Alzheimer’s ‘could be transmitted from human to human’

ALZHEIMER’S can be ‘transmitted’ between humans, scientists believe, after a study found that at least five people had ‘caught’ the disease following a rare medical procedure.

The patients were among 1,848 children who had received a human growth hormone that was unknowingly infected with the ‘sticky’ proteins which cause the condition.

All five got the same early-onset form of Alzheimer’s, with others who received the same treatment now considered ‘at risk’.

The hormones, taken from dead donors between 1959 and 1985, were used to treat people with growth conditions in the UK before synthetic growth hormones were introduced.

But scientists believe other procedures may carry a risk of spreading Alzheimer’s as the infectious proteins, or ‘prions’, can survive sterilisation. Professor John Collinge, of University College London, said: ‘These patients were given a specific and long-discontinued treatment which involved injecting them with material now known to have been contaminated with disease-related proteins.

‘We are now planning to look at ways of destroying the prions from surgical equipment.’

Alzheimer’s was believed to come in two forms – a ‘sporadic’ variant suffered by many people over 65 and a genetic earlyonset type. The UCL scientists say they have now identified a third variant, which can be passed from person to person.

The infected hormone was stored in a UK Department of Health archive as a dried powder. Scientists tested this powder on mice and found it triggered the production of proteins that cause Alzheimer’s.

Prof. Collinge said those given the infected hormone ‘were notified many years ago they were at risk of developing CJD (Creutzfeldt-Jakob disease) – there is now a risk of them developing Alzheimer’s’.

But he stressed the research is based on a small number of people and involves medical practices no longer used. He added: ‘You can’t “catch” Alzheimer’s, it is not transmissible in the sense of a viral or bacterial infection.

‘These rare transmission routes are where people have been accidentally injected with infected human tissue... This will probably affect a relatively small number of patients.’

He added that the new findings could help researchers treat Alzheimer’s in future.