An international team of researchers has identified four loci that appear to be associated with decreasing the volume of the hippocampus, according to a study published Sunday online in Nature Genetics.
The researchers led by Boston University School of Medicine ( BUSM) gathered data on hippocampal volume from 9,232 people who did not have dementia. They identified four genetic loci, including seven genes in or near these loci that appear to determine hippocampal volume.
The results show that if one of the genes is altered, the hippocampus is, on average, the same size as that of a person four to five years older. These results were replicated in two large European studies that included some mixed-age participants with cognitive impairment.
"The findings indicate that these loci may have broad implications for determining the integrity of the hippocampus across a range of ages and cognitive capacities," said Sudha Seshadri, professor of neurology at BUSM. One of the genes identified by the researchers was also shown to play a role in memory performance in a different data sample.
The identified genetic associations indicate that certain genes could influence cell death by apoptosis, brain development and neuronal movement during brain development, and oxidative stress. Additionally, the researchers found that the genes play a role in ubiquitination, which is a process by which damaged proteins are removed, whereas other genes code for enzymes targeted by new diabetes medications.
"Future studies need to further explore these genetic regions in order to better understand the role of these genes in determining hippocampal volume," added Seshadri.