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$Unique_ID{BRK04070}
$Pretitle{}
$Title{Osteogenesis Imperfecta}
$Subject{Osteogenesis Imperfecta Brittle Bone Disease Ekman-Lobstein Disease
Lobstein Disease (Type I) OI Osteopathyrosis Vrolik Disease (Type II)
Osteogenesis Imperfecta Congenita also known as IO Congenita Osteoporosis
Vitamin Resistant Rickets Achondroplasia Osteogenesis Imperfecta Tarda also
knows as IO Tarda}
$Volume{}
$Log{}

Copyright (C) 1984, 1985, 1986, 1987, 1988, 1990, 1992 National
Organization for Rare Disorders, Inc.

16:
Osteogenesis Imperfecta

** IMPORTANT **
It is possible that the main title of the article (Osteogenesis)
Imperfecta is not the name you expected.  Please check the SYNONYMS listing
to find the alternate name and disorder subdivisions covered by this article.

Synonyms

     Brittle Bone Disease
     Ekman-Lobstein Disease
     Lobstein Disease (Type I)
     OI
     Osteopathyrosis
     Vrolik Disease (Type II)

DISORDER SUBDIVISIONS:

     Osteogenesis Imperfecta Congenita also known as IO Congenita
     Osteogenesis Imperfecta Tarda also knows as IO Tarda

Information on the following diseases can be found in the Related
Disorders section of this report:

     Osteoporosis
     Vitamin Resistant Rickets
     Achondroplasia

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.


Osteogenesis Imperfecta is characterized by unusually fragile bones that
break or fracture easily.  There are generally considered to be 4 types of
this disorder, some with subtypes.  The congenital form, type II, is the most
severe; affected infants are either stillborn or die shortly after birth of
respiratory insufficiency.  Other forms of Osteogenesis Imperfecta range from
mild to severe.

Symptoms

Osteogenesis Imperfecta is characterized by bone fractures, especially of the
long bones of the legs, even after minimal trauma.

Type I Osteogenesis Imperfecta is characterized by blue coloration to the
membrane covering the rear portion of the eye (sclera).  Generally there is
little or no bone deformity and normal stature.  There is hearing loss in
about 50 percent of type I Osteogenesis Imperfecta patients.

Type II Osteogenesis Imperfecta is lethal in the newborn period.  Infants
are born with multiple fractures as well as compressed fractures.  Long bone
deformities are generally present.

Patients with type III Osteogenesis Imperfecta have short stature and
only a variable bluish color to the sclera of the eye.  Hearing loss and
dental problems are common.  Deformities of the bones tends to be
progressive.

Patients with type IV Osteogenesis Imperfecta have normal sclera in the
eyes, mild bone deformity, and variable short stature.  Abnormal development
of dentin (a major component of the teeth, surrounding the pulp and covered
with enamel) is also common (dentinogenesis).  Hearing loss is rare.

Causes

Osteogenesis Imperfecta is commonly inherited as an autosomal dominant gene,
but a recessive pattern has been identified in a few patients.  More that 50
variants (mutations) in the genes that encode the chains of type I collagen
have been identified.  The exact nature of the mutation determines the type
of Osteogenesis Imperfecta and the symptoms that are present.

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

Osteogenesis Imperfecta occurs in 1:20,000 to 1:50,000 births in the United
States.

Related Disorders

Symptoms of the following disorders can be similar to Osteogenesis
Imperfecta.  Comparisons may be useful for a differential diagnosis:

Osteoporosis is a disorder of the bones that is characterized by a
decrease in the density and weight of bones (rarefaction).  This can lead to
fractures after even minor trauma.  Osteoporosis occurs frequently in post-
menopausal women or people that are immobile or sedentary.  This disorder may
cause pain, especially in the lower back, and a variety of deformities.

Vitamin D Deficiency Rickets, which appears during infancy and childhood,
is a disorder that is characterized by abnormal bone formation.  Vitamin D is
needed for the metabolism of calcium and phosphorus, which then affects the
depositing of calcium in the bones.  The major symptoms include restlessness
and a lack of sleep, slow growth and there is a delay in crawling, sitting,
or walking.  If the disorder remains untreated, the ends of the long bones
may become enlarged and the legs may bow.  (For more information on this
disorder, choose "Rickets, Vitamin D Deficiency" as your search term in the
Rare Disease Database).

Achondroplasia is a rare inherited disorder that results in short stature
(dwarfism) due to the impairment of bone formation.  Head and facial
abnormalities are also associated with the disorder.   Generally the
characteristics include an unusually large forehead, short arms and legs, an
elongated trunk, and hands that are short and broad.  Water on the brain
(hydrocephalus) may also be present and the compression of the brain stem may
be fatal.  (For more information on this disorder, choose "Achondroplasia" as
your search term in the Rare Disease Database).

Therapies:  Standard

The treatment for Osteogenesis Imperfecta is symptomatic and supportive.  In
the past treatments have included diets intended to promote calcium and
magnesium deposition to the bone, and hormonal treatments with gonadotropins,
growth hormone, and calcitonin.  These have proven ineffective, and the
latter in particular has had serious side effects on children.

Exercise and physical therapy programs have proven of great value in
strengthening muscles, increasing weight-bearing capacity, and reducing the
tendency to fracture.  Hydrotherapy (physical therapy in the water) has been
particularly helpful.  Various aids are also in use.  "Rodding" is a standard
procedure in which metal rods are surgically placed in the long bones to
prevent fractures.  Plastic braces are replacing plaster casts as protective
devices because they permit greater freedom of movement and can be used in
water.  Inflatable suits can provide added protection, especially to very
young children.

Genetic counseling may be of benefit for patients and their families.
Other treatment is symptomatic and supportive.

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.

Resources

For more information on Osteogenesis Imperfecta, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     Osteogenesis Imperfecta Foundation
     5000 W. Laurel St., Suite 210
     Tampa, FL 33607-3836
     [phone]

     The National Arthritis and Musculoskeletal and Skin Diseases Information
     Clearinghouse
     Box AMS
     Bethesda, MD  20892
     [phone]

     Clinic:  Dr. Michael P. White, Medical Director
     Metabolic Research Unit
     Shriners' Hospital for Crippled Children
     2001 Lindbergh Blvd.
     Saint Louis, MO  63131

For genetic information and genetic counseling referrals, please contact:

     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

THE MERCK MANUAL 15th ed:  R. Berkow, et al:  eds; Merck, Sharp & Dohme
Research Laboratories, 1987.  Pp. 1948, 2104.

CECIL TEXTBOOK OF MEDICINE, 18th ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Eds.:  W.B. Saunders Co., 1988.  Pp. 1180-1, 1982.

MENDELIAN INHERITANCE IN MAN, 10th Ed.:  Victor A. McKusick, Editor:
Johns Hopkins University Press, 1992.  Pp. 1611-1614.

CECIL TEXTBOOK OF MEDICINE, 19th Ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Editors; W.B. Saunders Co., 1990.  Pp. 1124-1125.

BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief;
Blackwell Scientific Publications, 1990.  Pp. 1321-1323.

OSTEOGENESIS IMPERFECTA, P.H. Byers and R.D. Steiner; Annual Review
Medicine (1992; 43): Pp. 269-282.

OSTEOGENESIS IMPERFECTA, J.M. Gertner and L. Root; Orthop Clin North
America (Jan. 1990; 21(1)): Pp. 151-162.