Olivopontocerebellar Atrophy 1 Synonyms 2 Symptoms 3 Causes 4 Related Disorders 5 Therapies: Standard 6 Therapies: Investigational 7 Resources 8 References Synonyms -------- OPCA Atrophy, Olivopontocerebellar DISORDER SUBDIVISIONS Olivopontocerebellar Atrophy I (SCA1; OPCA I, Menzel Type OPCA) Olivopontocerebellar Atrophy II (OPCA II, Fickler-Winkler Type) Olivopontocerebellar Atrophy III (OPCA III; OPCA With Retinal Degeneration) Olivopontocerebellar Atrophy IV (OPCA IV; Schut-Haymaker Type OPCA) Olivopontocerebellar Atrophy V (OPCA V; OPCA With Dementia and Extrapyramidal Signs) Information on the following diseases can be found in the Related Disorders section of this report: Friedreich's Ataxia Marie's Ataxia Ataxia Telangiectasia Charcot-Marie-Tooth Disease Symptoms -------- Olivopontocerebellar Atrophy (OPCA) is characterized by loss of nerve cells (neurons) in the cortex of the brain, base of the pons section of brainstem (basis pontis), and inferior olivary nuclei which is a prominence on the surface of the lower part of the brain (medulla oblangata). Loss of these neurons results in impaired muscle coordination (ataxia), tremor, involuntary movement, and a speech disturbance (dysarthria). Five clinical types of OPCA have been described, depending on additional findings, such as sensory loss, retinal degeneration, ophthalmoplegia, and extrapyramidal signs. However, cases have occurred which have defied classification in any of these five categories. A wide variation in severity and age of onset may be found in any of the five recognized classifications of Olivopontocerebellar Atrophy. Olivopontocerebellar Atrophy I (Menzel type OPCA) usually begins in the third or fourth decades of life, with an average onset at thirty years of age. In addition to cerebellar degeneration, other areas of the body become affected with speech abnormalities and/or tremors. Involuntary movements (chorea) may also occur. Olivopontocerebellar Atrophy II (OPCA II, Fickler-Winkler or Dejerine- Thomas type) differs from OPCA type I by a lack of involuntary movements. Onset of this disorder usually begins at approximately fifty years of age. The exact nature of this form of cerebellar atrophy is not well understood. Olivopontocerebellar Atrophy III (OPCA III; OPCA with retinal degeneration) is characterized by retinal degeneration. This form of OPCA usually begins during middle age, although it can begin at any age. It is also marked by blindness, tremor, weakness and impaired muscle coordination. Olivopontocerebellar Atrophy IV (OPCA IV; Schut-Haymaker type OPCA) is characterized by a form of paralysis (spastic paraplegia). The atrophy seems to be limited to the inferior olivary nucleus and cerebellum with varying involvement of the pons area of the brain. Abnormalities of the spinal cord and some of the cranial nerves may also occur. Symptoms usually begin at approximately twenty-five years of age. Olivopontocerebellar Atrophy V (OPCA V; OPCA with dementia and extrapyramidal signs) is characterized by cerebellar atrophy, tremors, ataxia and abnormal sensation, rigidity and mental deterioration. This disorder usually begins during adult life. Walking, writing and speech often become difficult as the disorder progresses. Causes ------ Four of the five identified forms of Olivopontocerebellar Atrophy (OPCA) are inherited as autosomal dominant traits. OPCA II is inherited as an autosomal recessive trait. Human traits including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed "dominating" the normal gene and resulting in appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.) In recessive disorders, the condition does not appear unless a person inherits the same defective gene from each parent. If one receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will show no symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is twenty-five percent. Fifty percent of their children will be carriers, but healthy as described above. Twenty-five percent of their children will receive both normal genes, one from each parent and will be genetically normal.) The defective gene that causes Olivopontocerebellar Atrophy I (SCA1) is thought to be located on the short arm of chromosome 6 (6p24-p23). Some studies suggest that this defective gene may be very unusual. It may produce varying amounts of extra genetic material (trinucleotide repeats) that may be responsible for the severity of symptoms as well as the age of onset. Research suggests that people who have symptoms of this disease early in life may have a larger gene size than those with late-onset disease. Related Disorders ----------------- Ataxia. It usually begins during childhood or the teen years. Also known as Friedrich's Ataxia. Marie's Ataxia is a neuromuscular syndrome inherited as a dominant trait. Also known as Pierre Marie's Disease or Hereditary Cerebellar Ataxia, it is characterized by a later onset of neurological and coordination disturbances. The syndrome usually begins between thirty and forty years of age and may not be as disabling as Friedreich's Ataxia. Initially, those affected may walk unsteadily and tend to fall frequently. Loss of coordination in the arms and speech disturbances may also occur. In later stages slight loss of vision, and loss of pain or touch sensations, may also occur. Tremors may develop when conscious motion is attempted. Swallowing and clearing of secretions may eventually become difficult if the throat muscles are affected. Charcot-Marie-Tooth Disease (CMT) is a hereditary neurological disorder characterized by weakness and atrophy, primarily in the legs. Disappearance of the fatty shield surrounding the nerve cells (segmental demyelination of peripheral nerves), and associated degeneration of part of the nerve cells (axons) characterize this disorder. Ataxia Telangiectasia, also known as Louis-Bar Syndrome, is an inherited progressive cerebellar ataxia that usually begins during infancy. It involves progressive loss of coordination in the limbs, head and eyes with a below-normal immune response to infections. In later stages, dilated blood vessels (telangiectasias) appear in the eyes and skin. Individuals with this form of Ataxia are more susceptible to sinus and lung infections and tend to have tumors (neoplasms). Ataxia Telangiectasia may be misdiagnosed as Friedreich Ataxia until dilated blood vessels appear in the skin (telangiectasias). Therapies: Standard -------------------- Treatment of Olivopontocerebellar Atrophy is symptomatic and supportive. Continuous medical supervision to avoid potential complications involving the heart, lungs, spine, bones and muscles is recommended. Prevention of infection is a challenge in the care of people in the advanced stages of Olivopontocerebellar Atrophy. Physical therapy may be recommended by a physician. Drugs may be useful in treating some symptoms. Propranalol may be effective against static tremors, and less often against intention tremors. Static tremors can occur when the affected individual is not moving, whereas intention tremors occur when the patient makes intentional movements. Dantrolene sodium may help some patients with muscle spasms of the legs. These drugs should be carefully monitored by a physician to limit the possibility of toxicity. Genetic counseling is recommended for patients and their families. Other treatment is symptomatic and supportive. Therapies: Investigational --------------------------- Olivopontocerebellar Atrophy patients may be treated for spasticity using the drug baclofen. Genetic investigators are trying to identify the gene which causes this syndrome. Other experimental drugs, cell cultures, and analysis of central nervous system tissues are also under study. This disease entry is based upon medical information available through March 1994. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources --------- For more information on Olivopontocerebellar Atrophy, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 (203) 746-6927 (TDD for the hearing impaired) National Ataxia Foundation 750 Twelve Oaks Center 15500 Wayzata Blvd. Wayzata, MN 55390 (612) 473-7666 NIH/National Institute of Neurological Disorders & Stroke (NINDS) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5751 (800) 352-9424 International Tremor Foundation 833 W. Washington Blvd. Chicago, IL 60607 (312) 733-1893 For genetic information and genetic counseling referrals: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE References ---------- MENDELIAN INHERITANCE IN MAN, 7th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 537-539, 874. OLIVOPONTOCEREBELLAR ATROPHY WITH DEMENTIA, BLINDNESS, AND CHOREA. RESPONSE TO BACLOFEN: D.A. Trauner; Arch Neurol (August 1985, issue 42(8)). Pp. 757-758. OLIVOPONTOCEREBELLAR ATROPHY. A REVIEW OF 117 CASES: J. Berciano; J Neurol Sci (February 1982, issue 53 (2)). Pp. 253-272. AN APOLOGY AND AN INTRODUCTION TO THE OLIVOPONTOCEREBELLAR ATROPHIES: R.C. Duvoisin; Adv Neurol (1984, issue 41). Pp. 5-12.