Hereditary Sensory Neuropathy Type 1

Hereditary sensory neuropathy type 1 (HSN1) is a neurological condition characterized by nerve abnormalities in the legs and feet. Many people with this condition have tingling, weakness, and a reduced ability to feel pain and sense hot and cold. Some affected people do not lose sensation, but instead feel shooting pains in their legs and feet. As HSN1 progresses, sensory problems can affect the hands, arms, shoulders, and abdomen. In rare cases, people with this condition develop sensorineural hearing loss. Symptoms of HSN1 typically begin during a person's teens or twenties and worsen over time.  HSN1 is caused by mutations in any of several genes, depending on the form of HSN1 (HSN1A is caused by mutations in the SPTLC1 gene; HSN1B is linked to a gene located in chromosome 3; HSN1C is caused by mutations in the SPTLC2 gene; HSN1D is caused by mutations in the ATL1 gene and HSN1E is caused by mutations in DNMT1 gene. All forms of HSN1 are inherited in an autosomal dominant manner. If symptoms are treated properly, the condition does not appear to affect life expectancy.