Pilot Study on Subjective Efficiency of Caffeine in ADCY5-related Dyskinesia

Heterozygous mutations in the ADCY5 gene cause involuntary early-onset hyperkinetic movements. The phenotype combines chorea, dystonia and / or myoclonus with frequent facial involvement, axial hypotonia, fluctuations and / or episodes of paroxysmal dyskinesia which can be nocturnal and / or painful.

Many treatments have been tried, with no obvious efficacy. Two patients from the same family (a father and daughter) told investigators that caffeine had a dramatic effect on their paroxysmal episodes. They said that taking coffee would prevent episodes and reduce their duration (efficacy estimated at 80%), an effect specific to caffeine since it was reproduced by the ingestion of caffeine citrate capsules. Very interestingly, there is a rationale underlying this phenomenon. Indeed, caffeine is an antagonist of the adenosine A2A receptors (A2AR), receptors which activate ADCY5 and which are localized preferentially in striatal neurons expressing dopamine D2 receptors. As caffeine is an A2AR antagonist, it likely inhibits ADCY5, and therefore induces clinical improvement in patients with hyperactivity of this protein.

In addition, the investigative team noted anxiety in some of its patients, and the question of the presence of psychiatric disorders in ADCY5 patients was recently raised in the literature.

The investigative team wishes to collect standardized preliminary data by questioning patients on the effect of caffeine on their motor symptoms and their overall clinical state, and on the possible existence of psychiatric comorbidities using structured questionnaires which will be carried out by phone.