DNA methylation signatures in autism spectrum disorders

Autism Spectrum Disorders (ASD) are a group of neurodevelopmental disorders which includes autistic disorders, Asperger’s Syndrome and Pervasive Developmental Disorders not otherwise-specified according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSMV). ASD is primarily characterised by impaired reciprocal-social interaction, repetitive-stereotypic behaviours and deficits in communication skills. It has a striking male bias in the ratio of about 4.5:1. Its current prevalence rate is about 1 in 59 among 8 years old children in the USA and its prevalence is increasing at an alarming rate throughout the world, including India. Although the exact aetiology of ASD is yet to be deciphered, number of evidences show that it is influenced by both genetic and epigenetic contributions. Twin and family studies confirm the heritable nature of such disorders. Aberrant DNA methylation and post translational modifications to histone play a major role in its aetiology. Rett Syndrome and Fragile X syndrome are single gene disorders associated with ASD, while Prader Willi and Angelman’s syndrome are genomic imprinted disorders where epigenetic regulatory mechanisms play pivotal role in the disease pathogenesis. In this work, our aim was to give an overview to the DNA methylation signatures in ASD and closely associated neuropsychiatric conditions. We conclude with the discussion of the probable therapeutics that might be developed in future.