About this condition
Sleep Apnea — Genetic Risk
Obstructive sleep apnea (OSA) affects approximately 30 million Americans. Twin studies demonstrate ~40% heritability, with genetic contributions to multiple OSA endotypes: craniofacial anatomy (mandibular size and position), upper airway collapsibility (neuromuscular control), ventilatory control (loop gain — chemoreceptor sensitivity), and arousal threshold.
Craniofacial genes influencing mandibular and midface structure (SMAD2, MSX1 pathway variants) affect upper airway dimensions. Obesity susceptibility genes (FTO, MC4R, LEP) contribute through fat deposition around the upper airway. Ventilatory control genes influence chemoreceptor sensitivity and respiratory drive during sleep. These multi-pathway genetic contributions explain why OSA severity varies independently of BMI.
PHOX2B pathogenic variants cause congenital central hypoventilation syndrome (CCHS) — a rare but life-threatening condition requiring lifelong ventilatory support during sleep. PHOX2B polyalanine expansion repeat length correlates with disease severity. CCHS patients are also at risk for Hirschsprung disease and neuroblastoma, requiring integrated surveillance. PHOX2B testing should be considered in any neonate or infant with unexplained central apnea.
PHOX2B causes congenital central hypoventilation — life-threatening if undiagnosed. Infants with unexplained central apnea need PHOX2B testing urgently. This is a separate condition from obstructive sleep apnea.
- Gene locus
- PHOX2B (4p13), FTO (16q12.2), MC4R (18q21.32), LEP (7q32.1)
