The Principal Investigator has recently found that evidence of a polyomavirus in post-mortem brains of patients with ASD. These viruses may either reach the brain postnatally, or could be vertically transmitted from parents to offspring. Viruses are obviously environmental agents, but the vertical transmission of a virus through the paternal semen and/or the maternal egg cell represents a peculiar form of environmental pathogenesis, whereby the environmental factor mimics genetic transmission. The demonstration that viral transmission of polyomaviruses from father to offspring can indeed occur in some families with a child with ASD is a critical first step, which can ultimately pave the path to important clinical applications. The translational value of the proposed research, in terms of diagnosis, treatment, and prevention, is remarkable. Diagnostic methods to detect and quantify infections by polyomaviruses are available and relatively widespread: methods for the direct detection of viral genomes and infectious viral particles are available. Pharmacological treatments for polyomavirus infection have been developed, and Mauro Tognon, an internationally-renowned expert in the field of polyomaviruses, will collaborate on the project.