state-of-the-art therapy to treat ADDC, a rare childhood disease

This is a national first: the injection of a drug into the brain on children suffering from a rare disease, AADC. Two 10-year-old children benefited from it at the Montpellier University Hospital.

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“ It’s the neurosurgery of the 21st century! “ exclaim the professors who present their latest discovery. A national first: the injection of a drug that synthesizes dopamine and serotonin, deficient in certain organisms and which cause a rare disease called AADC.

This is a very rare disease linked to the failure of certain brain cells to make a substance called dopamine. Dopamine has a very important role for the functioning of certain parts of the brain involved in the control of movement, and also in sleep and mood.

Thus, patients with this disease have motor problems. They are very hypotonic, that is to say like “soft” without control of their muscles, they have a lot of difficulty in carrying out movements, and need help for most of the daily activities. They also have trouble sleeping and feeding difficulties.

No effective treatment is currently available. It is a genetic disease, that is to say that an individual is affected because he has an anomaly in a very small part of his genetic code (a gene), and therefore the production of dopamine is disturbed.

Two children aged around ten benefited from this experiment at the Montpellier University Hospital in December 2020 and February 2021. On December 4, 2020, the pediatric neurology and pediatric neurosurgery teams at the Montpellier University Hospital performed the intracerebral injection of ‘a gene carried by an inactivated virus to cure this rare genetic disease in children.

Gene therapy consists of delivering into a part of the body a “healthy” gene capable of replacing or repairing the “sick” gene. A harmless virus is used to carry the “healthy” gene, and the virus is then eliminated. We can consider that this composition “gene and virus” is a new type of drug.

A long operation, over 6 hours, where for 4 hours small catheters inject the drug gene.

This is the principle of gene therapy: bringing the gene to the cell, allowing it to manufacture the enzyme. It’s a cell transplant. The drug should be given to a specific area of ​​the brain without causing injury. Then wait for the transplant to take hold and for the child to manufacture this enzyme on his own.

Professor Thomas Roujeau, pediatric neurosurgeon CHU de Montpellier

It will take several weeks to see the effects of gene therapy: the team is currently in the observation phase, and the evolution of the various signs of the disease will be very regularly assessed by the teams. Three months after the first operation, signs of improvement appear.

There are improvements in sleep disorders and better concentration. We need more time to assess motor skills.

Prof. Agathe Roubertie, neuropediatrician CHU de Montpellier

Other experiments with this method have already taken place in Japan and Taiwan. Ultimately, around ten children could benefit from it in Europe. And this treatment could be applied to other neurological diseases.

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