Hereditary neuropathies are common neurological conditions characterized by progressive loss of motor and/or sensory function. There are no effective treatments. Among the many causes of hereditary neuropathies are dominant mutations in serine palmitoyltransferase, long chain base subunit 1 (SPTLC1), which cause hereditary sensory and autonomic neuropathy type 1 (HSAN1). By incorporating L-alanine in place of L-serine, the mutant HSAN1–associated serine palmitoyltransferase generates deoxysphingolipids, which are thought to be neurotoxic. In this issue of the JCI, Garofalo and colleagues report that oral L-serine reverses the accumulation of deoxysphingolipids in humans with HSAN1 and in a transgenic mouse model. As oral L-serine reduces the severity of neuropathy in the mouse model of HSAN1, these data suggest a rational candidate therapy for this devastating condition.