Hereditary sensory and autonomic neuropathy type I

Hereditary Sensory and Autonomic Neuropathy Type I (HSAN I), also known as Hereditary Sensory Neuropathy Type I (HSN I), is a rare genetic disorder characterized by a loss of sensory functions and autonomic nervous system dysfunction. This condition is part of a group of disorders known as Hereditary Sensory and Autonomic Neuropathies (HSAN), which affect the peripheral nervous system. HSAN I specifically impacts sensory and autonomic neurons, leading to a wide range of symptoms, including insensitivity to pain, temperature sensation abnormalities, and autonomic nervous system problems such as abnormal sweating and blood pressure regulation.

Symptoms and Signs

The primary symptoms of HSAN I include a reduced ability to feel pain and temperature changes, leading to repeated injuries and wounds that the person may not notice. Over time, these injuries can result in severe complications, such as infections and ulcers. Autonomic dysfunction in HSAN I may manifest as disturbances in sweating, blood pressure regulation, and gastrointestinal motility, among other symptoms.

Causes

HSAN I is caused by mutations in specific genes that are inherited in an autosomal dominant manner. These genetic mutations lead to the degeneration of sensory and autonomic neurons. The most commonly implicated gene in HSAN I is the Serine Palmitoyltransferase, Long Chain Base Subunit 1 (SPTLC1) gene, although mutations in other genes have also been associated with the condition.

Diagnosis

Diagnosis of HSAN I involves a comprehensive clinical evaluation, detailed patient history, and the use of genetic testing to identify mutations in the SPTLC1 gene or other related genes. Nerve conduction studies and skin biopsies may also be utilized to assess the extent of nerve damage and loss of nerve fibers.

Treatment

There is currently no cure for HSAN I, and treatment focuses on managing symptoms and preventing complications. This may include regular monitoring and care of the skin and feet to prevent injuries and infections, pain management strategies, and addressing autonomic symptoms. In some cases, physical therapy and the use of orthotic devices may be recommended to improve mobility and function.

Prognosis

The prognosis for individuals with HSAN I varies depending on the severity of symptoms and the effectiveness of management strategies. Early diagnosis and intervention can help prevent complications and improve quality of life.

NIH genetic and rare disease info

• NIH info on Hereditary sensory and autonomic neuropathy type I

Hereditary sensory and autonomic neuropathy type I is a rare disease.