Another kind of venom--this time from a Chilean tarantula--could hold the key to alleviating pain associated with chronic conditions and an extremely rare illness called inherited erythromelalgia, which is associated with the SCN9A
, the gene encoding a voltage-dependent [Na.sup.+] channel expressed in nociceptive neurons, and found that it is strongly related to pain sensation in three northern Pakistan families investigated in their study .
A Role of SCN9A
in Human Epilepsies, As a Cause of Febrile Seizures and As a Potential Modifier of DravetSyndrome.PLoS Genet.
Although there have been gene mutations that trigger nerve hyperactivity and can explain some pain conditions (e.g., SCN9A
gene mutation), genetic mutations or changes cannot explain the majority of cases of neuropathic pain.
The expression of 5 genes that are differentially identified in medullary carcinoma tested in the AMCs include calcitonin-related polypeptide [alpha] (CALCA), carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), secretogranin III (SCG3), sodium channel voltage-gated type IX [alpha] subunit (SCN9A
), and synaptotagmin IV (SYT4).
A few genetic studies have provided evidence that SCN9A
genetic mutations affecting the sodium channel [Na (v) 1.7] play the essential role in congenital indifference to pain (4,14).
Scientists already knew that mutations in another gene, SCN9A
, can cause congenital insensitivity to pain (SN: 6/30/12, p.
Congenital analgesia takes place as the result of a defect in the gene called "SCN9A
." Even the slightest defect in this gene could render it completely useless and prevent the signals transmitted to the brain from being interpreted correctly.
In a rare familial form of EM the onset is at a juvenile age and is due to a genetic mutation in the voltage-gated sodium channel alpha-subunit gene SCN9A
(OMIM 603415) , that is, selectively expressed in the nervous system within the dorsal root ganglion (DRG) and sympathetic ganglion neurons .
Studies have shown that mutations in SCN9A
, which encodes the sodium channel protein Na+ (V) 1.7 subunit, are present in some patients with inherited erythromelalgia, but are rare in noninherited cases of erythromelalgia 16].