Bugs in the program: can pregnancy drugs and smoking disturb molecular reprogramming of the fetal germline, increasing heritable risk for autism and neurodevelopmental disorders?

In a seeming paradox, the prevalence of autism spectrum disorder (ASD) has surged, while at the same time research has pointed to the strong heritability of this neurodevelopmental pathology. Here an autism research philanthropist suggests a biological phenomenon of exogenously induced ‘gamete disruption’ that could reconcile these seemingly contradictory observations. Mining information from her own family history and that of her fellow autism parents, while also engaging with the scientific community, she proposes that a subset of the autisms may be rooted in a variety of molecular glitches in parental gametes induced by certain acute exposures during the parents’ own fetal or neonatal development. These exposures include but are not limited to synthetic hormone drugs, tobacco, and general anesthesia. Consistent with this hypothesis, animal models have demonstrated adverse neurobehavioral outcomes in grandoffspring of gestating dams exposed to hormone-disrupting compounds, tobacco components, and general anesthesia. A recent epidemiological study showed a link between grandmaternal smoking and risk for ASD in grandoffspring through the maternal line. Given the urgency of the autism crisis, combined with the biological plausibility of this mostly unexplored paradigm, the writer contends that questions of nongenetic inheritance should be a priority in autism research.