Asthma as a Developmental Disorder

Abstract

Asthma is the most common disorder in childhood, affecting six million children in the United States. Asthma is a heterogeneous disease, but most cases either start in early life or have their roots in events occurring in utero or during the preschool years. Protective or harmful exposures, including to environmental microbes, occurring during critical developmental windows determine patterns of immune responses that often persist for a lifetime. Air pollution, tobacco smoke, and prematurity can cause congenital airway narrowing, and newborns with decreased airway function are at risk for having asthma symptoms up to adulthood. Effects of environmental exposures are modified by common genetic variations and may also be mediated by prenatal changes in the epigenetic structure of the genome. Based on this evidence, we have postulated that asthma should be considered a developmental disorder, and this concept may be applicable to other chronic medical conditions affecting both children and adults.