Alzheimer's: a simple blood test to detect the risk of disease

Japanese and Australian researchers have succeeded in developing a blood test that can detect a protein linked to Alzheimer's disease, 20 to 30 years before the appearance of the first symptoms, currently too late in the course of the disease. This test would allow to diagnose the pathology before irreversible brain lesions causing the symptoms are installed.

Alzheimer's disease is a neurodegenerative pathology that leads to the progressive and irreversible loss of neurons, especially neural circuits, and therefore associated mental functions, including memory. It is the most common cause of dementia in humans, affecting an average of 900,000 French and 33 million people worldwide.

Diagnosis too late for treatment

In general, the disease is diagnosed in people over 65 years old, at a stage where the lesions are already installed in the brain, with plaques of a cluster of beta-amyloid proteins, which block the normal functioning of the system nervous. No treatment can cure it at this stage, but earlier treatment of patients could delay or even stop the progression of the disease.

Faced with the frequency of the pathology, medical research is active to find a way to advance the diagnosis, before the deficit symptoms, and it seems that Japanese and Australian researchers have succeeded. They made an extraordinary discovery: a blood test to diagnose the disease 20 to 30 years before the first symptoms. Led on 373 volunteers, their study published in Nature, achieved a success rate of 90%.

The identification of beta-amyloid in blood

This blood test can identify high levels of beta-amyloid. Present at a high level in the brain, this protein can be a symptom of Alzheimer's disease. Scientists have discovered that it also accumulates in the patient's body between 20 and 30 years before the appearance of the first deficit symptoms. "From a small sample of blood, our method allows us to measure the level of beta-amyloid protein, even if their concentration is very low," said Koichi Tanaka, a molecular biologist at the Center for Developmental Disease. advanced medicine for dementia in Obu, Japan.

But the opinions of the experts diverge. "All people who have beta amyloid in the brain are not necessarily affected by dementia, and all those who have dementia do not necessarily have beta amyloid in the brain," says CNN Rob Howard researcher at University College London. It will probably be necessary to deepen research around this screening technique before it is unanimously approved. As it stands, it represents a very serious and much less invasive path than the lumbar puncture that is currently required for early diagnosis in people at risk.