Lou Gehrig Disease or Amyotrophic Lateral Sclerosis (ALS) is the most common progressive degenerative motor neuron disease.  It was first described by French neurologist Jean-Martin Charcot in 1869, but didn’t gain popular recognition until 1939 when famed Yankee Lou Gehrig was diagnosed with the disease.  In the US, 5600 people are diagnosed each year and it is estimated that 16,000 Americans may have the disease at any given time. 

How does ALS present itself?

ALS most commonly presents between 40-60 years of age.  It is the gradual, slowly progressive, painless weakness in 1 or more regions in the body, without changes in the ability to feel, and no other cause immediately evident. 

About 75% of patients begin with limb involvement, either upper or lower limbs affected.  Lower limb involvement usually presents as tripping, or stumbling.  As the disease progresses, muscle strength is lost as is coordination resulting in increased difficulty in complex movements and dexterity.  Immobility may predispose the patient to the development of painful joint contractures. Muscle cramps are common. In some patients, persistent stiffness or cramping of muscles may stress the related joints and the back.

Patients may also develop difficulties with speech and swallowing.  Some develop behavioral manifestations of their disease, involving: exaggerated emotional responses and difficulty with executive functions.  During this progression some systems remain preserved.  For instance, most retain eye movement, bowel and bladder control.  Similarly, feeling sensation is usually persevered as well.  

What causes ALS?

The cause is unknown in the majority of people, and there is no single cause explaining its entire pathology. The most widely accepted hypothesis regarding the cause of sporadic ALS is that interactions between genetic, environmental, and age-dependent risk factors trigger disease onset.  Smoking however is the only identifiable environmental risk factor to date.  A toxin found in the Nuts of the Cycas tree has also been implicated in the development of a form of ALS in Guam

It is estimated that 5-10% of cases are familial with a standard and clear inheritance pattern.  The disease is transmitted in an autosomal dominant fashion in most cases, meaning if your parent has the disease you have a 50% chance of having the disease.  In general, mean age at onset is 10-20 years younger than patients without a family history.