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$Unique_ID{BRK04279}
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$Title{Townes-Brocks Syndrome}
$Subject{Townes-Brocks Syndrome Townes Syndrome Anus Imperforate with Hand
Foot and Ear Anomalies Deafness Sensorineural with Imperforate Anus and
Hypoplastic Thumbs Imperforate Anus VACTERL Association REAR Syndrome
Holt-Oram Syndrome }
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Copyright (C) 1990 National Organization for Rare Disorders, Inc.

823:
Townes-Brocks Syndrome

** IMPORTANT **
It is possible that the main title of the article (Townes-Brocks
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

     Townes Syndrome
     Anus, Imperforate, with Hand, Foot and Ear Anomalies
     Deafness, Sensorineural, with Imperforate Anus and Hypoplastic Thumbs

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

     Imperforate Anus
     VACTERL Association
     REAR Syndrome
     Holt-Oram 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.

Townes-Brocks Syndrome is a rare genetic disorder present at birth.
Symptoms 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.

Symptoms

Townes-Brocks Syndrome is a rare genetic disorder.  Characteristics of this
disorder are present at birth and vary from person to person both in type and
severity.

ABNORMALITIES OF THE FACE AND EARS
One side of the face may be smaller than normal (hemifacial microsomia)
in individuals with Townes-Brocks Syndrome.  External ears can be abnormally
large, poorly-formed, or abnormally small (microtia, hypoplastic ears).
There may be excess tags of flesh in front of the ears (preauricular
protuberances or tags).  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.

ABNORMALITIES OF THE HANDS AND FEET
Thumbs of Townes-Brocks Syndrome patients may be smaller than normal
(hypoplastic) or may appear to look more like a finger than a thumb.  There
may be an extra joint or bone in the thumb (triphalangeal thumb) and/or an
extra thumb or finger (hexadactyly).  Other hand and foot malformations may
occur as well.  There may be webbing between two or more fingers or toes
(syndactyly).  Fusions of bone may be present in the wrist.  In the feet,
fusion of the long bones (metatarsals) may occur, and/or these bones may be
shorter than average.  Some bones may be absent.  The third toe may be
missing or underdeveloped (hypoplastic).  The fifth toe, or one or more of
the fingers of the hand, may be malformed (clinodactyly).

ANAL ABNORMALITIES
In most patients with Townes-Brocks Syndrome, there is an absence of an
anal opening (imperforate anus).  Abnormal passages from hollow organs to the
body surface or to another organ (fistulas), such as between the rectum and
genitals (rectovaginal fistula or rectoperineal fistula), may be present.  In
some patients, abnormal placement of the anus can occur, and/or the anus may
be constricted or smaller than normal (stenosis).  Other abnormalities such
as abnormal ridges of the genitals (perineal raphe) can also occur.

RENAL ABNORMALITIES
Underdeveloped kidneys (renal hypoplasia) or other related abnormalities
(urorenal anomalies) can occur.  Sometimes urine which is supposed to flow
from the kidneys to the bladder flows backward (ureterovesical reflux).

OCCASIONAL ABNORMALITIES
Other characteristics of Townes-Brocks Syndrome can include indentations
in front of the ears (preauricular pit), and/or heart (cardiac) defects.
Part of the small intestine may be narrowed or occluded (duodenal atresia).
Females may develop cysts in the ovary (cystic ovary).  In the male there may
be an opening located on the underside of the penis (hypospadias); in the
female the urethra may open into the vagina.

Causes

Townes-Brocks Syndrome is inherited as an autosomal dominant 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 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

Townes-Brocks Syndrome is an extremely rare disorder present at birth.  It
affects males and females in equal numbers.

Related Disorders

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

Imperforate Anus is a rare abnormality characterized by the absence or
abnormal localization of the anus present at birth.  The rectum or the colon
may be connected to the vagina or the bladder by a tunnel (fistula).  With
surgical correction, normal elimination can become possible.  Imperforate
Anus can occur alone or as a symptom of another disorder.  (For more
information on this disorder, choose "imperforate anus" 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 upper digestive tract), (R)enal anomalies, radial dysplasia, and
other (L)imb defects.  Abnormalities are present at birth.  Symptoms occur in
various combinations and can be manifestations of several recognized
disorders.

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 tissue development is present in the area of the bone in the
forearm (radius).  (For more information on these disorders, choose "VACTERL"
as your search term in the Rare Disease Database).

Holt-Oram Syndrome, also known as Atriodigital Dysplasia or Heart-Hand
Syndrome, is a genetic disorder comprised of atrial septal defect in
association with hand and forearm deformities.  (For more information on this
disorder, choose "Holt" as your search term in the Rare Disease Database).

Therapies:  Standard

Treatment of Townes-Brocks Syndrome often includes surgery for malformations
associated with this syndrome.  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
November 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 Townes-Brocks Syndrome, please contact:

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

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

     Hemifacial Microsomia Family Support Network
     84 Glennifer Hill Rd.
     Richboro, PA  18954
     [phone]

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, 8th Ed.:  Victor A. McKusick; Johns Hopkins
University Press, 1986.  Pp. 69.

SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th Ed.:  Kenneth
Lyons Jones, M.D.; W.B. Saunders Co., 1988.  Pp. 218-219.

A NEW FAMILY WITH THE TOWNES-BROCKS SYNDROME.  M. A. de Vries-Van der
Weerd, et al.; Clin Genet (Sep 1988; issue 34 (3)).  Pp. 195-200.

PHENOTYPIC VARIABILITY IN TOWNES-BROCKS SYNDROME.  J. Monteiro de Pina-
Neto; Am J Med Genet (May 1984; issue 18 (1)).  Pp. 147-152.

TOWNES-BROCKS SYNDROME.  REPORT OF A CASE AND REVIEW OF THE LITERATURE.
F. G. Ferraz, et al.; Ann Genet (1989; issue 32 (2)).  Pp. 120-123.

TOWNES SYNDROME.  A DISTINCT MULTIPLE MALFORMATION SYNDROME RESEMBLING
VACTERL ASSOCIATION.  J. H. Hersh, et al.; Clin Pediatr (Phila) (Feb 1986;
issue 25 (2)).  Pp. 100-102.