SPTLC1 and hereditary sensory and autonomic neuropathy type 1: Pathogenic variants in the cytoplasmic domains of SPTLC1 and SPTLC2 can cause hereditary sensory and autonomic neuropathy type 1 (HSAN1) and macular telangiectasia type 2 by abnormally increasing deoxy‐sphingolipid levels.24, 25, 26, 27, 28, 29