The causes of autism spectrum disorder (ASD) are not well understood, but research suggests that factors influencing early brain development may be involved. Polyunsaturated fatty acids (PUFAs), which include omega 3 fatty acids, are fats obtained from the diet that play key roles in early fetal brain development. It is not known whether levels of these crucial fats during pregnancy influence risk of ASD. This project will examine the relationship between PUFA levels and ASD, addressing the role of environmental risk factors in ASD (a Fiscal Year 2015 priority Area of Interest). Specifically, the goal of this project is to determine whether levels of PUFAs measured from maternal blood samples collected during pregnancy, and in a subgroup group, from newborn blood spots, differ between children with ASD and those without ASD. We will also explore whether the relationship between PUFAs and ASD differs in certain subgroups, such as by race/ethnicity, preterm birth, or child gender. Based on the importance of PUFAs in neurodevelopment, we suspect that lower levels of PUFAs may be related to ASD.

In order to address these questions, we will use data from routine screening programs in the state of California. Children with ASD (cases) will be selected from the California Department of Developmental Services (DDS), a statewide program that coordinates services for children with autism and other disabilities. Children without ASD (controls) will be selected from California birth certificates in the same year as children with ASD. PUFAs will be measured in the previously collected blood samples from pregnancy (500 cases and 500 controls), and in newborn blood spots from a subgroup (200 cases and 200 controls) using sensitive, state-of-the-art technology. Statistical analyses will examine differences in levels of maternal and newborn PUFAs between children with and without ASD, adjusting for demographic and other factors that may influence the association. Subgroup analyses will explore potential differences by major categories of race/ethnicity, gender, preterm birth, and others. Because the samples used in this study were collected during the time when PUFAs may have the greatest influence on the developing brain, associations seen here will inform on the role of PUFAs in risk of ASD.

Impact: This study has the potential to identify a new and modifiable risk factor for ASD, as PUFA levels can be changed through diet or supplements. Since most pregnant women do not meet suggested requirements for PUFA intake, efforts to increase PUFA levels could have a potentially large impact on reducing risk of ASD if our results support our hypothesis. This work could also pave the way for future studies wishing to measure PUFA levels in newborn blood spots, which are a more readily available resource given nearly universal newborn screening, but have not been widely used in studies of fatty acid measurements.

Innovation: This is the first study to measure levels of PUFAs during pregnancy in association with risk of ASD, and one of the first to use newborn blood spots to measure these fatty acids. Our study will make use of unique, existing databases and samples in order to attempt to identify a new risk factor for ASD. The results of this novel study will help us understand the role that PUFAs may play in risk of ASD.