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$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.