Hereditary sensory autonomic neuropathy type 1A, HSAN1A, also named HSAN1 or HSN1, is an inherited peripheral neuropathy which is caused by mutations in SPTLC1 gene. Due to the genetic mutation, patients would have a class of neurotoxic substances called deoxysphingolipids formed in their bodies that damage their sensory, motor, and autonomic nerves. Sensory nerves would be mostly affected; when motor nerves are also affected, patients are clinically diagnosed with Hereditary Sensory and Motor Neuropathy type II, also named Charcot-Marie-Tooth (CMT) type 2. Less patients develop autonomic nerve issues. Common symptoms of HSAN1A include progressive loss of sensation on feet and hands to temperature and to pain, muscle weakness and atrophy, tingling, shooting pain, etc. Blood test for deoxysphingolipids, which is the biomarker of HSAN1A, can distinguish this disease from other subtypes of CMT. The disease onset time is usually from ages 10s to 50s. Some severe cases onset in childhood. Prevalence is roughly 1:100,000. So far, there is only a few hundred patients worldwide identified with this disease. Currently some of HSAN1A patients are trying to slow down the progression of the disease by orally taking L-Serine while others are waiting for other remedies.