Genetics and psychophysiology of ADHD and autism

Abstract

The paper discusses the brain mechanisms of autism and attention deficit hyperactivity disorder. It is shown that these disorders are associated with different genetic causes that create certain psychophysiological mechanisms. Nevertheless, their diagnosis is interrelated. Moreover, a child is often first diagnosed with ADHD, and then the diagnosis is changed to “autism spectrum disease”. Among the most common causes of the disease is the behavior of retrotransposons. Retrotransposons (also called transposons via intermediate RNA) are genetic elements that can amplify themselves in the genome. These DNA sequences use a “copy and paste” mechanism, whereby they are first transcribed into RNA and then converted back to identical DNA sequences via reverse transcription, and these sequences are then inserted into the genome at target sites. In humans, retro elements take up 42 % of the DNA. The conclusion is made that for the formation of an individual profile of gene expression in the neuron, the most important is the phenomenon of somatic mosaicism, due to the process of L1 retrotransposition, in addition to the classical described mechanisms of differentiation. The number of such events and their localization is significant as they are likely to contribute to the development of both autism and ADHD.