Neurofibromatosis
What is it?
Neurofibromatosis,
also called von Recklinghausen’s disease, is an
inherited disease that is marked by many soft,
fleshy growths under the skin or elsewhere in the
body. The
growths consist of abnormal nerve tissue, and are
called neurofibromas.
There are two types of neurofibromatosis:
NF-1 accounts for 90% of all cases.
NF-2 is a rare form of the disease where tumors called
acoustic neuromas develop in the inner ear.
NF-2 accounts for only 10% of all cases.
Who gets it?
Neurofibromatosis
occurs in about one of every 4,000 births.
What causes it?
Both forms
of neurofibromatosis are caused by a defective
gene that causes certain cells to develop
abnormally. A
defect on chromosome 17 causes NF-1.
NF-2 results from a defect on chromosome
22. Only
one defective gene is necessary to cause the
disease. It
is interesting to note that only about half of all
cases of neurofibromatosis show a family history
of the disease. The
other cases of neurofibromatosis occur because a
specific gene spontaneously changes its structure
(mutates). A
person with this type of spontaneous mutation can
then pass that gene onto his or her offspring. There
is a 50% chance that a parent with
neurofibromatosis will pass the gene on to a
child.
What are the symptoms?
NF-1 has a
number of possible symptoms.
The most common is six or more medium brown
skin spots (cafe-au-lait spots), generally on the
trunk, elbows, and knees.
These spots may be present at birth or
appear during infancy.
Neurofibromas generally begin to appear
between the ages of 10 and 15.
The growths may cause skeletal deformities,
such as a curvature of the spine or bowed legs.
Other symptoms include multiple freckles in
the armpit or groin area and tiny tumors called
Lisch nodules in the colored part of the eye.
A small number of patients may also have
tumors along the optic nerve that affect vision.
Babies with NF-1 tend to be shorter than average,
with somewhat larger heads.
While NF-1 does not affect intelligence, it often causes
other disorders such as speech impairment,
learning disabilities, attention deficit, and
hyperactivity. Patients
with NF-1 may be more prone to seizures, the
excessive fluid within the brain (hydrocephalus),
and certain cancers.
The main symptom of NF-2 is the
acoustic neuromas that develop in the inner ear.
These tumors can cause hearing loss,
dizziness, facial muscle weakness, headache, and
poor balance. Those
with NF-2 may develop cataracts while very young.
How is it diagnosed?
NF-1 is
diagnosed when at least two of the symptoms listed
above are present. Many
people with neurofibromatosis notice no symptoms.
The disease is diagnosed through routine
examination when the doctor feels lumps under the
skin near nerves. NF-2 is diagnosed when there is
either a growth on the acoustic nerve or another
distinctive nervous system tumor.
Your doctor will also ask whether any close
family members have neurofibromatosis. Diagnostic
imaging tests are a good way to follow the
progression of tumors in the brain and along
nerves.
What is the treatment?
There is no
known treatment to stop the growth of
neurofibromas or cure neurofibromatosis.
Regular exams are necessary to follow the
course of the disease.
Neurofibromas sometimes must be removed
surgically if they damage vital organs, cause
pain, or become infected.
They can also be removed for cosmetic
reasons. Other
complications of the disease are treated
accordingly.
Self-care tips
Neurofibromatosis
that occurs because of a spontaneous gene mutation
cannot be prevented. However,
if you or other family members have been diagnosed
with neurofibromatosis, you may wish to seek the
advice of a genetic counselor before having
children.
Tests can be performed during a pregnancy to determine if the
fetus has inherited the parent's genetic defect.
Many parents use this information to prepare for the arrival
of a child with a serious medical problem.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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