Unraveling the Mystery of Amyotrophic Lateral Sclerosis

Siena Kontopirakis
Aug 14
3 min read

In recent celebrity news, you might have heard that former acting star of Grey's Anatomy, Eric Dane, has been diagnosed with Amyotrophic Lateral Sclerosis, commonly known as ALS. ALS is a neurodegenerative disease which in non-medical terms basically means the disease progresses over time, getting worse and worse. This condition affects how the nerve cells in the brain and spinal cord communicate with muscle cells, ultimately causing the loss of muscle control. Strangely enough, this neurological disease has both no cure and cause. Scary right?! Hopefully, in the bright future of medical research, there will be a cure and definitive cause for ALS. Although the cause is said to be ‘unknown’, scientists state that the cause is both genetic and environmental factors, with 90% sporadic or random and the remaining 10% familial or passed down through generations.

Symptoms of ALS

How I like to remember the symptoms of ALS is with the help of the mnemonic FALS. F stands for Fasciculations in medical terms, simply meaning involuntary muscle twitches often in the hand and feet, presentable in the earlier stages of ALS. The ‘A’ stands for atrophy, meaning muscle wasting or shrinking, typically in the hands and limbs, due to loss of nerve supply. The ‘L’ is for loss of motor control such as difficulty with fine motor skills and progressive weakness in limbs. Lastly, the ‘S’ is for speech and swallowing difficulties. Other symptoms may range from muscle cramps, fatigue or even inappropriate crying or laughing. But why does this disease cause all these types of symptoms?

Why do these symptoms arise

For starters, ALS causes the degradation and death of motor neurons ultimately leading to loss or weakening of muscles due to the lack of connection or signalling between the motor neurons and muscles. More specifically, there are multiple factors that lead to the degradation of motor neurons, including protein misfolding, excitotoxicity and the dysfunctioning of support cells. Looking deeper into why the motor nerve cells degrade from protein misfolding, it is because proteins like TDP-43 misfold and aggregate which disrupts normal functioning of motor nerves. Furthermore, these aggregates can interfere with cellular processes including protein synthesis, waste removal and transport, as well as disrupting gene regulation.

Secondly, excitotoxicity occurs when excessive levels of the neurotransmitter glutamate can accumulate around motor neurons, leading to overstimulation, damage and the degradation of motor neurons. Lastly, the dysfunctioning of support cells, typically the mitochondria, can disrupt the energy supply needed for neuronal activity and survival, eventually causing cell damage. To conclude, all of these factors have a major contribution in the degradation of nerve muscles ultimately leading to multiple symptoms such as muscle weakness and complete loss of motor control.

The infographic below can help you better understand what the normal motor neuron looks like compared with a motor neuron with ALS.

Risk factors of ALS

Although the cause of ALS is stated to be unknown, there are risk factors that can increase your likelihood of developing this disease. The risk factors that are uncontrollable are age, sex and genetics. ALS is most common in people of the ages between 60 and 80. However with sex, slightly more men develop ALS, but the sex factor falls away after the ages of 70 and above. Other risk factors that may contribute are environmental, such as smoking, toxin exposure and oddly enough, military service which may be the exposure to certain metals and chemicals.

Conclusion

Overall, ALS is not only just a progressive neurological disease, but rather a significant topic in the world of neuroscience and medicine. A topic that should bring curiosity and excitement into the future of medical and neuroscience research, where bright minds come together to work towards finding a cure and definitive cause for this disease.