Credit: University of Liverpool

Researchers say a key blood protein discovery is a “major step forward” in understanding age-related blindness.

The FHR4 protein is found in blood levels and is thought to be the leading cause of amacular-degeneration (AMD), which causes blindness.

In a Europe-wide blood sample collection, researchers used a genetic technique to analyse genes related to increased levels of FHR4 in patients with AMD.

A test involving 484 patients and 522 control test subjects showed that the genetic changes caused an “uncontrolled activation” of an area of the body’s immune system named the complement system.

They suggest the “over-activation” of the complement system causes AMD.

University of Manchester Professor Simon Clark says the discovery shows a “direct link”, assisting in “identifying a group of potential therapeutic targets to treat this debilitating disease”.