Sexual dimorphism in autism: exploring differences in gene expression as a possible etiological factor

Abstract

Autistim Spectrum Disorder (ASD) is characterized by impairments in social communication, coupled with repetitive and restricted patterns of behavior, interests or activities. ASD is a genetically heterogeneous disorder (with different genes and inheritance patterns involved in each patient) that affects about 1.5% of the population and that presents a strong deviation in sexual proportion among those affected: on average, there are 4 affected men for each affected woman. Although there are some theories to explain this deviation in sexual proportion, the physiological mechanisms behind this phenomenon are not fully understood. Transcriptome studies of autistic patients have been consistently showing the dysregulation of co-expression modules in neuronal cells in these patients. Therefore, considering that this dysregulation of expression might be the triggering factor of ASD, a mechanism that could justify the deviation of sexual proportion in the disorder would be a basal differential regulation of cerebral gene expression between male and female individuals. To evaluate this hypothesis, in this work we aim to: (a) analyze whether the modules of co-expressed genes identified in fetal brains of temporal windows and regions previously implicated in ASD differ between the sexes in terms of structure or levels of expression; and (b) to analyze whether the distribution of genes that have potentially pathogenic mutations in autistic patients of different sexes differs in these co-expression networks. We believe that the co-expression network analysis, as a systemic biology approach, can bring a deeper understanding of the differences in the regulation of gene expression in brains of men and women, contributing to the better clarification of sexual dimorphism in ASD and possibly directing patients' genetic analyzes differently between genders.