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Genes responsible for the size of cerebral structures

​A crossover study in neuroimaging and genetics has linked genetic mutations to variations in the size of deep brain structures. This is a new step in evaluating the risk factors for developing a neurodegenerative disease.

Published on 5 February 2015

​The subcortical regions, buried within the brain, constitute a bridge between the cortex and the peripheral areas particularly dedicated to motor skills and memory. Their size has an effect on cognitive performance, a phenomenon observed in Alzheimer’s disease. An international study involving 193 laboratories compared MRI imaging data with genetic analyses from 30,700 individuals, in order to find possible genetic variants responsible for variations in the size of the subcortical regions.

​The CEA-I2BM (in partnership with INSERM, the CNRS and the University of Bordeaux) has been working since 1995 on the combination of imaging and genetics. Pioneers in this field, the CEA researchers conducted MRI analyses on cohorts of no less than 2,000 subjects for this study. The magnitude of data collected has led to an unprecedented level of statistical analyses. Their result: the volumes of different subcortical structures prove to be genetically conditioned. Indeed, five genetic variants were linked to an abnormally small size in certain subcortical regions, including the putamen, which is involved in the control of movement. Another genetic variant was directly linked to a small hippocampus, an essential area for memorization processes. The identification of these genetic abnormalities opens up a new field in exploration of normal and pathological brain development. Moreover, knowing the subcortical mapping of an individual would allow a more accurate assessment of the risk factors involved in developing a neurodegenerative disease such as Parkinson’s or Alzheimer’s.
Localization of certain gray matter clusters situated deep within the brain (also known as subcortical structures), including the caudate nucleus (CAU), the putamen (PUT), the globus pallidus (GP), the thalamus (THA), and the hippocampus (HIP). Some of these structures are involved with cortical areas (CTX) in a circuitry (yellow arrows) that ensures the execution and control of movements (illustration: Neurofunctional Imaging Group, UMR5296, CEA/DSV/I2BM, CNRS, University of Bordeaux).


This study was published on January 21 in the journal Nature.

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