$Unique_ID{BRK04044} $Pretitle{} $Title{Neuropathy, Congenital Hypomyelination} $Subject{Neuropathy Congenital Hypomyelination CHN Congenital Dysmyelinating Neuropathy Congenital Hypomyelinating Polyneuropathy CHN Congenital Hypomyelination Congenital Hypomyelination Neuropathy Congenital Hypomyelination Onion Bulb Polyneuropathy Congenital Neuropathy Hypomyelination Congenital Neuropathy Early Infantile Neuropathy Infantile Neuropathy Hypomyelination Neuropathy Dejerine-Sottas Disease Guillain-Barre Syndrome } $Volume{} $Log{} Copyright (C) 1990 National Organization for Rare Disorders, Inc. 822: Neuropathy, Congenital Hypomyelination ** IMPORTANT ** It is possible that the main title of the article (Congenital Hypomyelination Neuropathy) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms CHN Congenital Dysmyelinating Neuropathy Congenital Hypomyelinating Polyneuropathy (CHN) Congenital Hypomyelination Congenital Hypomyelination Neuropathy Congenital Hypomyelination (Onion Bulb) Polyneuropathy Congenital Neuropathy caused by Hypomyelination Congenital Neuropathy Early Infantile Neuropathy Infantile Neuropathy Hypomyelination Neuropathy Information on the following disorders can be found in the Related Disorders section of this report: Dejerine-Sottas Disease Guillain-Barre Syndrome General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Congenital Hypomyelination Neuropathy is a neurological disorder present at birth. Major symptoms can include respiratory difficulty, muscle weakness and incoordination, poor muscle tone, absence of reflexes, difficulty in walking, and/or impaired abilities to feel or move part of the body. Symptoms Symptoms of Congenital Hypomyelination Neuropathy and the severity of these symptoms vary from patient to patient. Major symptoms can include delayed motor (muscle) development (ability to turn over, stand, crawl, walk, etc.), muscle weakness, poor muscle tone (hypotonia), impaired muscle coordination, absence of reflexes (areflexia), difficulty in walking or crawling, and/or impaired ability to feel or move part of the body (mild distal palsy). In some infants, respiratory problems or difficulty in swallowing may occur. Abnormal microscopic changes in certain nerves such as sural nerves (located in the calf of the leg) can occur. Causes The exact cause of Congenital Hypomyelination Neuropathy is unknown. The cause of many disorders involving the myelin sheath (the protective sheath surrounding the nerves), such as Multiple Sclerosis, is unknown. A recurrent loss and repair of myelin causes Congenital Hypomyelination Neuropathy. Scientists do not yet know why the myelin disappears, nor do they know why it grows back. Some researchers believe, although this has not yet been established, that Congenital Hypomyelination Neuropathy may be a subtype of Dejerine- Sottas Disease which is inherited as an autosomal dominant trait. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In autosomal dominant disorders, a single abnormal gene, contributed by either parent, overrides the normal gene contributed by the other parent causing disease. Individuals with one affected parent have a 50% chance of inheriting the disorder. (For more information on Dejerine-Sottas Disease, see the Related Disorders section of this report). Other disorders characterized by the loss and repair of the myelin sheath may be autoimmune disorders. In autoimmune disorders the body's defenses against disease (e.g. antibodies or lymphocytes) attack healthy tissue for unknown reasons. Affected Population Congenital Hypomyelination Neuropathy is a rare disorder present at birth. It affects males and females in equal numbers. Related Disorders Dejerine-Sottas Disease is a hereditary neurological disorder which progressively affects muscle function. Peripheral nerves become enlarged and thickened causing an irregular progression of muscle weakness. Pain, weakness, numbness, and a tingling, prickling or burning sensation can occur in the patient's legs. Other symptoms include loss of heat sensitivity, absence of reflexes and atrophy of leg muscles. The hand and forearm muscles may become weak in later stages. Mild vision difficulties may also occur. (For more information on this disorder, choose "Dejerine-Sottas" as your search term in the Rare Disease Database). Guillain-Barre Syndrome (Acute Idiopathic Polyneuritis) occurs when the body's immune system (antibodies, lymphocytes) attacks the nerves, damaging the nerve's myelin and axon. Nerve signals are delayed and altered, causing weakness and paralysis of the muscles of the legs, arms, and other parts of the body along with abnormal sensations. When muscle nerves are damaged, the patient experiences aching and weak muscles, difficulty getting up from chairs or walking stairs, difficulty lifting objects, shortness of breath, and/or difficulty in swallowing. With proper treatment, most patients with Guillain-Barre Syndrome can expect to lead full and active lives. (For more information on this disorder, choose "Guillain" as your search term in the Rare Disease Database). Therapies: Standard Testing for Congenital Hypomyelination Neuropathy may include recording of electrical impulses produced by the muscles (electromyogram), as well as nerve and/or muscle biopsies. Treatment of Congenital Hypomyelination Neuropathy is symptomatic and supportive. Therapies: Investigational This disease entry is based upon medical information available through December 1990. 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 Congenital Hypomyelination Neuropathy, please contact: National Organization for Rare Disorders P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 NIH/National Institute of Neurological Disorders & Stroke (NINDS) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5751 (800) 352-9424 For genetic information and genetic counseling referrals, please contact: 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 (301) 652-5553 References THE MERCK MANUAL, Volume 1, 15th Ed.: Robert Berkow, M.D., ed.-in-chief; Merck, Sharp, and Dohme Laboratories, 1987. Pp. 1433-1434. A CASE OF CONGENITAL HYPOMYELINATION NEUROPATHY. CLINICAL, MORPHOLOGICAL, AND CHEMICAL STUDIES. W.R. Kennedy, et al.; Arch Neurol (Jun 1977; issue 34 (6)). Pp. 337-345. CONGENITAL HYPOMYELINATION NEUROPATHY IN A NEWBORN. S. Hakamada, et al.; Neuropediatrics (Aug 1983; issue 14 (3)). Pp. 182-183. CONGENITAL HYPOMYELINATION POLYNEUROPATHY. PATHOLOGICAL FINDINGS COMPARED WITH POLYNEUROPATHIES STARTING LATER IN LIFE. F. Guzzetta, et al.; Brain (Jun 1982; issue 105 (Pt 2)). Pp. 395-416. TWO CASES OF CONGENITAL HYPOMYELINATION NEUROPATHY. N. Tachi, et al.; Brain Dev (1984; issue 6 (6)). Pp. 560-565.