Is dementia caused by DNA ‘spelling error’ in womb?

DEMENTIA may be caused by ‘spelling mistakes’ in DNA which affect nearly one in ten people.

Scientists have an answer to the mystery over what can trigger the memory-robbing disease, which only a minority of people inherit from their parents.

They have found dementia may start in the womb, through mutations or ‘spelling mistakes’ which randomly occur as the brain cells form. The findings could lead to a dementia blood test which picks up people at risk sooner for early treatment.

Researchers led by the University of Cambridge analysed tissue from 40 dementia patients and 14 healthy people, a comparatively small study.

Their results, published in the journal Nature Communications, suggest the mutations happen spontaneously in the womb and are found in many more people than the 5 per cent who inherit dementia.

Scientists say these mutations are probably found among the brain cells of almost one in ten healthy people.

Professor Patrick Chinnery, who led the study, said: ‘These spelling errors arise in our DNA as cells divide. These mutations likely form when our brain develops before birth – they are sat there waiting to cause problems when we are older.’

A million people in Britain are expected to have dementia by 2021.