$Unique_ID{BRK04001} $Pretitle{} $Title{Metatropic Dysplasia I} $Subject{Metatropic Dysplasia I Chondrodystrophy Hyperplastic Form Dwarfism Metatropic Metatropic Dwarfism Metatropic Dwarfism Syndrome Metatropic Dysplasia Kniest Syndrome Morquio Syndrome } $Volume{} $Log{} Copyright (C) 1992 National Organization for Rare Disorders, Inc. 870: Metatropic Dysplasia I ** IMPORTANT ** It is possible that the main title of the article (Metatropic Dysplasia I) is not the name you expected. Please check the SYNONYMS listing to find the alternate name and disorder subdivisions covered by this article. Synonyms Chondrodystrophy, Hyperplastic Form Dwarfism, Metatropic Metatropic Dwarfism Metatropic Dwarfism Syndrome Metatropic Dysplasia Information on the following diseases can be found in the Related Disorders section of this report: Kniest Syndrome Morquio 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. Metatropic Dysplasia I is a rare genetic disorder characterized by extremely small stature, with short arms and legs. Other characteristics of this disorder are a narrow thorax, short ribs, and kyphoscoliosis which develops into short trunk dwarfism. Symptoms Metatropic Dysplasia I is characterized by abnormal skeletal development. Patients with this disorder typically have short ribs, short deformed arms and legs, kyphoscoliosis (abnormal curvature of the spine) and extremely short stature. A long narrow thorax, bulging joints with limited mobility of the knees and hips, and unusual increased extension of the finger joints are typical features. An unusually long torso, which later develops into short trunk dwarfism due to curvature of the spine, is an early feature of Metatropic Dysplasia I. The spine develops a forward hump-like curvature causing a humpback. X-rays show growth insufficiency of the vertebral column with flattening of vertebrae and often growth insufficiency in the arm and leg bones at the hip and shoulder joints. A crescent-like iliac causing a hump at the end of the spine is also apparent. Causes Metatropic Dysplasia I can be inherited as an autosomal dominant or autosomal recessive 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 dominant disorders a single copy of the disease gene (received from either the mother or father) will be expressed "dominating" the other normal gene and resulting in the appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is fifty percent 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 for the same trait 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 not show 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. Affected Population Metatropic Dysplasia I is a very rare disorder that affects males and females in equal numbers. Related Disorders Symptoms of the following disorders can be similar to those of Metatropic Dysplasia I. Comparisons may be useful for a differential diagnosis: Kniest Syndrome is a rare type of dwarfism that is characterized by unusually short arms and legs, a round face with hollow or depressed areas, swelling and stiffness of the joints, and a stiff drawing up (contractures) of the fingers. A cleft palate, curvature of the spine (scoliosis), vision and hearing problems may also occur. (For more information on this disorder, choose "Kniest" as your search term in the Rare Disease Database). Morquio Syndrome is a metabolic disorder characterized by an accumulation of keratan sulfate. Bony abnormalities of the head, chest, hands, knees, and spine may occur as a result of this defect. Intelligence is usually normal. The bony abnormalities of the spine can result in spinal cord compression. There also may be enlargement of the liver, curvature of the spine, a back flow of blood from the aortic valve of the heart into the left ventricle of the heart, as well as a loss of hearing. (For more information on this disorder, choose "Morquio" as your search term in the Rare Disease Database). Therapies: Standard Treatment of Metatropic Dysplasia I is symptomatic and supportive. When partial dislocation of the segments of the spinal column at the top of the spine (cervical vertebrae) is present, the joint between the two vertebrae can be fused together. This procedure should be done in order to prevent damage to the cervical part of the spinal cord. Genetic counseling may be of benefit for patients and their families. Therapies: Investigational Research on birth defects and their causes is ongoing. The National Institutes of Health (NIH) is sponsoring the Human Genome Project which is aimed at mapping every gene in the human body and learning why they sometimes malfunction. It is hoped that this new knowledge will lead to prevention and treatment of genetic disorders in the future. This disease entry is based upon medical information available through April 1992. 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 Metatropic Dysplasia I, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 Metatrophic Dysplasia Helpline 3393 Geneva Dr. Santa Clara, CA 95051 (408) 244-6354 The Magic Foundation 1327 N. Harlem Ave. Oak Park, IL 60302 (708) 383-0808 Human Growth Foundation (HGF) 7777 Leesburg Pike P.O. Box 3090 Falls Church, VA 22043 (703) 883-1773 (800) 451-6434 NIH/National Institute of Child Health and Human Development 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5133 Parents of Dwarfed Children 11524 Colt Terr. Silver Spring, MD 20902 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 (301) 652-5553 References MENDELIAN INHERITANCE IN MAN, 9th Ed.: Victor A. McKusick, Editor: Johns Hopkins University Press, 1990. Pp. 1323. SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th Ed.: Kenneth L. Jones, M.D., Editor; W.B. Saunders Co., 1988. Pp. 318. BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief; Blackwell Scientific Publications, 1990. Pp. 1135-36. ODONTOID HYPOPLASIA WITH VERTEBRAL CERVICAL SUBLUXATION AND VENTRICULOMEGALY IN METATROPIC DYSPLASIA: M. Shohat, et al.; J Pediatr (February, 1989, issue 114(2)). Pp. 239-43.