In humans, the complete loss of Asm activity in subjects exhibiting autosomally recessive SMPD1 mutations results in Niemann-Pick disease type-A, characterized by neurodegeneration of the cerebral and cerebellar cortex, basal ganglia, brain stem and spinal cord with ataxia, dysarthria and dysphagia [20]. The gene discussed is SMPD1; the disease is cerebellar ataxia.