HSAN2 - Genetics Home Reference

Hereditary sensory and autonomic neuropathy type II
(often shortened to HSAN2)

Reviewed May 2011

What is HSAN2?

Hereditary sensory and autonomic neuropathy type II (HSAN2) is a condition that primarily affects the sensory nerve cells (sensory neurons), which transmit information about sensations such as pain, temperature, and touch. These sensations are impaired in people with HSAN2. In some affected people, the condition may also cause mild abnormalities of the autonomic nervous system, which controls involuntary body functions such as heart rate, digestion, and breathing. The signs and symptoms of HSAN2 typically begin in infancy or early childhood.

The first sign of HSAN2 is usually numbness in the hands and feet. Soon after, affected individuals lose the ability to feel pain or sense hot and cold. People with HSAN2 often develop open sores (ulcers) on their hands and feet. Because affected individuals cannot feel the pain of these sores, they may not seek treatment right away. Without treatment, the ulcers can become infected and may lead to amputation of the affected area. Unintentional self-injury is common in people with HSAN2, typically by biting the tongue, lips, or fingers. These injuries may lead to spontaneous amputation of the affected areas. Affected individuals often have injuries and fractures in their hands, feet, limbs, and joints that go untreated because of the inability to feel pain. Repeated injury can lead to a condition called Charcot joints, in which the bones and tissue surrounding joints are destroyed.

The effects of HSAN2 on the autonomic nervous system are more variable. Some infants with HSAN2 have trouble sucking, which makes it difficult for them to eat. People with HSAN2 may experience episodes in which breathing slows or stops for short periods (apnea); digestive problems such as the backflow of stomach acids into the esophagus (gastroesophageal reflux); or slow eye blink or gag reflexes. Affected individuals may also have weak deep tendon reflexes, such as the reflex being tested when a doctor taps your knee with a hammer.

Some people with HSAN2 lose a type of taste bud on the tip of the tongue called lingual fungiform papillae and have a diminished sense of taste.

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HSAN2 - Genetics Home Reference