What is spinobulbar muscular atrophy (SBMA), and how does it differ from ALS?

SBMA is a rare motor neuron disease in which motor neurons in the brainstem (bulbar region) and spinal cord (myelon) degenerate. As a result, similar to ALS, paralysis and muscle wasting develop in the bulbar region, the trunk, and the extremities. Unlike ALS, SBMA progresses much more slowly and is usually not associated with impaired respiratory function. Due to the slow progression of the disease, the need for nutritional and ventilatory support is generally not required. SBMA is also known by its historical name, Kennedy syndrome.