The CHRNA2 gene provides instructions for making one part (subunit) of a larger protein complex called a neuronal nicotinic acetylcholine receptor (nAChR). Each nAChR complex is made up of a combination of five subunits, usually two alpha (α) and three beta (β) subunits.  Many different combinations are possible, and the characteristics of each nAChR complex depend on its specific subunits. The CHRNA2 gene is responsible for producing a subunit known as α2. Little is known about the specific function of nAChR proteins made with this subunit.

In the brain, nAChR proteins are widely distributed and play an important role in chemical signaling between nerve cells (neurons).  The nAChR acts as a channel, allowing charged atoms (ions), including calcium, sodium, and potassium, to cross the cell membrane.  These channels open when they attach to a chemical messenger (neurotransmitter) called acetylcholine.  The channels also open in response to nicotine, the addictive substance in tobacco.

Communication between neurons depends on neurotransmitters, which are released from one neuron and taken up by neighboring neurons. The release and uptake of these chemicals are tightly regulated to ensure that signals are passed efficiently and accurately between neurons. Researchers believe that nAChR channels play an important role in controlling the normal release and uptake of neurotransmitters.

A wide range of brain functions depend on nAChR channels, including sleep and arousal, fatigue, anxiety, attention, pain perception, and memory. The channels are also active before birth, which suggests that they are involved in early brain development.

Tests Listed in the Genetic Testing Registry

• Tests of CHRNA2

Scientific Articles on PubMed

• PubMed

Catalog of Genes and Diseases from OMIM

• CHOLINERGIC RECEPTOR, NEURONAL NICOTINIC, ALPHA POLYPEPTIDE 2; CHRNA2

Gene and Variant Databases

• NCBI Gene
• ClinVar

• Aridon P, Marini C, Di Resta C, Brilli E, De Fusco M, Politi F, Parrini E, Manfredi I, Pisano T, Pruna D, Curia G, Cianchetti C, Pasqualetti M, Becchetti A, Guerrini R, Casari G. Increased sensitivity of the neuronal nicotinic receptor alpha 2 subunit causes familial epilepsy with nocturnal wandering and ictal fear. Am J Hum Genet. 2006 Aug;79(2):342-50. doi: 10.1086/506459. Epub 2006 Jun 26. Citation on PubMed or Free article on PubMed Central
• Arneric SP, Holladay M, Williams M. Neuronal nicotinic receptors: a perspective on two decades of drug discovery research. Biochem Pharmacol. 2007 Oct 15;74(8):1092-101. doi: 10.1016/j.bcp.2007.06.033. Epub 2007 Jun 26. Citation on PubMed
• Combi R, Ferini-Strambi L, Tenchini ML. CHRNA2 mutations are rare in the NFLE population: evaluation of a large cohort of Italian patients. Sleep Med. 2009 Jan;10(1):139-42. doi: 10.1016/j.sleep.2007.11.010. Epub 2008 Jan 28. Citation on PubMed
• Gu W, Bertrand D, Steinlein OK. A major role of the nicotinic acetylcholine receptor gene CHRNA2 in autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is unlikely. Neurosci Lett. 2007 Jul 5;422(1):74-6. doi: 10.1016/j.neulet.2007.06.006. Epub 2007 Jun 8. Citation on PubMed
• Marini C, Guerrini R. The role of the nicotinic acetylcholine receptors in sleep-related epilepsy. Biochem Pharmacol. 2007 Oct 15;74(8):1308-14. doi: 10.1016/j.bcp.2007.06.030. Epub 2007 Jun 23. Citation on PubMed