Clinically, patients with mutations in SPTLC1 or SPTLC2 are phenotypically indistinguishable and mutations in both genes have been suggested to cause HSN-1 via the same mechanism of dysregulated sphingolipid metabolism (Rotthier et al., 2012). The gene discussed is SPTLC1; the disease is hereditary sensory and autonomic neuropathy type 1.