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ALS and Genetic Testing

The majority of ALS diagnoses are sporadic, but genetic testing can help determine if there is a chance of the individual developing familial ALS.
Matt H Sep 24, 2019
Amyotrophic lateral sclerosis (ALS) is a progressive condition that results in the death of neurons in the body which are responsible for controlling voluntary muscle movement.

It's a very serious disease which currently has no cure and individuals diagnosed with ALS typically live for between only 3 and 5 years following their diagnosis.

Symptoms of ALS

The initial symptoms associated with ALS may vary from person to person and the rate in which the disease progresses can also vary significantly.

Muscle weakness is a common initial symptom of the disease and slurred speech may also be an early indicator.

As the disease progresses, ALS can affect the individual's ability to eat and breathe.

Sporadic vs Familial ALS

The most two common classifications of ALS in terms of onset are sporadic ALS (SALS) and familial ALS (FALS).

Sporadic ALS, which is thought to account for around 90% of all cases, refers to instances whereby the individual diagnosed with the disease has no known history of it in their family (i.e. there is no genetic factor thought to be the cause of it).
Familial ALS refers to cases whereby the individual diagnosed with the disease has one or more members within their family who also suffered from it.

In these cases, it is believed that the individual has inherited the disease from one of their parents.

Genetic Testing

Genetic testing can be used to help identify whether or not there is a genetic cause of ALS in the family in an individual who has been diagnosed with the condition.

This type of testing is typically only provided to individuals who are aware of ALS being present in their family history.
Genetic testing typically involves a sample of blood or spit being taken which is then analysed at a specialist laboratory. It can take between a couple of weeks up to several months for the results of the tests to be finalised and revealed to the patient.

The time for results to be completed will vary depending on the type of tests ordered by the doctor.
Genetic testing for ALS is not usually recommended for individuals aged under 18 years old due to the fact that familial ALS is condition which typically develops in adulthood, rather than childhood.

Predictive Testing

Genetic testing can also be offered to the biological family members of an individual diagnosed with familial ALS who has received genetic testing themselves, in the cases where their own test results were positive. This means that family members can see if they have inherited the genetic mutation, even if they are displaying no symptoms of ALS themselves.
Whilst this can be useful to determine if other family members will also be more likely to develop ALS at some point during their lives, genetic testing can not predict when symptoms might begin to show or indeed how quickly the disease will progress.

Better Understanding

An individual may opt for genetic testing to try and understand more clearly why they have ALS. Family members may also opt for tests in order to understand if they too are at risk of this devastating disease. But for some people, having these tests is not something they wish to pursue.

Continued Research

A genetic test for ALS could come back negative, however the individual might still have familial ALS - it may just be that the gene responsible has not yet been discovered and therefore cannot yet be tested for.

But the technology being used for ALS genetic testing continues to improve and more genes are being identified, making them more reliable.

More Information

More information about genetic testing for ALS can be found here, but as this is an area of medicine which is rapidly developing, it is recommended to get in touch with a specialist genetic counsellor to ensure that the most up to date details and options are communicated effectively.