HSAN2B is a neurodegenerative disorder of the peripheral nervous system. It is characterized by the impaired perception of pain, temperature and touch in the distal extremities, particularly in the lower limbs. Neuropathic skin causes hyperkeratosis and leads to ulcerations and infections. Patients suffer from osteomyelitis as well as acroosteolysis, and eventually the digits of the hands and feet undergo self-amputation. Autonomic disturbances include urinary incontinence, hyperhidrosis and tonic pupils.
The condition has an onset in the first or second decade of life, often before puberty. It is phenotypically variable, even between affected members of the same family. HSAN2B is a progressive disorder but there is limited information regarding its prognosis. Compared to other subsets of hereditary sensory and autonomic neuropathy 2, HSAN2B has been noted to have more severe autonomic dysfunction.
Diagnosis of the disorder is based on clinical findings, neurologic examinations, nerve conduction studies and genetic analysis of the FAM134B gene. There is currently no cure for the condition and treatment is focused on symptomatic care. Patients require a multi-disciplinary team of clinicians, surgeons and physical therapists to monitor their condition and prevent secondary complications.