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$Unique_ID{BRK03401}
$Pretitle{}
$Title{13q- Syndrome}
$Subject{13q- Syndrome 13q- Chromosomal Syndrome 13q- Mosaicism Monosomy 13
Trisomy 13 Translocation 13 Inversion (Insertion) 13 Ring 13 4p- Syndrome
(Wolf-Hirschhorn Syndrome) 5p- Syndrome (Cri du Chat Syndrome) 18p- Syndrome
18q- Syndrome}
$Volume{}
$Log{}

Copyright (C) 1989 National Organization for Rare Disorders, Inc.

643:
13q- Syndrome

** IMPORTANT **
It is possible that the main title of the article (13q- 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

     13q- Chromosomal Syndrome

Disorder Subdivisions:

     13q- Mosaicism
     Monosomy 13
     Trisomy 13
     Translocation 13
     Inversion (Insertion) 13
     Ring 13

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

     4p- Syndrome (Wolf-Hirschhorn Syndrome)
     5p- Syndrome (Cri du Chat Syndrome)
     18p- Syndrome
     18q- 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.

13q- Syndrome is a chromosomal disorder caused by a partial deletion of
chromosome 13.  Major symptoms may include an unusually small head
(microcephaly), growth and mental deficiencies, and retinoblastoma (malignant
tumor of the retina).

Symptoms

13q- patients may have mental and psychomotor (motor activity resulting from
mental activity) retardation and growth deficiency.  They have an unusually
small head which may be triangular and flat (trigonocephaly) and may have an
underdeveloped forebrain (holoprosencephaly).  A prominent nasal bridge,
droopy wide-set eyes (ptosis, hypertelorism), excess skin over the inner
corner of the eyes (epicanthic folds), and unusually small eyes
(microphthalmia) may also occur.  Eye defects (colobomata), malignant tumors
of the retina (retinoblastoma), a large upper jaw (maxilla), and a small
lower jaw (micrognathia) may also be present.  Large slanted low set ears, a
short webbed neck, small or absent thumbs, abnormally placed fifth fingers
(clinodactyly), and short big toes also occur.  13q- patients may have
permanently flexed soles so that walking is done on the toes.

Failure of the testes to descend into the scrotum (cryptorchidism) and a
two-lobed scrotum may occur in males.  The urethra (the tube leading from the
bladder) may open underneath the penis in males (hypospadias) or it may open
into the vagina in females.  There may be heart (cardiac), pelvic, and
kidney (renal) defects.  The vertebrae between the ribs and the pelvis
(lumbar) may be underdeveloped.  Abnormal development (dysplasia) of the
nerve of the eye and the retina, a narrow palate, eczema, and an asymmetrical
face may occur.  The normal opening of the rectum may be absent (imperforate
anus).  The normal suck and swallowing reflex may be absent in infants.

Disorder Subdivisions
Syndromes which involve other deviations of chromosome 13 may be similar
to 13q- Syndrome.

13q- Mosaicism is a disorder in which some cells of the body have a
partial deletion in the long arm of chromosome 13 and other cells are normal.
The symptoms of 13q- Mosaics are those described for 13q- Syndrome (see
Symptoms section) but with a greater variability in type and severity due to
the presence of normal cells.

Monosomy 13 may refer to any deletion of chromosome 13.  Part or all of
the short arm ('p') and/or the long arm ('q') of the chromosome may be
missing.  Since chromosomes occur in pairs, Monosomy 13 may also refer to the
absence of one of the pair.  Symptoms may be similar to those of 13q-
Syndrome.

Trisomy 13 Syndrome (Patau's Syndrome) is characterized by an additional
chromosome 13 (three copies instead of two).  Brain defects, mental
retardation, abnormal ears, hearing difficulties, eye defects, cleft lip, and
cleft palate may also occur.  An unusual creases across the palms (simian
crease), extra fingers and toes (polydactyly), heart defects including right
side location of the heart (dextrocardia), and abnormal genitalia are common.
(For more information on this disorder, choose "Trisomy 13" as your search
term in the Rare Disease Database.)

Translocation 13 is identified by the exchange of parts between
chromosome 13 and another chromosome.  Malignant tumors of the eye
(retinoblastoma), decreased muscle tone (hypotonia), and developmental delay
may occur.  Some symptoms that occur with 13q- Syndrome may also be
associated with this chromosomal deviation.

Intrachromosomal Insertion of Chromosome 13 involves the breaking off of
a section of chromosome 13 and its subsequent reattachment in a different
way, such as upside-down (inversion).  Mental deficiency, personality
defects, psychosis, and other symptoms may occur.

13 Ring Chromosome is characterized by chromosome 13 being a ring.  When
parts of the ring chromosome are missing, many of the abnormalities shown are
those described for 13q- Syndrome patients in the Symptomatology section.

Causes

A partial deletion of the long arm ('q') of chromosome 13 causes the
abnormalities of 13q- Syndrome.  The severity and type of abnormalities
depend on the size and location of the missing chromosomal piece.

Affected Population

13q- Syndrome is a rare genetic disorder that is present at birth.  It
affects males and females in equal numbers.

Related Disorders

Symptoms of the following disorders can be similar to those of 13q- Syndrome.
Comparisons may be useful for a differential diagnosis:

4p- Syndrome (Wolf-Hirschhorn Syndrome) is characterized by a partial
deletion of the short arm of chromosome 4.  Mental and growth deficiencies,
unusually small head, droopy wide-set eyes, excess skin over the inner corner
of the eyes (epicanthic folds), and eye defects may occur.  Small jaws
(micrognathia), cleft lip, cleft palate, downturned 'fish-like' mouth, low-
set ears, and a beaked broad nose may also occur.  There may be unusual
creases across the palms (simian crease).  4p- patients may have permanently
flexed soles so that walking is done on the toes.  Failure of the testes to
descend into the scrotum (cryptorchidism) may occur in males.  The urethra
(the tube leading from the bladder) may open underneath the penis
(hypospadias) or it may open into the vagina.  Heart (cardiac) and kidney
(renal) defects may be present.  Decreased muscle tone (hypotonia) and
seizures may also occur.  (For more information on this disorder, choose
"Wolf-Hirschhorn" as your search term in the Rare Disease Database.)

5p- Syndrome (Cri du Chat Syndrome) is identified by a partial deletion
of the short arm of chromosome 5.  Mental and growth deficiencies, unusually
small head, wide-set eyes, epicanthic folds, and nearsightedness (myopia) may
occur.  Cleft lip, cleft palate, low-set poorly formed ears, and a short neck
may also occur.  There may be simian creases on the palms and abnormally
placed fingers (clinodactyly).  Cri du Chat babies may have undescended
testes, absent kidney and spleen, curvature of the spine (scoliosis),
premature graying, and breathing and feeding problems.  Hypotonia (decreased
muscle tone) and a high, shrill cry may also occur.  (For more information on
this disorder, choose "Cri du Chat" as your search term in the Rare Disease
Database).

18p- Syndrome involves a partial deletion of the short arm of chromosome
18.  Mental and growth deficiencies, unusually small head rarely with an
underdeveloped forebrain (holoprosencephaly), droopy wide-set eyes with
cataracts, small jaws, wide downturned mouth, large protruding ears, and
webbed neck may also occur.  There may be simian creases on the palms,
abnormally placed fifth finger (clinodactyly), and small hands and feet.  18
patients may have permanently flexed soles so that walking is done on the
toes.  Decreased muscle tone (hypotonia), absent or deficient IgA (particular
antibodies that fight foreign organisms in the body that is present in
saliva, tears, and sweat), and rheumatoid arthritis-like symptoms may occur
in the joints.

18q- Syndrome is characterized by a partial deletion of the long arm of
chromosome 18.  Mental and growth deficiency with hypotonia and unusually
small head may occur.  The eyes may move back and forth rapidly (nystagmus),
be wide-set and droopy, and have epicanthic folds.  Cleft palate, low-set
ears, deafness, simian creases on the palms, and abnormally placed toes may
also occur.  18q- patients may have permanently flexed soles so that walking
is done on the toes.  Males may have undescended testes.  Females may have an
underdeveloped labia minora (a part of the external genitalia, the vulva).
Eczema, absent or deficient IgA, an extra rib, kidney defects, and widely
spaced nipples may also occur.

Therapies:  Standard

Special education and physical therapy services may be of benefit for the
13 patient.  Genetic counseling may be of benefit for affected families.
Other treatment is symptomatic and supportive.

Therapies:  Investigational

This disease entry is based upon medical information available through April
1989.  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 13q- Syndrome, please contact:

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

     Support Group for Trisomy 18/13 (S.O.F.T.) and Other Related Disorders
     9349 S. 12th Street
     Schoolcraft, MI  49087

     Chromosome Deletion Outreach
     P.O. Box 164
     Holtsville, NY  11742
     [phone]

     NIH/National Institute for Child Health & Human Development (NICHHD)
     9000 Rockville Pike
     Bethesda, MD  20892
     [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, 7th ed.:  Victor A. McKusick; Johns Hopkins
University Press, 1986.  Pp. 655-659.

SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th ed.:  Kenneth L.
Jones; W.B. Saunders Company, 1988.  Pp. 38-41, 54-59.

INTERSTITIAL DEL (13)(q21.3q31) ASSOCIATED WITH PSYCHOMOTOR RETARDATION,
ECZEMA, AND ABSENT SUCK AND SWALLOWING REFLEX:  P.J. Peet et al.; J Med Genet
(December, 1987:  issue 24(12)).  Pp. 786-788.

INTRACHROMOSOMAL INSERTION OF CHROMOSOME 13 IN A FAMILY WITH PSYCHOSIS
AND MENTAL SUBNORMALITY:  S.H. Roberts et al.; J Ment Defic Res (September,
1986:  issue 30(part 3)).  Pp. 227-232.