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$Unique_ID{BRK03942}
$Pretitle{}
$Title{Lissencephaly}
$Subject{Lissencephaly Lissencephaly Syndrome Agyria Miller-Dieker Syndrome
Norman-Roberts Syndrome HARD plus/minus-E Syndrome Neu-Laxova Syndrome }
$Volume{}
$Log{}
Copyright (C) 1987, 1990 National Organization for Rare Disorders, Inc.
454:
Lissencephaly
** IMPORTANT **
It is possible the main title of the article (Lissencephaly) is not the
name you expected. Please check the SYNONYMS listing on the next page to
find alternate names, disorder subdivisions, and related disorders covered by
this article.
Synonyms
Lissencephaly Syndrome
Agyria
DISORDER SUBDIVISIONS
Miller-Dieker Syndrome
Norman-Roberts Syndrome
Information on the following diseases can be found in the Related
Disorders section of this report:
HARD plus/minus-E Syndrome
Neu-Laxova 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.
Lissencephaly is a brain formation disorder characterized by the lack of
normal convolutions or folds in the brain. It is thought to be inherited.
Two major subdivisions including Miller-Dieker Syndrome and Norman-Roberts
Syndrome have been identified, although as many as eight variants of
Lissencephaly may exist. An abnormally small head and an unusual facial
appearance, as well as abnormalities of the brain, kidney, heart and
gastrointestinal tract may occur. This disorder may occur alone or as a
symptom of other medical conditions.
Symptoms
Lissencephaly means "smooth brain". It is characterized by an abnormally
small head, an unusual facial appearance, difficulty in swallowing, failure
to thrive, and severe psychomotor retardation. Abnormalities of the hands,
fingers or toes, muscle spasms, and seizures may also occur. Patients with
the Miller-Dieker variant of Lissencephaly tend to have a high, narrow
forehead, prominent back of the head, clouded corneas of the eyes, minor
abnormalities of the ears, underdeveloped jaw, lips with a "carp mouth"
appearance, and the skin of the forehead may be abnormally wrinkled.
A low, sloping forehead and prominent bridge of the nose are often
present in those with the Norman-Roberts variant of Lissencephaly. No
chromosomal abnormality exists in the Norman-Roberts form of Lissencephaly.
Excessive hair growth (hirsutism) may cover many areas of the body.
Symptoms in males may include undescended testicles and hernias. Other
developmental problems such as congenital heart disease, absence of one
kidney, and closure of the normal opening in the part of the intestine called
the duodenum (duodenal atresia) may also occur. Infants with Lissencephaly
may have a bluish coloration of the skin (cyanosis), a feeble cry, and
breathing difficulties while sleeping. Diminished muscle tone (floppiness)
and feeding problems may develop. Initial lack of movement may gradually be
replaced by seizures, rigidity, and spasms marked by an extreme backward bend
of the entire body. Patients may not respond to stimuli, but may be severely
hyperactive at times. Some infants may have enlarged livers and spleens,
prolonged yellow discoloration of the skin (jaundice), and urinary tract
infections.
Causes
Lissencephaly is thought to be inherited as an autosomal recessive trait.
(Human traits including the classic genetic diseases, are the product of the
interaction of two genes for that condition, one received from the father and
one from the mother. In recessive disorders, the condition does not appear
unless a person inherits the same defective gene 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 show no 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.)
Medical researchers have found specific chromosomal abnormalities in some
Lissencephaly patients and speculate that this may be the cause of Miller-
Dieker Syndrome. Symptoms may develop due to interruption of normal fetal
brain development during the fourth month of pregnancy.
Affected Population
Lissencephaly is a very rare disorder beginning before birth which is thought
to affect males and females in equal numbers.
Related Disorders
The following disorders can include Lissencephaly as a symptom. Comparisons
may be useful for a differential diagnosis:
HARD plus/minus-E Syndrome is an acronym for a combination of
Hydrocephalus, Agyria (smooth brain), and Retinal Dysplasia. This disorder
is also known as HARD Syndrome, Warburg Syndrome, Chemke Syndrome, Pagon
Syndrome, Walker-Warburg Syndrome, Cerebroocular Dysgenesis, or COD. The "E"
in the name is included when an abnormal opening of the skull termed
"encephalocele" occurs.
Neu-Laxova Syndrome is marked by intrauterine growth deficiencies and
multiple defects present at birth. Abnormalities of the membrane tissue
connection between the wall of the uterus and the fetus (placenta) occur.
Additionally, the fetus is born with a small head, lack of normal
convolutions and folds of the brain (Lissencephaly or "smooth brain"), and
developmental abnormalities of the limbs, skin, and external genitalia.
Therapies: Standard
Treatment of Lissencephaly is symptomatic and supportive. Genetic counseling
will be of benefit to patients and their families.
Therapies: Investigational
This disease entry is based upon medical information available through March
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 Lissencephaly, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
Lissencephaly Network
7121 Baer Rd.
Ft. Wayne, IN 46809
(219) 747-1075
Dr. William B. Dobyns
Indiana University School of Medicine
Riley Hospital for Children
Neurology Dept., Rm. N102
702 Barnhill Dr.
Indianapolis, IN 46202
(317) 274-8747
Lissencephaly Network
7121 Baer Rd.
Ft. Wayne, IN 46809
(219) 747-1075
NIH/National Institute of Neurological Disorders & Stroke (NINDS)
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-5751
(800) 352-9424
The Children's Brain Diseases Foundation for Research
350 Parnassus, Suite 900
San Francisco, CA 94117
(415) 566-5402
(415) 565-6259
For information on genetics and genetic counseling referrals, please
contact:
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
(301) 652-5553
References
MILLER-DIEKER SYNDROME: LISSENCEPHALY AND MONOSOMY 17P: W.B. Dobyns, et
al.; J Pediatr (April 1983, issue 102(4)). Pp. 552-558.
LISSENCEPHALY AND PACHYGYRIA: AN ARCHITECTONIC AND TOPOGRAPHICAL
ANALYSIS: R.M. Stewart, et al.; Acta Neuropathol (Berl) (1975, issue 31(1)).
Pp. 1-12.
SYNDROMES WITH LISSENCEPHALY. I: MILLER-DIEKER AND NORMAN ROBERTS
SYNDROMES AND ISOLATED LISSENCEPHALY: W.B. Dobyns, et al.; Am J Med Genet
(July 1984, issue 18(3)). Pp. 509-526.