基因产物：钠离子通道α9亚基。

蛋白功能：主要在周围神经系统中表达，可与钠离子通道β亚基组成电压门控性钠通道，在痛觉信号转导中发挥重要作用[147]。

相关疾病：热性惊厥（AD）[1]； 遗传性癫痫伴热性惊厥附加症 （AD）；原发性红斑性肢痛症（AD）[2]；小纤维神经病（AD）[3]；常染色体隐性遗传性感觉神经病2D型（AR）[4；先天性痛觉不敏感（AR）[5]；阵发性剧痛症（AD）[6]； Dravet 综合征 （多数需要和SCN1A或其它基因共同作用发病）（AD）[1]。 


参考文献

1. Singh, N.A., et al., A role of SCN9A in human epilepsies, as a cause of febrile seizures and as a potential modifier of Dravet syndrome.PLoS Genet, 2009. 5(9): p. e1000649.
2. Michiels, J.J., et al., Autosomal dominant erythermalgia associated with a novel mutation in the voltage-gated sodium channel alpha subunit Nav1.7.Arch Neurol, 2005. 62(10): p. 1587-90.
3. Faber, C.G., et al., Gain of function Nanu1.7 mutations in idiopathic small fiber neuropathy.Ann Neurol, 2012. 71(1): p. 26-39.
4. Yuan, J., et al., Hereditary sensory and autonomic neuropathy type IID caused by an SCN9A mutation.Neurology, 2013. 80(18): p. 1641-9.
5. Cox, J.J., et al., An SCN9A channelopathy causes congenital inability to experience pain.Nature, 2006. 444(7121): p. 894-8.
6. Fertleman, C.R., et al., SCN9A mutations in paroxysmal extreme pain disorder: allelic variants underlie distinct channel defects and phenotypes.Neuron, 2006. 52(5): p. 767-74.