Adult onset Sandhoff disease: a rare mimicker of amyotrophic lateral sclerosis.

Sandhoff disease is an under-recognized disease that may present as a lower motor neuron disorder in adulthood. We report the case of siblings presenting in their late 40s with a motor neuron disease phenotype and were misdiagnosed as amyotrophic lateral sclerosis and later found to have Sandhoff disease. Sandhoff disease should be considered in patients presenting with a slowly progressive predominately lower motor neuron disorder. A simple low-cost blood test can confirm the diagnosis.