$Unique_ID{BRK04092} $Pretitle{} $Title{Pelizaeus-Merzbacher Brain Sclerosis} $Subject{Pelizaeus-Merzbacher Brain Sclerosis Diffuse Familial Brain Sclerosis Aplasia, Axialis Extracorticales Congenita Sudanophilic Leukodystrophy Pelizaeus-Merzbacher Disease} $Volume{} $Log{} Copyright (C) 1986, 1987, 1990 National Organization for Rare Disorders, Inc. 158: Pelizaeus-Merzbacher Brain Sclerosis ** IMPORTANT ** It is possible that the main title of the article (Pelizaeus-Merzbacher Brain Sclerosis) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms Diffuse Familial Brain Sclerosis Aplasia, Axialis Extracorticales Congenita Sudanophilic Leukodystrophy Pelizaeus-Merzbacher Disease 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. Pelizaeus-Merzbacher Brain Sclerosis is a progressive, degenerative central nervous system disease in which coordination, motor abilities, and intellectual function deteriorate. It often progresses rapidly, although some patients have lived to old age. The disorder almost always occurs in males. Symptoms Evidence of Pelizaeus-Merzbacher Brain Sclerosis usually appears in early infancy, although onset is later in one form. The child fails to develop normal control of head movements and grows slowly. The eyes wander aimlessly or in circular movements. Later symptoms include tremor, various involuntary movements, grimacing, weakness, unsteady gait, and muscle contractures. In cases with later onset, speech usually deteriorates. As time progresses, legs and then the arms can become spastic, and mental functions deteriorate. Some patients experience convulsions. Skeletal deformation may result from abnormal muscular stresses on bone. Pathologic changes in the brain consist of destruction of the myelin sheath (a kind of insulation) surrounding the axons of the nerve cells (the white matter of the brain). These changes occur in subcortical parts of the cerebrum, the cerebellum, and the brainstem. Breakdown products of myelin also accumulate in the brain. These stain characteristically. Causes The reasons for the degeneration of the white matter of the brain are not understood. Pelizaeus-Merzbacher Brain Sclerosis is hereditary. Infantile forms are either autosomal recessive or X-linked. 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 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. X-linked recessive disorders are conditions which are coded on the X chromosome. Females have two X chromosomes, but males have one X chromosome and one Y chromosome. Therefore in females, disease traits on the X chromosome can be masked by the normal gene on the other X chromosome. Since males have only one X chromosome, if they inherit a gene for a disease present on the X, it will be expressed. Men with X-linked disorders transmit the gene to all their daughters, who are carriers, but never to their sons. Women who are carriers of an X-linked disorder have a fifty percent risk of transmitting the carrier condition to their daughters, and a fifty percent risk of transmitting the disease to their sons. A form with adult onset is autosomal dominant. 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. Affected Population One form of Pelizaeus-Merzbacher Brain Sclerosis affects male infants. Other forms affect infants or adults of both sexes. Related Disorders Pelizaeus-Merzbacher Brain Sclerosis belongs to a group of degenerative brain diseases known as leukodystrophies. These are characterized by destruction of the white matter of the brain, and include such diseases as Krabbe's, Schilder's, Adrenoleukodystrophy, and several others. Therapies: Standard Treatment for Pelizaeus-Merzbacher Brain Sclerosis is symptomatic. Supportive care, including emotional support for family members, is recommended as needed. Therapies: Investigational Current research is directed toward the identification of the gene that causes Pelizaeus-Merzbacher Brain Sclerosis. When the gene is located, scientists may be able to determine the exact cause of the symptoms, which will hopefully lead to development of new treatments for this disease. This disease entry is based upon medical information available through January 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 Pelizaeus-Merzbacher Brain Sclerosis, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 United Leukodystrophy Foundation 2304 Highland Drive Sycamore, IL 60178 (815) 895-3211 (800) 728-5483 NIH/National Institute of Neurological Disorders & Stroke (NINDS) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5751 (800) 352-9424 International Tremor Foundation 360 W. Superior St. Chicago, IL 60610 (312) 664-2344 Research Trust for Metabolic Diseases in Children Golden Gates Lodge, Weston Rd. Crewe CW1 1XN, England Telephone: (0270) 250244 Association Europeenne contre les Leucodystrophies 7 Rue Pasteur 54000 NANCY France References CECIL TEXTBOOK OF MEDICINE, 18th ed.: James B. Wyngaarden, and Lloyd H. Smith, Jr., Eds.: W. B. Saunders Co., 1988. P. 2216.