Autism caused by absence of a gut bacteria? by ScienceDaily.

The absence of a one specific species of gut bacteria causes social deficits in mice, researchers report. By adding this bacteria species back to the guts of affected mice, the researchers were able to reverse some of their behavioral deficits, which are reminiscent of symptoms of autism spectrum disorders (ASDs) in humans

Hopefully it is something along these lines, that can be remedied.

hat-tip Joanne