Hereditary sensory and autonomic neuropathy type I

Hereditary sensory and autonomic neuropathy type I, abbreviated HSAN I and also called hereditary sensory neuropathy type I, is a group of autosomal dominant inherited neurological diseases that affect the peripheral nervous system, particularly sensory and autonomic functions. The hallmark is a marked loss of pain and temperature sensation in the distal parts of the lower limbs, and any autonomic disturbances show up as sweating abnormalities. Onset varies between adolescence and adulthood. Because affected people cannot feel pain, minor wounds or blisters in the painless area may go unrecognized and develop into extensive, deep foot ulcerations; once infection occurs, inflammation and progressive destruction of the underlying bones may follow and may require amputation of the surrounding area. HSAN I is the most common of the five types of HSAN and can be divided into five subtypes, HSAN IA to IE. Most of the associated genes have been identified, but the molecular pathways are not fully understood, no therapeutic targets are known, gene-based therapies are not available, and supportive care is the only treatment.