Mental health risk genes found in the developing brain

Mental health risk genes found in the developing brain

By Liz Lockhart

A huge study, which was headed by Yale University researchers, has discovered that most genes that are associated with psychiatric illnesses are expressed in the developing human brain even before birth.

Also found were hundreds of genetic differences between males and females as their brains develop in the womb.

The study is published in the journal ‘Nature’.

86% of 17,000 human genes studied are recruited in the effort to create a hundred billion brain cells and the innumerable quantity of connections between them.

This massive study tracked which genes are involved in development and also where and when they are activated.

The senior author of the study, Nenad Sestan, associate professor of neurobiology and researcher for the Kavli Institute for Neuroscience said ‘We knew many of the genes involved in the development of the brain, but now we know where and when they are functioning in the human brain.  The complexity of the system shows why the human brain may be so susceptible to psychiatric disorders.’

1,340 tissue samples were taken from 57 individuals aged from 40 days after conception through to 82 years of age.  The study could then identify genes expressed in the human brain as well as when and where in the brain they were expressed. 

This analysis of 1.9 billion data points has provided a map of genetic activity in the brain at different points in development and shows us how much of the human brain is shaped before birth.

The researchers analysed genes and variants previously proven to be linked to autism and schizophrenia.  The symptoms of these two conditions are evident in the first few years of life, in the case of autism and during early adulthood in the case of schizophrenia.  This study shows molecular evidence of expression of these suspect genes prior to birth.

‘We found a distinct pattern of gene expression and variations prenatally in areas of the brain involving higher cognitive function.  It is clear that these disease-associated genes are developmentally regulated,’ said Sestan.

The team which contributed to this study was made up of researchers from the Lieber Institute for Brain Development, Newcastle University, National Institute of Mental Health and Virginia Commonwealth University. 

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