Scientists find blood biomarker that opens door to CTE diagnosis in living patients

• Condition is prevalent in rugby and American football

• Scientists are optimistic of significant breakthrough

Scientists have moved a step closer to diagnosing the degenerative brain condition chronic traumatic encephalopathy in living people, after a study found a blood biomarker that identifies an advanced form of the disease.

As things stand CTE, which is caused by repeated trauma to the head and is especially prevalent in collision and contact sports such as American football, rugby and football, can be diagnosed only after death by examining brain tissue.