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$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
     [phone]

     Metatrophic Dysplasia Helpline
     3393 Geneva Dr.
     Santa Clara, CA  95051
     [phone]

     The Magic Foundation
     1327 N. Harlem Ave.
     Oak Park, IL  60302
     [phone]

     Human Growth Foundation (HGF)
     7777 Leesburg Pike
     P.O. Box 3090
     Falls Church, VA  22043
     [phone]
     [phone]

     NIH/National Institute of Child Health and Human Development
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]

     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
     [phone]

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     [phone]

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.