BDNF and hereditary sensory and autonomic neuropathy: Various cellular processes can be affected, including sodium channel activity,1,2 sphingolipid metabolism,3,4 membrane dynamics,5–7 axonal transport,8,9 neurotrophin signalling,10,11 epigenetic regulation12 or cytoskeletal architecture.13 Because of the rarity of CIP/HSAN disorders, knowledge of these conditions is limited and diagnosis is often delayed or incorrect resulting in a diagnostic odyssey.