Low Levels of SMN Increase Risk, Severity of ALS

The more SMN (survival of motor neuron) protein one has, apparently, the better it is for motor neurons, the nerve cells in the brain and spinal cord that control movement and degenerate in amyotrophic lateral sclerosis (ALS).

A Dutch study published in the Sept. 27 issue of Neurology shows that relatively low levels of SMN, such as those found in carriers of spinal muscular atrophy, a disease affecting the motor neurons in the spinal cord, increase the risk of developing ALS, and shorten survival time in those who already have the disease.

Jan Veldink at University Medical Center Utrecht says that, even with low SMN levels, the risk of developing ALS remains small. With low SMN, it increases from about 1.5 per 100,000 to about six per 100,000.

He said the main implication of the findings isn’t that people with low SMN should worry about developing ALS, but that understanding SMN’s functions may shed new light on the mechanisms underlying ALS development and progression.