Neurogenetics: Episodic Ataxia

ying-hui fu's & louis ptáček's
	*laboratories of neurogenetics*


Paroxysmal Dyskinesia Periodic Paralysis Episodic Ataxia Migraine Epilepsy Photic Sneeze Reflex	episodic ataxia Episodic ataxia, a disorder affecting the cerebellum, is a rare inherited syndrome of intermittent ataxia. Affected individuals are normal between attacks but become ataxic under stressful conditions and with fatigue. There are two distinct forms, both with an early onset of symptoms and episodic attacks of ataxia responsive to acetazolamide (AZM). Episodic Ataxia type 1 (EA1), an autosomal dominant disorder involving both the central and the peripheral nervous system, is characterized by attacks of ataxia and persistent myokymia, a form of involuntary muscular movement. Episodes of ataxia, with gait imbalance and slurring of speech, occur spontaneously or can be precipitated by sudden movement, excitement, or exercise. The attacks generally last from seconds to several minutes at a time and may recur many times a day. Episodic Ataxia type 2 (EA2), is an autosomal dominant disorder with episodes of markedly impaired upper-body ataxia lasting hours to days, with interictal eye movement abnormalities. Exertion and stress commonly precipitate the episodes. Often the episodes of ataxia resolve with AZM treatment. In some individuals, there may be a gradual baseline ataxia with evidence of cerebellar atrophy. Affected patients also may have migraine; some even complain of basilar migraine. Our Research Linkage analysis of several large pedigrees with EA1 mapped the disease locus to 12p13, near a cluster of three potassium channel genes: KCNA1, KCNA5 and KCNA6. Based on the clinical phenotype and its analogy to episodic disorders of muscle, ion channel genes were considered good candidate genes for EA1. The disease locus in EA2 in several pedigrees was localized to chromosome 19p. Our Laboratories Sometimes, symptoms caused by other medical conditions can mimic the effect of genetic mutations. In such cases, diagnosis and treatment of the condition is most effectively provided through traditional medical channels. Academic research laboratories such as ours do not usually provide these services; rather we are focused on genetic discoveries we hope will lead to defining these future diagnostic and treatment pathways. Study Status We are currently studying the genetic mutation(s) associated with this condition and are not collecting additional samples at this time. However, research directions change with every new discovery. If you would like to be considered for future research studies on EA, please contact the Clinical Coordinator listed below. What Does Study Participation Involve? 1. As an initial screening process, you will be asked to provide information describing your family disease history. This information is used to help researchers assess your medical condition. 2. If your condition appears to match the condition currently under study, you may be asked to submit additional information, including medical records and/or test results that will be used in the medical evaluation. 3. You will be asked to donate a blood sample (approximately 2-3 tablespoons) which we will use to isolate the DNA that we study. Contact Kristin Wong, Clinical Coordinator University of California San Francisco Department of Neurology, MC 2922 1550 Fourth St., Room 546 San Francisco, CA 94158-2324 USA Tel: +1.415.502.3976 Fax: +1.415.502.5641 Email: kristin.wong2@ucsf.edu
	Quick Links: For more information about Ataxias, please visit the following sites: National Ataxia Foundation Neuromuscular Disease Center MedlinePlus: Movement Disorders National Organization for Rare Disorders National Institute of Neurological Disorders & Stroke National Society of Genetic Counselors
	circadian rhythm & sleep \| episodic diseases \| neurodegeneration
	UCSF - Department of Neurology, MC 2922 Fu & Ptáček Laboratories 1550 Fourth St., Room 548 San Francisco, CA 94158-2324 USA tel: +1.415.502.5614 fax: +1.415.502.5641
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