Genetics and Epigenetics of One-Carbon Metabolism Pathway in Autism Spectrum Disorder: A Sex-Specific Brain Epigenome?

• Main Authors: Veronica Tisato, Juliana A. Silva, Giovanna Longo, Ines Gallo, Ajay V. Singh, Daniela Milani, Donato Gemmati
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Genes
• Subjects: brain-epigenome; one-carbon metabolism genes; folate; SNPs; gene variants; epigenetics
• Online Access: https://www.mdpi.com/2073-4425/12/5/782

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition affecting behavior and communication, presenting with extremely different clinical phenotypes and features. ASD etiology is composite and multifaceted with several causes and risk factors responsible for different individual disease pathophysiological processes and clinical phenotypes. From a genetic and epigenetic side, several candidate genes have been reported as potentially linked to ASD, which can be detected in about 10–25% of patients. Folate gene polymorphisms have been previously associated with other psychiatric and neurodegenerative diseases, mainly focused on gene variants in the <i>DHFR</i> gene (5q14.1; rs70991108, 19bp ins/del), <i>MTHFR</i> gene (1p36.22; rs1801133, C677T and rs1801131, A1298C), and <i>CBS</i> gene (21q22.3; rs876657421, 844ins68). Of note, their roles have been scarcely investigated from a sex/gender viewpoint, though ASD is characterized by a strong sex gap in onset-risk and progression. The aim of the present review is to point out the molecular mechanisms related to intracellular folate recycling affecting in turn remethylation and transsulfuration pathways having potential effects on ASD. Brain epigenome during fetal life necessarily reflects the sex-dependent different imprint of the genome-environment interactions which effects are difficult to decrypt. We here will focus on the <i>DHFR</i>, <i>MTHFR</i> and <i>CBS</i> gene-triad by dissecting their roles in a sex-oriented view, primarily to bring new perspectives in ASD epigenetics.