| THE DISEASE
Spinal muscular atrophy (SMA), the number one genetic killer
of children under the age of two, is a group of inherited and
often fatal diseases that destroys the nerves controlling
voluntary muscle movement, which affects crawling, walking, head
and neck control, and even swallowing.
WHO IS AFFECTED?
SMA is one of the most prevalent genetic disorders.
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One in every 6,000 babies is born with SMA. Of
children diagnosed before age two, 50 percent will die
before their second birthday. |
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SMA can strike anyone of any age, race or gender. |
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One in every 40 people carries the gene that causes
SMA. The child of two carriers has a one in four chance
of developing SMA. |
THE TYPES OF SMA
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Type 1, or Werdnig-Hoffman Disease, is the most
severe form of SMA. Children with Type I tend to be weak
and lack motor development, rendering movement
difficult. Children afflicted with Type I cannot sit
unaided and have trouble breathing, sucking and
swallowing. Type I SMA strikes infants between birth and
six months. |
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Type II is slightly less severe. Type II
patients may be able to sit unaided or even stand with
support and usually do not suffer from feeding and
swallowing difficulties. However, they are at increased
risk for complications from respiratory infections. Type
II SMA affects infants between seven and 18 months old. |
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Type III, also known as Kugelberg-Welander
Disease, is the least deadly form of childhood-onset SMA.
Type III patients are able to stand, but weakness is
prevalent and tends to eventually sentence its victims
to a wheelchair. Type III SMA strikes children after the
age of 18 months, but can surface even in adulthood. |
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Type IV is the adult form of the disease in
which symptoms tend to begin after age 35. Symptoms
usually begin in the hands, feet and tongue, and spread
to other areas of the body. |
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Adult Onset X-Linked SMA, also known as
Kennedy's Syndrome or Bulbo-Spinal Muscular Atrophy,
occurs only in men. Facial and tongue muscles are
noticeably affected. In addition, these men also often
have breast enlargement known as gynecomastia.
Like all forms of SMA, the course of the disease is
variable, but in general tends to progress slowly. |
SMA does not affect sensation and intellectual activity in
patients. It commonly is observed that patients with SMA are
unusually bright and sociable.
RESEARCH NEWS AND UPDATES
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May 24, 2001 --
Scientists have found evidence suggesting that the
severity of spinal muscular atrophy (SMA) may be
ameliorated by common vitamins.
The findings by researchers at the
University of Pennsylvania School of Medicine, which are
to be published Thursday in the journal Molecular Cell
suggest that folic acid and Vitamins B12 may limit the
severity of symptoms that afflict SMA patients.
"We are not suggesting that this
is a cure. But it may help," said Gideon Dreyfuss,
PhD, Isaac Norris Professor of Biochemistry and a Howard
Hughes Medical Institute Investigator at Penn, and
principal author of the study.
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August 24, 2000, - A significant
breakthrough in identifying a treatment for Spinal
Muscular Atrophy is being announced by an International
team of researchers. The research, funded in part by
Families of SMA, helps to identify what types of
therapeutic approaches may be successful.
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March 22, 2000 -- The
group of J. Melki (French National Institute of Health and
Medical Research, INSERM), publish the creation and
characterization of a mouse model of SMA, a frequent
neuromuscular disease characterized by degeneration of
neurons of the spinal cord.
Dr. Melki's mouse model closely
resembles a type II/III phenotype. This mouse model will
allow researchers to continue to study SMA at a molecular
level. It will also be used to identify and test
therapeutic strategies and the effectiveness of compounds
discovered in the high-throughput drug screening.
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In 1999, investigators at
The Ohio State University replicated SMA in a mouse model.
The researchers have demonstrated that when the mice have
high amounts of the SMN2 gene, which is present in all human
SMA patients, the SMA phenotype is corrected and they
develop normally. These findings support the conclusion that
large amounts of the protein could act to prevent the damage
caused by SMA or even reverse the impact of the disease.
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