FRIEDREICH'S ATAXIA
What is Friedreich's Ataxia?
Friedreich's ataxia was the first form of hereditary ataxia to be
distinguished from other forms of ataxia. It is named after the
German doctor, Nikolaus Friedreich, who first described it in
1863.
What are the major symptoms of Friedreich's ataxia?
The symptoms of Friedreich's ataxia usually become noticeable
during the early teenage years, although in occasional
individuals the diagnosis has been made as early as age 2 or as
late as age 25. The first symptoms are usually difficulty with
balance (dysequilibrium), impaired coordination of the legs or
arms (ataxia), and thick or slurred speech (dysarthria).
As time goes on, individuals with Friedreich's ataxia often
notice worsening of their coordination and speech, difficulty
knowing where their feet or hands are in space (impaired position
sense), and weakness and loss of muscle bulk in the legs and
hands. Curvature of the spine (kyphoscoliosis) and high arches
in the feet (pes cavus) develop, and may require treatment.
Enlargement of the heart, irregular heartbeat, or other symptoms
of heart trouble (cardiomyopathy) occur in most individuals with
Friedreich's ataxia; the heart trouble may be very mild, but in
most cases it can be severe.
What other symptoms might occur?
About 10% of people with Friedreich's ataxia have hearing loss.
A similar percent develop loss of visual acuity or changes in
color vision. Most have jerky eye movements (nystagmus), but
these movements by themselves do not usually interfere with
vision. About 50% of people develop trouble controlling their
urge to urinate (urinary urgency), or incontinence. A
significant percentage of people with Friedreich's develop
diabetes mellitus, and some patients develop hypothyroidism.
How is Friedreich's ataxia passed on in the family?
Friedreich's ataxia is an inherited, or genetic, disorder. That
means that it is caused by an abnormality of a single gene. To
understand how the disease is passed on, it is important to know
about genes and cells. Each gene is like a blueprint that tells
the cell how to make a certain chemical or protein (like heart
muscle proteins, or neurotransmitter, or eye color pigments). It
is estimated that humans have about 100,000 genes inside each of
their body cells; not all genes are active in all the cells (for
instance, a gene for heart muscle protein doesn't need to be
active in a brain cell). Each egg cell that a woman makes
contains one copy of each of the 100,000 genes, and one copy of
each of the father's genes is contained in his sperm cell, so
that when a new person arises from the joining of an egg and a
sperm cell, the new person has two copies of each gene (one from
his father, and one from his mother).
All people have genes that do not work properly (think of them as
blueprints with a window or a door missing). In the case of
Friedreich's ataxia, and a number of other hereditary diseases,
symptoms do not appear unless a person has a double dose of an
altered, or nonfunctioning, Friedreich's gene. People who have
one copy of an altered "Friedreich's gene" are called "carriers"
of Friedreich's ataxia and can pass their altered gene on to
their children, but these carriers do not have any symptoms of
Friedreich's ataxia. That is because the second copy of the
Friedreich's gene is still working, and that is enough to prevent
any symptoms from occurring. It is only people who get a "double
dose" of the altered gene, so that neither copy of their
"Friedreich's genes" works properly, who develop symptoms that
are recognized as Friedreich's ataxia.
This genetic pattern is called "autosomal recessive inheritance",
which means that 1) the disease is hereditary, 2) a double dose
of the altered or nonfunctioning gene is required to cause
symptoms, 3) the disease can strike males and females with equal
likelihood, and 4) that it is possible to "carry" the altered
gene without having symptoms of the disease.
In the United States, it has been estimated that 1 out of every
100 people is a carrier of the (altered) Friedreich's gene. In
some regions or ethnic groups, this number may be a little higher
or lower, but if you look around you at a busy airport or
football game, there are probably several people there who are
carriers AND DON'T KNOW IT. Most of the time, the development of
Friedreich's in a child comes as a complete surprise to their
parents, who had no way of knowing that they were carriers of the
Friedreich's gene.
What should somebody with Friedreich's ataxia do?
A number of things are very important for a person with
Friedreich's and his or her family to do. Most importantly, they
should have a thorough evaluation by a physician or neurologist
who is sensitive to all the possible complications of
Friedreich's. An individual with Friedreich's may need a
neurologic examination and tests (which may include evaluation of
the cerebellum and spine cord with CT (computerized tomography)
or MRI (magnetic resonance imaging), studies of the peripheral
nerves with EMG (electromyography), and other studies to rule out
other conditions; an ophthalmologic (eye) exam, an audiologic
(hearing) test, evaluation and treatment by an orthopedist (bone
doctor), an EKG (electrocardiogram), and perhaps evaluation by an
endocrinologist (diabetes, thyroid doctor). Evaluation or
treatment by a speech pathologist, physical or occupational
therapist, and urologist may become necessary as the disease
progresses.
Patients and families with Friedreich's ataxia should undergo
genetic counseling. Family members usually have many questions
about the chances that other children might get or have the
disease, or be carriers of the disease gene. These questions, as
well as questions about the rapidly evolving technology for
genetic testing for Friedreich's can be answered by a genetic
counselor.
A family with Friedreich's should become knowledgeable about
Friedreich's. Many physicians are unaware of all the medical and
social aspects of Friedreich's, and the family can help health
professionals, friends, and relatives by learning about the
disease. The National Ataxia Foundation, who has a series of
informational brochures, quarterly newsletter, and an updated
annual list of published research articles. Learn from other
individuals and families who have ataxia through an established
computer bulletin board, join one of NAF's chapters or support
groups and or the "Pen-Pals". You and your doctor might want to
read recently (1992-1993) published books (written for the
physician) on ataxia:
1. Serotonin, The Cerebellum and Ataxia, Dr. Paul
Trouillas and Dr. K. Fuxe. (Raven Press, New
York, 1993)
2. Handbook of Clinical Neurology, Vol. 60,
"Hereditary neuropathies and spinocerebellaratrophies," Eds. Vinken, Bruyn, and Klawanserdam, New York, 1992)
3. The Handbook of Cerebellar Diseases, Ed.center>
Richard Lechtenberg (Marcel Dekker, Inc.,
New York, 1993) It covers anatomy, history,
examination, causes of cerebellar diseases,
genetic research, and treatment. Highly
recommended)
4. Inherited Ataxias. Vol. 61, Advances in
Neurology, Eds. Anita Harding and T. Deufel
(Raven Press, New York 1993)
Do not lose hope! Whatever the disabilities you now have or may
develop in the future, only you can determine whether or not you
will let them handicap you. True, you may be limited in a number
of ways, but there are many things you can do despite these
limitations. Work with your uniqueness, your abilities and
talents, use them to the fullest. Be determined and reach for
your highest goals in life: spiritually, emotionally, and
physically. Appreciate what you do have. Enjoy people and
things to the fullest. Live one day at a time. It's all any of
us really have. Do what you can to make the most of your
situation, and then relax, and let be.
NATIONAL ATAXIA FOUNDATION
2600 Fernbrook Lane, Suite 119
Minneapolis, MN 55447-4752
Phone: (763) 553-0020
FAX: (763) 553-0167
Email: naf@ataxia.org
Copyright 1993 by the National Ataxia Foundation, Inc.
All rights reserved