Autism spectrum disorder (ASD) is a complex and heterogeneous neurodevelopmental condition characterized by challenges in social communication, restricted interests, and repetitive behaviors (Lord et al., 2020). The prevalence of ASD has been rising globally (Salari et al., 2022), and a well-established feature of ASD is its sex disparity in prevalence, with estimates indicating a substantial male-to-female ratio in diagnoses, typically around 3.5:1 (Loomes et al., 2017). While both genetic and environmental factors contribute to the risk of ASD (Sandin et al., 2014; Hallmayer et al., 2011), a growing body of evidence suggests that endocrine pathways play a significant role in modulating brain development, particularly those involving sex hormones and stress-related hormones. These endocrine influences may contribute to the neurobiological and behavioral phenotypes observed in ASD, as well as to the notable sex differences in ASD prevalence and presentation (Baron-Cohen et al., 2011; Baron-Cohen et al., 2015). The prenatal steroid theory of autism posits that elevated levels of fetal gonadal hormones, particularly androgens such as testosterone, influence brain development in ways that increase ASD susceptibility (Baron-Cohen et al., 2015).

Sex-hormones exert their effects during sensitive developmental windows by acting on hormone receptors that function as transcription factors, thereby regulating gene expression critical to processes such as neuronal proliferation, synaptic plasticity, and connectivity (Baud and Berkane, 2019; Crider and Pillai, 2017; McEwen and Milner, 2017). These mechanisms may shape sex-specific brain trajectories, and deviations in these pathways could contribute to ASD phenotypes. Testosterone has been linked to structural brain changes that affect social cognition and emotional processing, areas commonly affected in ASD (Auyeung et al., 2009; Wilson et al., 2021). Conversely, estrogens exhibit neuroprotective properties, which may help buffer against some of the genetic or environmental factors that contribute to ASD, potentially explaining aspects of the “female protective effect” observed in ASD prevalence (Ferri et al., 2018). Additionally, fetal exposure to high levels of sex hormones, particularly testosterone, has been associated with an increased risk of ASD, supporting the hypothesis of endocrine involvement in ASD pathophysiology (Baron-Cohen et al., 2015).

While several studies have linked elevated prenatal testosterone levels to increased ASD traits, supporting the prenatal androgen theory of autism (Baron-Cohen et al., 2015), the literature is not unanimous. For example, Kung et al. (2016) and Granillo et al. (2022) reported no significant associations between fetal testosterone levels and autistic traits in early childhood. These discrepancies may reflect differences in sample size, timing, and method of hormone measurement, or the multifactorial nature of ASD, where hormonal exposure may interact with genetic susceptibility and environmental factors. Therefore, approaches that examine the genomic regulatory role of sex hormones, as proposed in this study, may help clarify their contribution to ASD pathophysiology beyond observational associations between hormones and behavioral traits.

Beyond sex hormones, other endocrine pathways are also implicated in ASD. Cortisol, the primary glucocorticoid hormone, regulates the body's response to stress and has been associated with alterations in behavior and social processing. Dysregulated cortisol levels have been observed in individuals with ASD, suggesting that the hypothalamic-pituitary-adrenal (HPA) axis may play a role in the development or modulation of ASD symptoms (Corbett et al., 2010; Taylor and Corbett, 2014). Similarly, oxytocin and vasopressin, hormones central to social bonding and behavior, are also implicated in ASD. Studies have shown that individuals with ASD often exhibit altered levels of these hormones, which may contribute to social and behavioral differences characteristic of the disorder (Modi and Young, 2012).

This study aims to explore the functional annotations of ASD-related genes, with a focus on endocrine pathways and an assessment of the connectivity and impact of genes related to sex hormones, stress hormones, and other relevant endocrine factors. The analysis does not aim to predict individual ASD risk, but rather to assess the functional relevance of gene subsets (e.g., related to sex hormones) on the robustness of the functional network of ASD risk genes. By examining these hormonal influences, this research seeks to understand the molecular underpinnings of ASD better and shed light on potential sex-based differences in ASD pathology, contributing to a broader understanding of how endocrine factors shape ASD-related phenotypes.