Autosomal recessive hereditary sensory and autonomic neuropathy

Autosomal recessive hereditary sensory and autonomic neuropathy (AR HSAN) is a group of rare inherited disorders affecting the peripheral sensory and autonomic nervous systems. This category encompasses several subtypes of hereditary sensory and autonomic neuropathies that follow an autosomal recessive inheritance pattern, including HSAN type II (congenital sensory neuropathy), HSAN type III (familial dysautonomia or Riley-Day syndrome), HSAN type IV (congenital insensitivity to pain with anhidrosis, or CIPA), and HSAN type V. These conditions are characterized by progressive loss of sensation, particularly to pain and temperature, which can lead to painless injuries, fractures, skin ulcers, and in some cases self-mutilation, especially in young children who are unaware of tissue damage. The autonomic nervous system is also variably affected depending on the subtype, leading to symptoms such as abnormal sweating (anhidrosis or hypohidrosis), episodic fevers, blood pressure instability, gastrointestinal dysfunction, and impaired tear production. Sensory nerve degeneration is a hallmark feature, with reduced or absent unmyelinated and small myelinated nerve fibers observed on nerve biopsy. Some subtypes present at birth or in early infancy, while others may manifest in childhood. Intellectual disability may occur in certain forms, particularly when recurrent febrile episodes cause neurological damage. Treatment is primarily supportive and symptomatic. Management focuses on preventing injuries through protective measures, careful wound care, monitoring for infections, temperature regulation, and orthopedic surveillance. For familial dysautonomia (HSAN III), specific interventions may include management of autonomic crises, artificial tears, and feeding support. No curative therapies are currently available, though research into gene-targeted approaches is ongoing. A multidisciplinary care team including neurologists, orthopedists, dermatologists, and pain specialists is typically recommended.

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