$Unique_ID{BRK03909} $Pretitle{} $Title{Kniest Syndrome} $Subject{Kniest Syndrome Syndrome de Kniest Swiss Cheese Cartilage Syndrome Morquio Syndrome Metatropic Dwarfism Syndrome } $Volume{} $Log{} Copyright (C) 1990 National Organization for Rare Disorders, Inc. 755: Kniest Syndrome ** IMPORTANT ** It is possible that the main title of the article (Kniest Syndrome) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms Syndrome de Kniest Swiss Cheese Cartilage Syndrome Information on the following diseases can be found in the Related Disorders section of this report: Morquio Syndrome Metatropic Dwarfism 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. Kniest Syndrome is a 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. Intellect is usually normal in people with this syndrome. Symptoms People with Kniest Syndrome are known to have disproportionately short stature with a short, barrel-shaped chest, short deformed arms and legs, and a relatively long trunk. Later in life, short trunk dwarfism develops due to curvature of the spine and enlargement of the joints. The head and face of people with Kniest Syndrome is usually flat with protruding eyes, and a low nasal bridge. A cleft palate with speech impairment and frequent ear infections also occur. Involvement of the eyes may include nearsightedness (myopia) that can progress to retinal detachment and cataracts. Dislocated eye lenses, drooping of the eyelids (blepharoptosis), possible blindness with disease of the optic nerve, involvement of the spine or brain, and glaucoma may also occur. As the person matures, the joints may become enlarged causing limited movement and pain. Limbs are short, often bowed, and there may be irregularities of the ends of the long bones (epiphyses). Contracted hips may cause walking difficulties and there may be a congenital flattening of the vertebrae and a hump of the spine. Hernias of the groin (inguinal) and navel (umbilical), a small pelvis, short collarbones, slowed motor development and hearing loss may also occur. In some cases of Kniest Syndrome there may be an excessive excretion of keratan sulfate in the urine, while a softening of the connective tissue in the trachea (tracheomalacia) causing a "Swiss-cheese" appearance has also been known to develop. People with this disorder usually have normal intelligence. Causes The exact cause of Kniest Syndrome is not known. In some cases it may be inherited as an autosomal dominant trait. Some scientists believe that some cases of this disorder may be due to a sporadic genetic mutation because no other family members have symptoms of the syndrome. 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 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. Affected Population Kniest Syndrome is a rare disorder that affects males and females in equal numbers. Related Disorders Symptoms of the following disorders can be similar to those of Kniest Syndrome. Comparisons may be useful for a differential diagnosis: 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. Surgery to stabilize the upper cervical spine, usually by spinal fusion, can prevent severe paralysis. There may also be enlargement of the liver, curvature of the spine (thoracic kyphoscoliosis), a back flow of blood from the aortic valve of the heart into the left ventricle of the heart (aortic regurgitation), as well as loss of hearing. (For more information on this disorder, choose "Morquio" as your search term in the Rare Disease Database). Metatropic Dwarfism Syndrome is a rare genetic disorder characterized by extremely small stature, with short and deformed arms and legs. Other characteristics of this disorder are a narrow thorax with short ribs, prominent joints with restricted mobility of the knees and hips, and unusual increased extension of the finger joints. There is also an unusually long torso, which later develops into short trunk dwarfism due to curvature of the spine and enlargement of the joints. This rare disorder is often recognized at birth because the spinal deformities tend to be severe during infancy. (For information about other forms of dwarfism choose "Dwarf" as your search term in the Rare Disease Database.) Therapies: Standard Treatment of Kniest Syndrome usually consists of stabilization of lax joints, surgery to prevent contractures, and repair of retinal detachments and cleft palate. Genetic counseling may be of benefit for patients and their families. Other treatment is symptomatic and supportive. Therapies: Investigational This disease entry is based upon medical information available through July 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 Kniest Syndrome, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 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 Little People of America P.O. Box 633 San Bruno, CA 94066 (415) 589-0695 Short Stature Foundation 17200 Jamboree Rd., Suite J Irvine, CA 92714-5828 (714) 474-4554 800-24 DWARF 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, 7th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 492 SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION. 4th Ed.: Kenneth Jones, M.D.; Saunders, 1988, Pp. 312, 313-314. A DISTINCT CHONDRODYSPLASIA RESEMBLING KNIEST DYSOLASIA: CLINICAL, ROENTGENOGRAPHIC, HISTOLOGIC, AND ULTRASTRUCTURAL FINDINGS. S. Sconyers, et al.; J PEDIATR (December 1983, issue 103 (6)). Pp. 898-904. KNIEST DYSPLASIA IS CHARACTERIZED BY AN APPARENT ABNORMAL PROCESSING OF THE C-PROPEPTIDE OF TYPE II CARTILAGE COLLAGEN RESULTING IN IMPERFECT ASSEMBLY. A. Poole, et al.; J CLIN INVEST (February 1988, issue 81 (2)). Pp. 579-589. THE OCULAR FINDINGS IN KNIEST DYSPLASIA. I. Maumenee, et al.; AM J OPTHALMOL (July 15, 1985, issue 100 (1)). Pp. 155-160. OCULAR MANIFESTATIONS IN KNIEST SYNDROME, SMITH-LEMLI-OPITZ SYNDROME, HALLERMANN-STREIFF-FRANCOIS SYNDROME, RUBENSTEIN-TAYBI SYNDROME AND MEDIAN CLEFT SYNDROME. A. Bardelli, et al.; OPHTHALMIC PAEDIATR GENET, (August 1985, issue 6 (1-2)). Pp. 343-347.