NORD gratefully acknowledges Ingo Kurth, MD, Institute for Human Genetics, University Hospital Jena, Germany, for assistance in the preparation of this report.
Hereditary sensory and autonomic neuropathy type II (HSAN2) is a rare genetic disorder that usually begins in childhood by affecting the nerves that serve the lower legs and feet and the lower arms and hands. Symptoms start with inflamed fingers or toes, especially around the nails. Numbness and tingling sensations in the hands and feet may also occur. Eventually, affected individuals lose feeling (sensation) in the hands and feet. This sensory loss is due to abnormal functioning of the sensory nerves that control responses to pain and temperature and may also affect the autonomic nervous system that controls other involuntary or automatic body processes. Chronic infection of the affected areas is common and worsens as ulcers form on the fingers or the soles of the hands and feet. The loss of sensation in the hands and feet often leads to neglect of the wounds. This can become serious even leading to amputation in extreme cases if left untreated. The disorder affects many of the body’s systems, is characterized by early onset (infancy or childhood) and is transmitted genetically as an autosomal recessive trait. HSAN2 occurs due to mutations in specific genes. There are a few subtypes designated A through D, each one associated with a different gene.Introduction
The hereditary sensory and autonomic neuropathies (HSAN), also known as the hereditary sensory neuropathies, include at least six similar but distinct inherited degenerative disorders of the nervous system (neurodegenerative) that frequently progress to loss of feeling, especially in the hands and feet. Some of these disorders have several subtypes based upon the specific associated genes. Some types of HSAN are related to or identical with some forms of Charcot-Marie-Tooth disease, and others are related to or identical with familial dysautonomia (Riley-Day syndrome). The classification of the HSANs is complicated, and the experts to not always agree on it. Furthermore, HSANs are classified as broadly as peripheral neuropathies or disorders or the peripheral nervous system, which encompasses all of the nerves outside of the central nervous system (i.e. brain and spinal cord).
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