Which are the causes of Paroxysmal Kinesigenic Choreathetosis / Dyskinesia?

Paroxysmal Kinesigenic Choreathetosis (PKC), also known as Paroxysmal Kinesigenic Dyskinesia (PKD), is primarily caused by genetic mutations that disrupt the electrical stability of neurons in the brain's movement centers. While the condition is often hereditary, symptoms are triggered by sudden voluntary movements, representing a complex interplay between a genetic predisposition and environmental physical stimuli.

What is the genetic basis of Paroxysmal Kinesigenic Choreathetosis?

The most significant breakthrough in understanding Paroxysmal Kinesigenic Choreathetosis is the discovery of mutations in the PRRT2 gene (Proline-Rich Transmembrane Protein 2). This gene provides instructions for making a protein that regulates neurotransmitter release. When PRRT2 is mutated, the brain’s "brakes" on electrical signaling become less efficient. Approximately 70% to 80% of familial cases of Paroxysmal Kinesigenic Choreathetosis are linked to this specific gene, which follows an autosomal dominant inheritance pattern.

How do environmental factors trigger Paroxysmal Kinesigenic Choreathetosis?

In Paroxysmal Kinesigenic Choreathetosis, the underlying genetic mutation does not cause constant movement problems. Instead, it lowers the threshold for an "electrical storm" in the basal ganglia. Clinical triggers typically include:

• Sudden voluntary movements (e.g., standing up quickly or starting to run).


• Startle responses or sudden emotional excitement.


• Hyperventilation or high-stress situations.

Are there non-genetic causes of this condition?

While most cases are primary (genetic), secondary Paroxysmal Kinesigenic Choreathetosis can occur due to brain injury or metabolic disturbances. These include:

1. Multiple sclerosis or other demyelinating diseases.


2. Structural brain lesions, such as tumors or stroke.


3. Hypoparathyroidism or other electrolyte imbalances.


4. Perinatal brain injury or hypoxic-ischemic encephalopathy.

Is the etiology of Paroxysmal Kinesigenic Choreathetosis fully understood?

While the role of PRRT2 is well-established, researchers continue to study why Paroxysmal Kinesigenic Choreathetosis presents with such variable severity even within the same family. Current research is focused on whether modifier genes or environmental factors influence the frequency of these episodes and how the brain compensates for these electrical instabilities over time.

Next steps

• Consult a neurologist specializing in movement disorders to discuss genetic testing for PRRT2.


• Keep a movement diary to identify specific physical triggers for your Paroxysmal Kinesigenic Choreathetosis.


• Join the DiseaseMaps.org community to connect with other patients and share your journey with Paroxysmal Kinesigenic Choreathetosis.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Paroxysmal Kinesigenic Dyskinesia.


• Orphanet: Paroxysmal kinesigenic choreoathetosis (ORPHA:182062).


• OMIM (Online Mendelian Inheritance in Man): Dyskinesia, Familial Kinesigenic, 1 (Entry #128200).


• PubMed: "PRRT2-associated paroxysmal kinesigenic dyskinesia: A comprehensive review."