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$Unique_ID{BRK03412}
$Pretitle{}
$Title{Achondrogenesis}
$Subject{Achondrogenesis Neonatal Dwarfism Hypochondrogenesis Chondrogenesis
Imperfecta Lethal Neonatal Dwarfism Lethal Osteochondrodysplasia
Achondrogenesis Type I Houston-Harris Type Achondrogenesis Type IA
Parenti-Fraccaro Type Achondrogenesis Type IB Langer-Saldino Type
Achondrogenesis Type II Grebe Type Kniest Syndrome Camptomelic Dysplasia
Thanatophoric Dysplasia Short Rib Syndrome}
$Volume{}
$Log{}

Copyright (C) 1992 National Organization for Rare Disorders, Inc.

876:
Achondrogenesis

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

Synonyms

     Neonatal Dwarfism
     Hypochondrogenesis
     Chondrogenesis Imperfecta
     Lethal Neonatal Dwarfism
     Lethal Osteochondrodysplasia

Disorder Subdivisions:

     Achondrogenesis, Type I Houston-Harris Type
     Achondrogenesis, Type IA Parenti-Fraccaro Type
     Achondrogenesis, Type IB Langer-Saldino Type
     Achondrogenesis, Type II Grebe Type

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

     Kniest Syndrome
     Camptomelic Dysplasia
     Thanatophoric Dysplasia
     Short Rib 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.


Achondrogenesis is a very rare disorder that is inherited as an autosomal
recessive genetic trait.  Major symptoms include extreme short limbed
dwarfism, lack of development of ribs and other major bone formation.  The
head may be either soft or enlarged depending on the type of Achondrogenesis
involved.  The disorder is often fatal either in utero (in the womb) or
shortly after birth.

Symptoms

Achondrogenesis is characterized by premature birth, accumulation of fluid in
the body (fetal hydrops), either a soft or abnormally large head, short neck
and trunk.  There are extremely short limbs and lack of proper development of
the ribs, vertebra and other bones of the skeleton.  The abdomen is very
prominent.  The growth plate is markedly abnormal.  The disorder is lethal
either in utero or shortly after birth.  Other abnormalities that may occur
are:  cleft palate, corneal clouding, ear deformities and underdeveloped
testicles and rectum.

Type I Achondrogenesis, Houston Harris Type, is characterized by
prematurity, accumulation of fluid in the body, and an excess of amniotic
fluid in the womb before birth (polyhydramnios).  The head may be soft but
of a normal size.  The infant may have a very short limbs, lack of
development of the bones of the spine, and an extremely short neck.  The ribs
may show multiple fractures and be very short as are the other bones of the
body.  The infant is usually stillborn or dies very shortly after birth.

Achondrogenesis Type IA Parenti-Fraccaro Type, is another form of
Dwarfism.  It is the same as the Houston Harris Type in that the baby's head
is soft but of normal size.  The child is born prematurely and there is an
abnormal accumulation of fluid in the body.  The baby's bones in the spine,
arms and legs are not properly developed.  The ribs are also very short but
they do not show fractures as do the ribs of the infants with Type I
Achondrogenesis.  As with Type I Achondrogenesis, the infants are either
stillborn or die soon after birth.

Type IB Achondrogenesis, Langer-Saldino Type, has the same features as
the previous forms of Achondrogenesis, however, it is characterized by an
abnormally large head.  The size of the infant's head makes delivery very
difficult so extreme care is necessary in order to prevent damage to the
mother.  This form of dwarfism may result in stillborn infants or in less
severe cases the infant may survive for weeks or months.  This form of
Achondrogenesis may also be inherited through autosomal dominant genetic
patterns as well as autosomal recessive genetic inheritance.

Type II Achondrogenesis, Grebe Chondrodysplasia, is characterized by very
shortened limbs, a normal head and chest area.  There may be absent or extra
fingers or toes, or these digits may be very small.  The hands and feet are
extremely short and stubby.  This Type of Achondrogenesis does not result in
death as the chest area is not abnormally small and breathing is not
constricted.

Causes

Achondrogenesis is caused by autosomal recessive inheritance in most
instances.  However, in the case of Type IB, Langer-Saldino Type, there may
be rare cases of autosomal dominant patterns of inheritance.

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 from 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

Achondrogenesis is a very rare form of dwarfism that affects males and females
in equal numbers.  The Grebe Type is usually found in a highly inbred
Brazilian population and in Miao Chinese.  There is also a form that affects
certain people of German heritage.

Related Disorders

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

Kniest Syndrome is characterized by extremely short stature with a
shortened, barrel-shaped chest.  The face is flat with bulging eyes.  There
may also be a flat nasal bridge, cleft palate and excessive ear infections.
The child may also be nearsighted which may lead to retinal detachment.  The
arms and legs are very short with bowing.  There is usually enlargement of
the joints causing pain and stiffness.  Hernias, loss of hearing and a
collapsing trachea may also occur.

Camptomelic Dysplasia is another form of growth deficiency.  The infant
is born with an enlarged head, flat face and nasal bridge, cleft palate and
deformed ears.  There are short flat vertebrae, small rib cage and incomplete
development of bones in the arms and legs.  Often there is a lack of
development of sexual characteristics.  There is central nervous system
problems and failure to thrive.  If the infant survives the newborn period
there will be feeding and breathing problems.

Thanatophoric Dysplasia is another form of dwarfism.  It is characterized
by enlarged head, shortened bones in the arms and legs, small, short ribs and
flattened vertebrae.  There is an abnormally large amount of amniotic fluid
and very little fetal movement.

Short Rib Syndrome is a form of short limb dwarfism.  The infant has
cleft lip and palate, deformed ears, narrow chest with short ribs.  The
kidneys are often deformed as are the sex organs.  There may be brain
malformations and an absence of a gallbladder.  These infants often die soon
after birth as a result of insufficient lung development.

Therapies:  Standard

Ultrasound of the mother in the third trimester can often warn of the
condition of the fetus.  Treatment of the condition is to maintain the
mothers health.  Genetic counseling may be of benefit for families.  Other
treatment is symptomatic and supportive.

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 birth defects in the future.

Therapies:  Investigational

The Titanium Rib Project is underway to implant expandable ribs in patients
with disorders involving missing, underdeveloped or otherwise malformed rib
cages, ribs or chest walls.  Absent areas due to surgery or birth defects,
fused ribs or hypoplastic chests may be improved using the titanium ribs
which can be expanded as the child grows.  Interested persons may contact:

     Dr. Robert Campbell
     Santa Rosa Children's Hospital
     519 W. Houwton St.
     San Antonio, TX  78207-3198
     [phone]

This disease entry is based upon medical information available through
September 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 Achondrogenesis, please contact:

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

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

     International Center for Skeletal Dysplasia
     St. Joseph Hospital
     7620 York Road
     Towson, MD 21204
     [phone]

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

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

     Parents of Dwarfed Children
     11524 Colt Terrace
     Silver Spring, MD 20902

     Little People of America
     P.O. Box 633
     San Bruno, CA  94066
     [phone]

     Short Stature Foundation
     17200 Jamboree Rd., Suite J
     Irvine, CA  92714-5828
     [phone]
     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
     [phone]

References

MENDELIAN INHERITANCE IN MAN, 9th Ed.:  Victor A. McKusick, Editor:  Johns
Hopkins University Press, 1990.  Pp. 994-996.

SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th Ed.:  Kenneth L.
Jones, M.D., Editor; W.B. Saunders Co., 1988.  Pp. 281, 286, 290, 296, 312.

BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-in-Chief,
Blackwell Scientific Publications, 1990.  Pp. 8, 9, 10, 813.

ACHONDROGENESIS TYPE II (LANGER-SALDINO) IN ASSOCIATION WITH JUGULAR
LYMPHATIC OBSTRUCTION SEQUENCE., Wenstrom, Kd, et al.; Prenat Diagn, July,
1989, (issue 9 (7)).  Pp. 527-532.

TYPE II ACHONDROGENESIS-HYPOCHONDROGENESIS:  MORPHOLOGIC AND
IMMUNOHISTOLOGIC STUDIES., Godfrey, M., et al.; Am J Hum Genet, December,
1988 (issue 43 (6)).  Pp. 894-904.

ACHONDROGENESIS TYPE I:  DELINEATION OF FURTHER HETEROGENEITY AND
IDENTIFICATION OF TWO DISTINCT SUBGROUPS., Borochowitz, Z., et al.; J
Pediatr, January, 1988 (issue 112 (1)).  Pp. 23-31.