Autism spectrum disorders share common features of impaired social relationships, impaired language and communication, repetitive behaviors and a limited range of interests. Although monogenic disorders collectively account for a minority of autism cases (10 to 15 percent),  the molecular alterations in these disorders could reveal common pathways shared by disorders across the autism spectrum.

Recent studies have demonstrated the presence of 5-­hydroxymethylcytosine (5-hmC) throughout the human genome. It is thought to be an epigenetic regulator of gene expression, meaning that it alters the expression of genes without changing their underlying sequence. Unlike 5-methylcytosine  (5-mC), which appears to repress genes, 5-­hmC seems to be involved in gene activation, which is important for proper neuronal function.

Peng Jin at Emory School of Medicine in Atlanta and his collaborator Chuan He at the University of Chicago have developed a selective chemical labeling method for 5-hmC, which enables them to visualize the genome-wide distribution of 5-hmC.  Using this technology, the researchers have found that the alteration of 5-hmC at specific loci could be a common trait associated with autism-linked monogenic disorders.

Jin’s team plans to further explore the role of  5-hmC-mediated epigenetic modulation in both autism and autism-linked monogenic disorders. Their study could contribute to the identification of genetic and epigenetic risk factors for autism, and may provide insight into the molecular pathogenesis of autism spectrum disorders.