Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig’s Disease, is a neurological disease that affects voluntary muscle movement. ALS takes its name from the famous baseball player Lou Gehrig, whose career was cut short when he began rapidly losing control over his own muscles. Twelve years after his diagnosis of ALS,  Gehrig died from his illness. According to the ALS Association, about two in every 100,000 people suffer from ALS, and much remains to be learned about the disease. To gain an understanding of what doctors know today, here is a guide to the basics of ALS:

ALS is also known as a motor neuron disease (MND) because it afflicts the spinal cord and nerve cells that are responsible for voluntary muscle control. While the brain has specialized neurons in charge of different functions like thought and memory, ALS generally only affects those related to muscle strength and coordination. These muscle groups begin to degenerate and, after a certain point, no longer function. ALS is a progressive disease. Over time, the disease affects more areas of the body. Eventually, afflicted people find it impossible to complete basic tasks like chewing, swallowing or standing.

The first signs of ALS are often so minor that they are ignored. These early symptoms include difficulty with breathing, speaking and swallowing. Other symptoms include muscle weakness as well as twitching and cramping in the hands and feet. Many patients initially feel a sense of clumsiness, tripping over sidewalk curbs or repeatedly dropping objects. The symptoms vary from person to person and affect different body parts, but they generally point to signs of muscle weakness. The long-term symptoms of ALS are often life-threatening. As the disease progresses, afflicted individuals have trouble breathing. Choking is a common complication, and patients who lose control of their swallowing muscles will need to be fed entirely through a feeding tube.

According to the U.S. National Library of Medicine, only 10 percent of ALS cases have been linked to family history. The vast majority of cases are unexplained, and researchers have yet to find a definitive set of causes for the disease. One current hypothesis is gene mutation, which means non-inherited abnormalities in gene development that cause the disease. Other possible causes include an imbalance of glutamate, which is a chemical messenger in the brain and spinal fluid, or a disorganized immune response, in which the afflicted person’s immune system is attacking his or her body. While the cause remains unclear, there are a few known risk factors for ALS, such as a hereditary predisposition. ALS is also more likely to occur in people between the ages of 40 and 60, and it is somewhat more common in women than men.

There is no known means of preventing ALS, but early intervention could be key to slowing down the disease’s progress. Health care providers can perform a number of tests, primarily meant to assess possible muscle weakness in different areas of the body. A physical examination may reveal signs of deterioration, as evidenced by spasms, tremors, twitching or muscle tissue loss. Other means of gauging motor control include breathing tests, swallowing studies and nerve conduction studies. Blood tests, MRIs, or CT scans can also be administered to rule out any possible underlying condition other than ALS. By using these tests, a specialist can start the patient on a medication program to help control the symptoms.

While there is no cure for ALS, there are medications that delay the progress of the disease. Riluzole is a drug designed specifically for ALS, and it has been used to slow down the spread of muscle atrophy and prolong life. There are also a number of prescriptions used to relieve symptoms that affect daily life, including anti-seizure medication and medicine typically used to treat Parkinson’s disease. Eventually, an individual with ALS may need the assistance of a wheelchair or braces, a stomach feeding tube and a mechanical respiratory aid.