Multi-gene epigenetic “stress signatures” incorporating nr3c1, fkbp5, oxtr, and bdnf could, with sufficient validation, serve as biomarkers for identifying youth with autism who are particularly vulnerable to ELS-related symptom exacerbation [35,37,44] (Forsberg et al., 2018; Lancaster et al., 2018; Wang et al., 2021). This evidence concerns the gene BDNF and autism.