A gene associated with Alzheimer's may be visible in the brain and have an effect on cognition as "early as childhood", according to a new study. Read more: Alzheimer's disease and dementia: what's the difference?
The study looked at genes – in particular the epsilon(ε)4 variant of the apolipoprotein-E gene – that had been identified in children.
Those with the ε4 gene had previously been found to have developed Alzheimer's more often than those with ε2 or 3; other variants of the gene.
"Studying these genes in young children may ultimately give us early indications of who may be at risk for dementia in the future and possibly even help us develop ways to prevent the disease from occurring or to delay the start of the disease," said Linda Chang professor of medicine at University of Hawaii, who led the study.
More than 1,185 children aged between three and 20 undertook brain scans and tests of "thinking and memory skills". The study found that "children with any form of the ε4 gene had differences in their brain development compared to children with ε2 and ε3 forms of the gene", and that these differences were seen in areas of the brain affected by Alzheimer's. In children with the ε4 gene, the hippocampus was 5 per cent smaller than those without.
"These findings mirror the smaller volumes and steeper decline of the hippocampus volume in the elderly who have the ε4 gene," said Chang.
The children with the ε4 genotypes also scored lower on cognitive tests such as memory and verbal reasoning, with scores up to 50 per cent lower on texts of executive function and working memory. The youngest children also had scores "up to 50 per cent lower" on tests of attention.
The team noted that its study was cross-sectional, meaning that "the information is from one point in time for each child".
Other genetic markers have been discovered to predict Alzheimer's. A 2015 study found that an allele, or variant form of a gene, commonly associated with Alzheimer's also conveys an increased risk of late-life depression. And VR has been used to predict the early onset of the disease.
Claims about being able to diagnose, or spot indicators of, Alzheimer's in childhood should also be treated with caution. Having the gene doesn't necessarily mean a person will develop the disease, only that it may be an indicator.
Further research will also need to be done to confirm the link. If proven the findings will likely trigger an ethical debate on whether to tell those who carry the gene.
This article was originally published by WIRED UK
