Familial dyskinesia with facial myokymia - or ADCY5-related dyskinesia - is a rare genetic disorder. It usually occurs in childhood, but there have also been cases of onset in late adolescence. The most characteristic symptoms are the uncontrolled paroxysmal movements of limbs and neck, which often also involve the face.

The severity of the disease varies based on the frequency and violence of the seizures. In the worst cases, it makes it impossible to walk and even talk, so much so that many subjects show delays in motor development. It seems that stress and anxiety contribute to worsening the severity of symptoms. On the other hand, the extent of dyskinesia tends to stabilize in adulthood.

The diagnosis of ADCY5-relata dyskinesia occurs through clinical observation and genetic tests, aimed at identifying ADCY5 gene abnormalities. The gene is expressed above all in the granular neuronal precursors of the cerebellum; the mutation could cause its overexpression.

The phenomenon could repress the hedgehog pathway of the embryonic neural tube, with all the consequences mentioned above. During the diagnosis, it is common for dyskinesia and epilepsy to be confused. However, the disease in question does not respond to epileptic drugs; usually it takes very little to exclude epilepsy with reasonable safety.

Uncontrolled facial movements can raise some doubts about multiple sclerosis and hereditary benign chorea. In these cases, the genetic test is used to identify the possible mutation of ADCY5. For the moment, there are no resolutive therapies against familial dyskinesia with facial myochemistry.

Source: orpha.net