A gene that boosts intelligence could offer new hope to sufferers of dementia, it was revealed today.
Researchers in the U.S. found a protein produced by the gene could be synthesised and used to fight the condition.
The study, funded by the U.S.-based National Institutes of Health, found the protein called klotho boosts brain skills such as thinking, learning and memory.
It is believed it could increase the strength of connections between nerve cells in the brain.
Dena Dubal, professor of neurodegeneration at UCSF, the lead author, said: ‘This could be a major step towards helping millions around the world who are suffering from Alzheimer’s disease and other dementias.
‘If we could boost the brain’s ability to function, we may be able to counter dementias.’
Researchers found the protein could raise IQ by up to six points – whatever the age of the person taking it – raising the possibility that a drug could become available to make people cleverer.
‘Our results suggest klotho may increase the brain’s capacity to perform everyday intellectual tasks,’ said coauthor Lennart Mucke, professor of neuroscience at the University of California San Francisco.
People who have one copy of a variant, or form, of the kloto gene, called KL-VS, tend to live longer and have lower chances of suffering a stroke whereas people who have two copies may live shorter lives and have a higher risk of stroke.
In the study, researchers found that people who had one copy of the KL-VS variant performed better on a battery of cognitive tests than subjects who did not have it, regardless of age, sex or the presence of the apolipoprotein 4 gene, the main genetic risk factor for Alzheimer’s disease.
The klotho gene provides the blueprint for a protein made primarily by the cells of the kidney, placenta, small intestine, and prostate.
A shortened version of the protein can circulate through the blood system. Blood tests showed that subjects who had one copy of the KL-VS variant also had higher levels of circulating klotho protein. The levels decreased with age as others have observed.
The researchers speculate that the age-related decrease in circulating levels of klotho protein may have caused some of the decline in performance on the cognitive tests.
Researchers then genetically engineered mice to overproduce klotho protein. The klotho-enhanced mice lived longer and had higher levels of klotho in the blood and in a brain area known as the hippocampus, which controls some types of learning and memory.
Similar to human studies, the klotho-enhanced mice performed better on a variety of learning and memory tests, regardless of age.
The investigators tested a variety of cognitive skills, including learning, memory, and attention. More than 700 subjects, 52 to 85 years old were tested as part of three studies.
None had any sign of dementia. Consistent with previous studies, 20 to 25 per cent of the subjects had one copy of the KL-VS variant and performed better on the tests than those who had no copies.
Performance on the tests decreased with age regardless of whether a subject had one or no copies of the KL-VS gene variant.