Gene expression differs in the brains of men and women

Neurological conditions can impact the sexes differently. For example, boys are several times more likely than girls to develop autism, while multiple sclerosis is more prevalent among females. According to a recent study in Nature Communications, this inequality may be down to differences in how certain genes are expressed in male and female brains.

An international team of scientists, including Daniah Trabzuni working at the Institute of Neurology in University College London, on a scholarship from the King Faisal Specialist Hospital and Research Centre in Saudi Arabia, studied brain and spinal cord samples from 137 US Caucasians post-mortem.

The researchers discovered that 2.6% of the genes in all brain cells were expressed differently in men and women. In most cases, this was because of how the RNA encoded by the genes were translated into proteins, rather than differences in the levels of gene expression. For example, NRXN3, a gene implicated in autism, is transcribed into two slightly different forms, one of which is more common in men.

These differences can affect some genetic pathways more than others. For example, two immune-related genetic pathways are enriched in the white matter of women's brains. Since multiple sclerosis is believed to be an immune-mediated disorder, this might explain its greater incidence in women.

"[These findings] will move forward our understanding of the underlying molecular mechanisms of complex neurological diseases, and will support the neuroscience community with a resource which will bring functional insights," says Trabzuni.

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