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Neurofibromatosis (NF) is a multisystem genetic disorder
that causes tumors—most of them non-cancerous—to
develop in a person’s body. First identified by
the 19th century German pathologist Friedrich Daniel von
Recklinghausen, NF is a manageable, but not curable disorder.
With attentive and appropriate medical care, many NF patients
are able to hold jobs and raise families.
There are two distinct forms of the disorder. Neurofibromatosis,
type 1 (NF1) is characterized by tumors that grow on
or below the skin and in the peripheral nerves. Most
NF1 tumors are benign, but a less common type of NF1
tumors, called plexiform tumors, can become malignant.
In neurofibromatosis, type 2 (NF2), benign tumors grow
on the cranial and spinal nerves. NF1—the most common
type—is found in about 1 in 3,000 people, while NF2
affects about 1 in 40,000 people.
The Genetic Connection
Geneticists have been able to identify the defective
genes for NF1 and NF2. For NF1, the altered gene is
on chromosome 17, and people with this type of neurofibromatosis
cannot produce sufficient amounts of a tumor-suppressing
protein known as neurofibromin. People with NF2 cannot
make enough of merlin, a protein that also suppresses
tumors. The altered gene for NF2 is located on chromosome
22.
Both types of NF are autosomal dominant genetic disorders,
which means they can be passed on to one’s children.
A person with NF has a 50 percent chance of contributing
the NF gene to a son or a daughter. The type of NF is
always the same from one generation to the next; a person
with NF1 can’t pass on the gene for NF2. In some
families, there are a number of people with NF. However,
NF can also occur spontaneously in an individual where
there is no known family history; this is known as a
new mutation.
There are prenatal genetic tests for neurofibromatosis.
While test results can provide very important information
for future parents, like any tests, there are some caveats.
The genetic tests available today can be performed only
when there is a family history of NF; even then, testing
may or may not be possible depending upon the family
structure and results of preliminary DNA tests. Any
time NF is diagnosed, an entire family is potentially
impacted. It is important to speak with a genetic counselor
about NF and how it can be passed on within a family.
The Outlook for NF
NF is a disorder that always needs to be carefully
monitored. The patients who fare the best are the ones
who are proactive about their health, keeping regular
doctors’ appointments and not hesitating to seek
medical care when even seemingly minor physical changes
occur. NF is also a condition that, due to its complexity,
is best addressed by a multidisciplinary health care
team.
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