Mutations in the SCN9A or SCN10A gene can cause<unk><unk>  neuropathy. These genes provide instructions for making pieces (the alpha subunits) of sodium channels. The SCN9A gene instructs the production of the alpha subunit for the NaV1.7 sodium channel and the SCN10A gene instructs the production of the alpha subunit for the NaV1.8 sodium channel. Sodium channels transport positively charged sodium atoms (sodium ions) into cells and play a key role in a cell's ability to generate and transmit electrical signals. The NaV1.7 and NaV1.8 sodium channels are found in nerve cells called nociceptors that transmit pain signals to the spinal cord and brain. The SCN9A gene mutations that cause<unk><unk>  neuropathy result in NaV1.7 sodium channels that do not close completely when the channel is turned off. Many SCN10A gene mutations result in NaV1.8 sodium channels that open more easily than usual. The altered channels allow sodium ions to flow abnormally into nociceptors. This increase in sodium ions enhances transmission of pain signals, causing individuals to be more sensitive to stimulation that might otherwise not cause pain. In this condition, the<unk><unk> s that extend from the nociceptors through which pain signals are transmitted (axons) degenerate over time. The cause of this degeneration is unknown, but it likely accounts for signs and symptoms such as the loss of temperature differentiation and pinprick sensation. The combination of increased pain signaling and degeneration of pain-transmitting<unk> s leads to a variable condition with signs and symptoms that can change over time. SCN9A gene mutations have been found in approximately 30 percent of individuals with<unk><unk>  neuropathy; SCN10A gene mutations are responsible for about 5 percent of cases. In some instances, other health conditions cause this disorder. Diabetes mellitus and impaired glucose tolerance are the most common diseases that lead to this disorder, with 6 to 50 percent of diabetics or pre-diabetics developing<unk><unk>  neuropathy. Other causes of this condition include a metabolic disorder called Fabry disease, immune disorders such as celiac disease or Sjogren syndrome, an inflammatory condition called sarcoidosis, and human immunodeficiency virus (HIV) infection. Recently several studies have suggested an association between autonomic<unk><unk>  neuropathy and postural orthostatic tachycardia syndrome. Other notable studies have shown a link between erythromelalgia,<unk> omyalgia, and Ehlers–Danlos Syndrome.
Small fiber peripheral neuropathy
Diabetic neuropathy
Proximal diabetic neuropathy
Vasculitic neuropathy
Autonomic neuropathy
Peripheral mononeuropathy
Tropical neuropathy
Giant axonal neuropathy