Alternative Names
ALS; Lou Gehrig's disease; Charcot disease
Symptoms & Characteristics
Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease,
is a nervous system disease that attacks motor neurons in the brain and the
spinal cord. Motor neurons are responsible for coordinating signals between the
brain and spinal cord and muscles to control movement. In the beginning, this
causes mild muscle problems, like walking or writing. Eventually, the problems
worsen and an affected person cannot move or breathe.
Symptoms of the disease usually appear between age 40 and 60. ALS can run in
families with more than one affected family member, called familial ALS (FALS),
but typically strikes at random with no family history, called sporadic ALS
(SALS). FALS and SALS are clinically similar. However, most people with SALS
have symptom onset at about 56 years old, while most people with FALS have
symptom onset at about 46 years old.
Management & Treatment
Early diagnosis, routine surveillance, and treatment of ALS may help to manage some of the symptoms. Individuals with ALS may benefit from care by a multidisciplinary team that includes a neurologist, specially trained nurses, pulmonologist, speech therapist, physical therapist, occupational therapist, respiratory therapist, nutritionist, psychologist, social worker, and genetics professional.
Riluzole is currently the only FDA-approved drug for treatment of ALS.
Medications may be offered for extra saliva or drooling. Antidepressants may be offered to help manage emotional lability. Medications, such as baclofen and benzodiazepines, may help relieve spasticity and muscle cramps.
Swallowing difficulties may be alleviated by thickening liquids and pureeing solid food and, eventually, by use of a gastrostomy tube to help maintain caloric intake and hydration.
Assistive devices, such as walkers, wheelchairs, bathroom modifications, hospital beds, and hoyer lifts can aid in activities of daily life. Breathing devices and computer-assisted speaking devices may also be needed.
How Common Is It?
About 30,000 people are affected with ALS in the United States. More men
than women are typically affected.
Genetics & Inheritance
The cause of SALS is largely unknown.
Sporadic ALS is most likely multifactorial condition, which means that it
involves a combination of genetic, lifestyle and environmental factors.
- Many environmental factors have been proposed to possibly contribute to
ALS, including (but not limited to): mercury, manganese, formaldehyde,
farming chemicals (fertilizers, insecticides, herbicides); as well as
physical and dietary factors.
Familial ALS makes up about 10% of total cases of ALS. Different types of
FALS are distinguished by their genetic cause, the age at which symptoms began
(age of onset), and disease progression (slow or fast). Although 9 types of ALS
have currently been identified, only a small percentage of cases have actual
known genes and established patterns (modes) of inheritance. As of yet,
researchers have only adequately identified and classified genetic mutations
that cause ALS types 1, 2, 4, and 8.
We all have two copies of each of above genes - one from each parent. The
pattern of inheritance of FALS varies by type.
- In types 1, 4 and 8, having a mutation in a single gene copy is
sufficient to cause the disease. However, not every person who has a
mutation will develop physical symptoms in their lifetime. This is called
autosomal dominant inheritance with incomplete
penetrance. Every person with a mutation has a 50% chance to pass on
their mutation to each child they have.
- In type 2, and some cases of type 1, it is necessary to have two
mutations, one in each copy, to be affected. This is called autosomal recessive inheritance. Both parents of
affected people are always obligate carriers (each have only one mutation).
Two carriers have a 25% chance in each pregnancy to have an affected child,
but do not have symptoms themselves.
In addition, some genes do not cause ALS, but instead have been associated with
an increased risk (or susceptibility) to develop ALS.
- Mutations in a number of other genes including, ANG, DCTN1, NEFH, or PRPH
genes appear to increase the risk to develop ALS.
- Some studies suggest that a decrease in the number of SMN1 or SMN2 genes
may also lead to an increased susceptibility to or severity of ALS, but
exactly how is unclear at this time.
Not all genes that cause ALS or cause susceptibility to ALS are known at this
time.
There are other genetic and non-genetic conditions, which have symptoms that
overlap with ALS. As such, a genetic consultation with a trained genetic professional may be beneficial for a complete evaluation and accurate diagnosis.
Genetic Testing
Clinical genetic testing for ALS (types 1, 2, 4, and 8) may
be available through
genetic consultation for people who are considered at risk. A trained
genetic professional can discuss the benefits and limitations of genetic testing for ALS, coordinate testing and interpret results in the context of personal and family medical history.
- A board-certified genetic counselor is available by telephone.
Informational genetic testing for susceptibility to ALS is
available online (over the internet) as part of a whole genome scan. Whole genome scanning involves analyzing thousands of SNPs
at once related to a number of different health conditions.
- At this point, many genetic professionals do not consider this testing
clinically useful or medically relevant, but for informational purposes
only. Go to the Tests tab to link to the best providers, compare
providers and read provider reviews.
Support & More Information
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Last Reviewed January 26, 2010