BACKGROUND: Apnea of prematurity (AOP) is a disturbance in respiratory rhythm defined by idiopathic pauses in breathing that reduce blood oxygen levels and/or heart rate. It is a major clinical problem among preterm infants.

OBJECTIVES: The primary goal of this study was to estimate the genetic susceptibility to AOP in a cohort of preterm twins. A secondary aim was to identify risk factors associated with AOP in this cohort.

METHODS: A single-center, retrospective study (2000-2008) was performed by using data from 317 premature twin pairs (weeks' gestational age). Heritability estimates were determined by comparing intrapair AOP concordance between 56 monozygotic and 161 dizygotic twin pairs by using structural equation modeling. Risk factors of AOP among a cohort of 543 premature twins were assessed by using mixed-effects logistic regression.

RESULTS: The heritability of AOP was 87% (95% confidence interval [CI]: 0.64-0.97) among same-gender twins. A gender-dependent model revealed that genetic factors accounted for 99% of the variance in male twins (95% CI: 0.89-1.00) and 78% of the variance in female twins (95% CI: 0.49-0.94). Significant risk factors for AOP were low gestational age (P

CONCLUSIONS: These findings suggest that AOP has an important genetic basis underlying this developmental-related disorder of respiratory control. Future genomic studies may provide information on pathophysiological mechanisms that underlie AOP.