Researchers at the University of Massachusetts (UMass) Medical School, Worcester, Mass, have found that heredity may play a strong role in determining an infant’s susceptibility to apnea of prematurity (AOP), a potentially life-threatening condition characterized by pauses in breathing that can last for more than 20 seconds. The findings, published in the journal Pediatrics, could lead to the development of more effective treatments and screening methods for AOP, which affects more than 50% of premature infants and is almost universal in the smallest of preemies.

Because it causes gaps in breathing, AOP can lead to reduced oxygen levels and slowed heart rate in premature infants, as well as permanent disabilities and long-term damage to internal organs. Infants with AOP require around-the-clock monitoring and often must be gently jostled or rubbed to encourage inhalation and continued breathing. Such activities, however, wake the baby, depriving it of much needed sleep. In severe cases, pharmaceutical interventions, such as caffeine, may be required. While the permanent consequences of AOP and its treatments have yet to be fully studied, infants with AOP are more likely to have cognitive and behavior problems, and other long-term disabilities.

To understand why there is so much variability in the incidence and severity of apnea in premature infants and why some infants outgrow the problem sooner than others, the researchers compared the rates of AOP in 217 identical and fraternal twin pairs to determine whether heredity played a role in the condition. Using advanced statistical models, they calculated the correlation of the onset of AOP in twins born before 26 weeks gestational age to determine if a genetic component was responsible.

The researchers discovered that in same-gender twin cases where one fraternal twin suffered from AOP, the other twin had a 62% likelihood of also having AOP. In identical twins, the correlation of AOP diagnosis was significantly higher—87%. According to the researchers, these findings indicate that genetic influences shared by identical twins play a significant part in developing AOP.

“While other factors, including environmental ones, contribute to AOP, our study suggests a surprisingly strong genetic predisposition for AOP,” said David Paydarfar, MD, professor of neurology and physiology at the UMass Medical School. “Further research is needed to confirm our results and to find the specific gene or group of genes that are linked to this common developmental disorder of breathing.”

The next step for the researchers is to conduct a genome-wide study of AOP among premature infants in order to identify the gene or genes responsible for the condition.

“Our work could lead to future insights on the genetic basis of the disease and ultimately more effective treatments for breathing problems in infants. If we can identify the genes involved, it’s possible we could develop screening methods for AOP and to test whether these biomarkers are predictive for respiratory conditions later in life,” said Paydarfar.

Source: University of Massachusetts Medical School