$Unique_ID{BRK04008} $Pretitle{} $Title{Morquio Syndrome} $Subject{Morquio Syndrome Mucopolysaccharidosis IV MPS IV Morquio Disease Morquio Syndrome A Galactosamine-6-Sulfatase Deficiency Morquio-Brailsford Syndrome Osteochondrodystrophy Deformans Chondroosteodystrophy Morquio Syndrome B Beta-Galactosidase Deficiency Morquio Syndrome} $Volume{} $Log{} Copyright (C) 1986, 1987, 1988, 1990 National Organization for Rare Disorders, Inc. 299: Morquio Syndrome ** IMPORTANT ** It is possible the main title of the article (Morquio Syndrome) is not the name you expected. Please check the SYNONYMS listing to find the alternate names and disorder subdivisions covered by this article. Synonyms Mucopolysaccharidosis IV MPS IV Morquio Disease DISORDER SUBDIVISIONS Morquio Syndrome A Galactosamine-6-Sulfatase Deficiency Morquio-Brailsford Syndrome Osteochondrodystrophy Deformans Chondroosteodystrophy Morquio Syndrome B Beta-Galactosidase Deficiency 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. Mucopolysaccharidoses (MPS Disorders) are a group of rare genetic disorders caused by the deficiency of one of ten specific lysosomal enzymes, resulting in an inability to metabolize complex carbohydrates (mucopolysaccharides) into simpler molecules. The accumulation of these large, undegraded mucopolysaccharides in the cells of the body causes a number of physical symptoms and abnormalities. Morquio Syndrome (MPS IV) exists in 2 forms: Morquio Syndromes A and B are due to a deficiency in the enzyme N-acetyl- galactosamine-6-sulfatase and beta-galactosidase, respectively. Deficiency of either enzyme leads to an accumulation of keratan sulfate and bony abnormalities of the head, chest, hands, knees and spine may occur as a result of this metabolic defect, with preservation of intellect. The skeletal abnormalities in MPS IV-B are usually milder than in MPS IV-A. Symptoms Developmental abnormalities occurring in Morquio Syndrome may be detected as early as 18 months to 2 years of age. The skeletal abnormalities are milder in Morquio Syndrome A than in Morquio Syndrome B. These may include an enlarged head, a broad mouth, prominent cheekbones, an unusually small nose, widely spaced and thinly enameled teeth, and widely separated eyes with corneal clouding. Later, patients tend to develop abnormally short necks, short barrel chests, disproportionately long arms, enlarged and possibly hyperextensible wrists, stubby hands and "knock knees". Together with the misaligned knees and knobby joints, the child may be "pigeon-toed", causing a wobbly gait. The joint laxity and bony abnormalities of the spine can result in life-threatening spinal cord compression. Surgery to stabilize the upper cervical spine, usually by spinal fusion, can be lifesaving. There may also be enlargement of the liver, curvature of the spine (thoracic kyphoscoliosis), flow of blood from the aorta back into the left ventricle of the heart (aortic regurgitation), and hearing loss. Causes Morquio Disease is an autosomal recessive hereditary disorder in which a deficiency of galactosamine 6 sulfatase in type A of the disorder, and a deficiency of beta-galactosidase in type B, leads to an accumulation of keratan sulfate in the urine. (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.) Affected Population Morquio Syndrome affects males as often as females. The disorder occurs in less than 1 in 100,000 live births except in the French-Canadian population where it is known to be the most common type of mucopolysaccharidoses. Related Disorders There are many types of Mucopolysaccharidosis. Information about each of these types of MPS can be located in the Rare Disease Database. (For more information, choose "MPS Disorders" as your search term in the Rare Disease Database.) DiFerrante syndrome (mucopolysaccharidosis VIII) is a disorder described in a single patient with clinical and biochemical features of Morquio and Sanfilippo syndromes. The disorder had been reported to be due to a deficiency of glucosamine-6-sulfate sulfatase. Subsequently, this disorder was called MPS VIII (DiFerrante syndrome). Dr. DiFerrante later found that the enzyme was normal in his patient, and the disorder had been misdiagnosed. Therefore, DiFerrante syndrome is not a valid medical disorder. The Mucolipidoses are a family of similar disorders, producing symptoms very much like those of the Mucopolysaccharidoses. I-cell disease, or Mucolipidosis Type II, resembles Hurler syndrome and the two disorders are very difficult to distinguish. I-cell disease has similar physical and mental deterioration as MPS I, but usually occurs earlier and is more severe. I-cell diseases is characterized by diffused deficiency of lysosomal enzymes with the cell and is not associated with excretion of mucopolysaccharides in the urine. Pseudo-Hurler Polydystrophy (Mucolipidosis III) is also transmitted by autosomal inheritance, but it is characterized by a deficiency of multiple lysosomal enzymes needed to break down mucopolysaccharides. ML III affects males more often than females, and can be identified by such symptoms as claw-like hands, somewhat coarse facial features, dwarfism and pain in the hands. Intelligence tends to be normal in most patients, but mild mental retardation is sometimes present. Ganglioside Sialidase Deficiency (Mucolipidosis IV) is a disorder of unknown cause characterized by early clouding of the cornea, mild to moderate mental retardation and enlargement of spleen and liver. (For more information on the Mucolipidoses, choose "ML Disorder" as your search term in the Rare Disease Database.) Therapies: Standard Treatment of Morquio Syndrome is symptomatic and supportive. Physical therapy and special educational services may be helpful. Genetic counseling may be helpful to the parents of patients with Morquio Syndrome. Prenatal diagnosis is now possible for this disorder. Therapies: Investigational Since prenatal diagnosis is now possible through amniocentesis and sampling of a tissue layer in the embryo (chorionic villus sampling), new treatments aimed at checking early development of Morquio Syndrome are now under study. One method involves replacing defective enzymes via enzyme replacement therapy and/or bone marrow transplants. Scientific study of gene replacement in animal models raises the hope that gene replacement may someday be made available to people with genetic disorders such as Morquio Syndrome. The Mayo Clinic is investigating the use of Alpha Interferon as a treatment for Morquio Syndrome. For more information, physicians can contact: Morie A. Gertz, M.D. Dept. of Hematology & Internal Medicine Mayo Clinic Rochester, MN 55905 (507) 284-2511 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 Morquio Syndrome, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 MPS (Mucopolysaccharidoses) Research Funding Center, Inc. 1215 Maxfield Road Hartland, MI 48029 (313) 363-4412 National MPS Society 17 Kramer Street Hicksville, NY 11801 (516) 931-6338 National Digestive Diseases Information Clearinghouse Box NDDIC Bethesda, MD 20892 (301) 468-6344 Society of Mucopolysaccharide Diseases, Inc. 382 Parkway Blvd. Flin Flon, Manitoba, Canada R8A OK4 Society of MPS Diseases 30 Westwood Drive Little Chalfont, Bucks, England For information on genetics 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 MPS Society Brochure. BIRTH DEFECTS COMPENDIUM, 2nd ed.: Daniel Bergsma, ed: March of Dimes, 1979. P. 732. MENDELIAN INHERITANCE IN MAN, 6th ed.: Victor A McKusick; Johns Hopkins University Press, 1983. Pp. 840-841.