A study in mice has found that genes linked to autism and schizophrenia are only switched on during the early stages of brain development.
The study adds to the evidence that autism and schizophrenia are neurodevelopmental disorders, a term describing conditions that originate during early brain development.
The researchers from the University of Oxford, King's College London and Imperial College London studied gene expression in the brains of mice throughout their development, from 15-day old embryos to adults.
The research focused on cells in the 'subplate', a region of the brain where the first neurons (nerve cells) develop. Subplate neurons are essential to brain development, and provide the earliest connections within the brain.
The study showed that certain genes linked to autism and schizophrenia are only active in the subplate during specific stages of development.
"The majority of the autism susceptibility genes are only expressed in the subplate of the developing mouse brain. Many can only be found at certain stages of development, making them difficult to identify at later stages using previous techniques," explained Dr Anna Hoerder-Suabedissen, who led the study at the University of Oxford.
The group were able to map gene activity in full detail thanks to powerful new methods, which allowed them to dissect and profile gene expression from small numbers of cells. This also enabled them to identify the different populations of subplate neurons more accurately.
Subplate neurons were first discovered in the 1970s by Professors Ivica Kostovic and Pasko Rakic of Yale University.
"I am excited to see tangible genetic links supporting, even indirectly, the idea of a possible role of the transient embryonic subplate zone in the origin of disorders such as autism and schizophrenia," said Professor Rakic.
"If this is possible to show in mice, where the subplate is relatively small, it is likely to be even more pronounced in humans, where it is much more evolved," he added.
Their results are published in Proceedings of the National Academy of Sciences. (ANI)