Shyamal H. Mehta, MD, PhD Movement Disorders Program, Department of Neurology, 1429 Harper Street, HF-1121, Augusta, GA 30912, USA. . Current Treatment Options in Neurology
(Impact Factor: 1.94).
06/2009; 11(3):170-8. DOI: 10.1007/s11940-009-0020-x
Paroxysmal dyskinesias are a rare group of movement disorders affecting both adults and children. Based on the events that precipitate the abnormal movements, they are subdivided into paroxysmal kinesigenic dyskinesia (PKD), precipitated by sudden voluntary movements; paroxysmal nonkinesigenic dyskinesia (PNKD), which occurs at rest; paroxysmal exertion-induced dyskinesia (PED), occurring after prolonged exercise; and paroxysmal hypnogenic dyskinesia (PHD), which occurs in sleep. Paroxysmal dyskinesias can be sporadic, familial (autosomal dominant inheritance), or secondary to other disorders. Recent genetic discoveries may aid us in elucidating the pathophysiology of these disorders. PKD has been linked to the pericentromeric region of chromosome 16, PNKD is associated with mutations in the myofibrillogenesis regulator 1 (MR-1) gene on the long arm of chromosome 2 (2q32-36 locus), and PED is associated with mutations in the glucose transporter gene, GLUT1, responsible for glucose transport across the blood-brain barrier.
Lifestyle modification to avoid precipitating factors is important in the management of paroxysmal dyskinesias. Medical therapies have not been examined in controlled trials. Nevertheless, anticonvulsants have been found to be extremely effective in treating PKD and are sometimes useful in other types, suggesting that these disorders may indeed represent forms of channelopathies. Drugs such as acetazolamide, anticholinergics, levodopa, and tetrabenazine have been inconsistently successful. In rare cases with medically refractory symptoms, deep brain stimulation has also been employed. Development of successful treatments for the different paroxysmal dyskinesias rests on elucidating the pathophysiology and targeting therapy to treat the underlying perturbation.
Available from: Satoru Takahashi
- "Most patients are neurologically normal between the attacks and remain conscious through these attacks. On the basis of the events that trigger the abnormal movements, paroxysmal dyskinesias are subdivided into paroxysmal kinesigenic dyskinesia (PKD), paroxysmal exercise-induced dyskinesia (PED), and paroxysmal non-kinesigenic dyskinesia (PNKD)
[1,2]. In patients with PKD, the attacks of abnormal movements are triggered by sudden voluntary movements and last less than 1 minute
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Paroxysmal kinesigenic dyskinesia is characterized by sudden attacks of involuntary movements. It is often misdiagnosed clinically as psychogenic illness, which distresses the patients to a great extent. A correct diagnosis will improve the quality of life in patients with paroxysmal kinesigenic dyskinesia because treatment with low doses of anticonvulsants is effective for eliminating the clinical manifestations. Paroxysmal kinesigenic dyskinesia can occur independently of or concurrently with benign infantile convulsion. Identification of PRRT2 as the causative gene of benign infantile convulsion and paroxysmal kinesigenic dyskinesia allows genetic confirmation of the clinical diagnosis.
We describe the clinical features of a Japanese family with either paroxysmal kinesigenic dyskinesia or benign infantile convulsion. A PRRT2 missense mutation (c.981C > G, p.Ile327Met) was identified in two patients with benign infantile convulsion and three patients with paroxysmal kinesigenic dyskinesia as well as in two unaffected individuals. Allowing incomplete penetrance in the mutation carriers, this mutation co-segregated completely with the phenotype. The patients with paroxysmal kinesigenic dyskinesia had been misdiagnosed with psychogenic illness for many years. They were correctly diagnosed with paroxysmal kinesigenic dyskinesia when their children visited a pediatrician for benign infantile convulsion. Treatment with carbamazepine controlled their involuntary movements completely.
Paroxysmal kinesigenic dyskinesia is a treatable movement disorder that is often misdiagnosed clinically as psychogenic illness. It is important to note that two clinically distinct disorders, benign infantile convulsion and paroxysmal kinesigenic dyskinesia, are allelic conditions caused by PRRT2 mutations. Paroxysmal kinesigenic dyskinesia should be suspected in families with a child with benign infantile convulsion.
Available from: Waqas Khan
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ABSTRACT: We report a rare case of familial paroxysmal kinesigenic dyskinesia. A 42-year-old woman and her 13-year-old daughter both presented with episodic curling of their hand and arm. These events were triggered by sudden movements and would last several seconds. Both patients' symptoms were unilateral and their physical and neurological examinations were normal. Treatment with carbamazepine improved their symptoms. Although an uncommon movement disorder it is important to recognize the clinical presentation of paroxysmal kinesigenic dyskinesia as most patients respond very well to medical treatment.
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