Some 30% of children with autism spectrum disorder have raised blood levels of the neurotransmitter serotonin, but the relationship between this biomarker and brain function is unclear. Jeremy Veenstra-VanderWeele and Randy Blakely at Vanderbilt University in Nashville, Tennessee, and their colleagues have engineered a mouse with increased levels of blood serotonin that also exhibits behaviours characteristic of autism.

The mouse carries a variant of a gene that encodes SERT, a transporter protein that takes up serotonin into neurons and is also found in blood cells. The authors previously identified this variant in some people with autism. As pups, the mice vocalize less, and as adults, they display repetitive behaviour and are more likely to withdraw when they encounter another mouse. Raised SERT activity may lead to autism-related changes during brain development, the authors suggest.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1112345109 (2012)