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$Unique_ID{BRK03738}
$Pretitle{}
$Title{FG Syndrome}
$Subject{FG Syndrome Opitz-Kaveggia Syndrome Townes-Brocks Syndrome VACTERL
Association REAR Syndrome}
$Volume{}
$Log{}

Copyright (C) 1991 National Organization for Rare Disorders, Inc.

827:
FG Syndrome

** IMPORTANT **
It is possible that the main title of the article (FG 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

     Opitz-Kaveggia Syndrome

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

     Townes-Brocks Syndrome
     VACTERL Association
     REAR 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.

FG Syndrome is an uncommon hereditary disorder which affects males.  The
presence and severity of symptoms vary from patient to patient.  Some females
may have certain physical characteristics related to FG Syndrome because they
are "carriers" of the trait, but they are not affected by the disorder
itself.

Males with FG Syndrome may have mental retardation, an absence of an anal
opening (imperforate anus) or an abnormally placed anus, constipation,
diminished muscle tone (hypotonia), a large head and certain other physical
characteristics.  Deafness may be present in some patients.  Individuals with
FG Syndrome seem to have a specific personality type and are often friendly,
outgoing, and hyperactive with a short attention span.

Symptoms

MALES WITH FG SYNDROME:

The presence and severity of symptoms in males with FG Syndrome vary from
patient to patient and may include mental retardation, heart defects, delayed
muscle system (motor) development, diminished muscle tone (hypotonia),
seizures, abnormally large brain (megalencephaly), eyelid abnormalities
(short palpebral fissures), constipation, muscle contraction of the joints
(multiple joint contractures), webbing of two or more fingers or toes
(syndactyly), vertebral defects of the spine, a dimple in the area right
above the tailbone (sacral dimple), or undescended testicles
(cryptorchidism).  The "soft spot" (anterior fontanel) of the baby's skull
may be larger than usual.  In some patients, there is an absence of an anal
opening (imperforate anus).  In others, abnormal placement of the anus may
occur.  The anus may be constricted or smaller than normal (anal stenosis).
There may be an abnormal opening located on the underside of the penis
(hypospadias).  Deafness (sensorineural) is present in some patients and may
be severe.

Individuals with FG Syndrome are often friendly, and outgoing.  They are
also hyperactive with a short attention span.  They may be easily frustrated
and prone to temper tantrums.

Physical characteristics can include a disproportionately large head (for
height), prominent forehead, cowlick (frontal hair upsweep), unusually wide-
set eyes (hypertelorism), a skin fold over the inner corner of the eye
(epicanthal folds), prominent lower lip, and small ears.  The cornea (of the
eye) may appear to be larger than normal.  The roof of the mouth (palate) may
be narrow, or may have a cleft.  Wrinkling of the facial skin is sometimes
present.  In some individuals, the upper lip is longer than average.  Thumbs
and big toes are usually broad.  Individuals with FG Syndrome often have
short stature.

Occasionally, skull abnormalities occur such as premature fusion of the
unjoined bones of a baby's skull (craniosynostosis), or an accumulation of
fluid in the brain (hydrocephalus), or absence of part of the brain known as
the corpus callosum.  (For more information, choose "hydrocephalus", or
"corpus callosum" as your search terms in the Rare Disease Database).
Rarely, intestinal abnormalities, heart defects or dilation of the urinary
tract may occur.

FEMALE "CARRIERS" OF THE FG SYNDROME TRAIT:

FG Syndrome is an X-linked trait which is passed from mother to son (see
"Causes" section).  To date mothers of males with FG Syndrome have shown
normal intelligence.  Some may have the following physical characteristics:
a broad forehead, cowlick, excess skin over the inner corners of the eyes
(epicanthal folds), unusually wide-set eyes (hypertelorism), or abnormal
placement of the anus.  In some females, the upper lip is longer than
average.

Causes

FG Syndrome is inherited as an X-linked recessive trait.  Human traits,
including the classic hereditary diseases, are the product of the interaction
of two genes, one received from the father and one from the mother.  X-linked
recessive disorders are conditions which are coded on the X chromosome.
Females have two X chromosomes, but males have one X chromosome and one Y
chromosome.  Therefore, in females, disease traits on the X chromosome can be
masked by the normal gene on the other X chromosome.  Since males only have
one X chromosome, if they inherit a gene for a disease present on the X, it
will be expressed.  Men with X-linked disorders transmit the gene to all
their daughters, who are carriers, but never to their sons.  Women who are
carriers of an X-linked disorder have a fifty percent risk of transmitting
the carrier condition to their daughters, and a fifty percent risk of
transmitting the disease to their sons.

Affected Population

FG Syndrome is an uncommon disorder present at birth which affects males.
Some females may have certain physical characteristics related to FG Syndrome
because they are "carriers" of the trait but they are not affected by the
disorder itself.

Related Disorders

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

Townes-Brocks Syndrome is a rare genetic disorder present at birth.
Characteristics of the disorder and the severity of these symptoms vary from
person to person.  Major characteristics may include an absence of an anal
opening in association with hand, foot and ear abnormalities.  Hearing loss
or deafness due to lesions or dysfunctions of part of the internal ear or its
nerve tracts and centers (sensorineural hearing loss or deafness) is present
in some patients.  (For more information on this disorder, choose "Townes-
Brocks" as your search term in the Rare Disease Database).

VACTERL Association is an acronym for (V)ertebral anomalies, (A)nal
atresia (absence of a normal anal opening), congenital (C)ardiac disease,
(T)racheo(E)sophageal fistula (abnormal openings or passages between the
windpipe and/or upper digestive tract), (R)enal anomalies, radial defects,
and other (L)imb defects.  These abnormalities are present at birth.
Symptoms occur in various combinations and can be manifestations of several
recognized disorders.  (For more information on this disorder, choose
"VACTERL" as your search term in the Rare Disease Database).

REAR Syndrome is an acronym for (R)enal anomalies, deformed external
(E)ars and perceptive deafness, (A)nal stenosis, and (R)adial dysplasia.
Underdeveloped kidneys are the most common renal abnormalities.  The external
ears are abnormally developed and deafness is present at birth.  The anus is
constricted or smaller than normal and other anal abnormalities can also
occur.  Abnormal development of the bone in the forearm (radius) or upper arm
also occurs.

Therapies:  Standard

Surgery to correct malformations may help individuals with FG Syndrome.
Genetic counseling may be of benefit for patients and their families.  Other
treatment is symptomatic and supportive.  Special education services should
be helpful for children with this disorder.

Therapies:  Investigational

Scientists are trying to locate the gene on the X chromosome that causes FG
Syndrome.  When the gene is identified, a prenatal diagnostic and carrier
test may be developed for FG Syndrome.

This disease entry is based upon medical information available through
January 1991.  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 FG Syndrome, please contact:

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

     FG Syndrome Support Group
     66 Ford Road
     Dagenham, Essex, RM10 9JR
     England

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

     Dr. John Opitz
     Shodair Children's Hospital
     P.O. Box 5539
     Helena, MT 59604

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; Johns Hopkins
University Press, 1990.  Pp. 1592.

SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th Ed.:  Kenneth
Lyons Jones, M.D.; W.B. Saunders Co., 1988.  Pp. 240-241.

FG SYNDROME UPDATE 1988:  NOTE OF 5 NEW PATIENTS AND BIBLIOGRAPHY.  J. M.
Opitz, et al.; Am J Med Genet (May-Jun 1988; issue 30 (1-2)).  Pp. 309-328.

SENSORINEURAL DEAFNESS IN THE FG SYNDROME:  REPORT ON FOUR NEW CASES.  G.
Neri, et al.; Am J Med Genet (Oct 1984; issue 19 (2)).  Pp. 369-377.

THE FG SYNDROME:  FURTHER CHARACTERIZATION, REPORT OF A THIRD FAMILY, AND
OF A SPORADIC CASE.  V. M. Riccardi, et al.; Am J Med Genet (1977; issue 1
(1)).  Pp. 47-58.

THE FG SYNDROME:  7 NEW CASES.  E. M. Thompson, et al.; Clin Genet (Jun
1985; issue 27 (6)).  Pp. 582-594.