Science:

• Genetics
• Pediatrics
• Sleep Medicine

Background:

• Intermediate phenotypes bridge genetic predisposition and disease manifestation.
• Identifying heritable intermediate phenotypes aids in understanding disease genetics.
• Childhood obstructive sleep apnea (OSA) has complex genetic underpinnings.

Purpose of the Study:

• To identify intermediate phenotypes for childhood obstructive sleep apnea (OSA).
• To examine traits related to obesity, cardiovascular risk, and upper airway structure.
• To investigate the heritability and genetic associations of these traits with OSA.

Main Methods:

• Recruited 101 families with 127 children and 198 adults.
• Collected anthropometric data, cardiovascular risk factors, and polysomnography.
• Measured lateral parapharyngeal wall (LPW) thickness, cephalometry, and blood pressure.

Main Results:

• Obstructive apnea-hypopnea index (OAHI) heritability was significant in overweight (h²=0.54) but not normal-weight individuals (h²=0.12).
• LPW thickness (h²=0.68) and resting blood pressure (h²=0.36-0.43) were heritable and associated with OAHI.
• These traits showed shared genetic variance with OAHI in overweight children.

Conclusions:

• Lateral parapharyngeal wall thickness and resting blood pressure are potential intermediate phenotypes for OSA, independent of BMI.
• These findings are particularly relevant for overweight children with OSA.
• Further research into the genetics of these phenotypes may elucidate OSA susceptibility.