Scientists identify a protein linked to cause of AMD


A protein strongly linked to the cause of age-related macular degeneration (AMD) when its levels are raised in the blood, has been identified by a team of scientists.

The FHR4 protein was found to be present at higher levels in the blood of patients with AMD compared to individuals of a similar age without the disease.

Published in Nature Communications and funded by the Medical Research Council, the study was carried out by scientists from universities in Manchester, Cardiff, London and Nijmegen in the Netherlands, as well as the Manchester Foundation NHS Trust.

Professor Paul Bishop, study lead and consultant ophthalmologist at Manchester Royal Eye Hospital, said: ‘The combined protein and genetic findings provide compelling evidence that FHR4 is a critical controller of that part of the immune system which affects the eyes.

‘We have shown that genetically determined higher blood FHR4 levels leads to more FHR4 in the eye, which in turn increases the risk of the uncontrolled immune system response that drives the disease.

‘So apart from improving understanding of how AMD is caused, this work provides a way of predicting risk of the disease by simply measuring blood levels of FHR4. It also provides a new route to treatment by reducing the blood levels of FHR4 to restore immune system function in the eyes.

‘Because treatments options for AMD are limited, this comprehensive understanding of the biology of AMD is a huge boost for scientists finding answers to a problem which causes untold misery for thousands of people in the UK alone.’

During analysis, scientists found FHR4 in 484 patient and 522 control samples from two independent collections across Europe, as well as in the parts of the eye affected by AMD in eyes donated for research after life.

The protein was found to activate part of the immune system – the complement system – which is a major causal factor of AMD if overactive, scientists shared.

They explained that FHR4 is one of a group of proteins that regulate the complement system and the genes encoding these proteins are tightly clustered on the largest human chromosome – chromosome 1.

When the team investigated a set of genetic variants across the human genome, they found that genetic variants in this region on chromosome 1 determined the levels of FHR4 in the blood. They also found that the same genetic variants were associated with AMD.

This article was written by Optician Magazine.

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Author: Andrew McClean, Optician Magazine