Cholinergic Receptor, Nicotinic, Epsilon Polypeptide

Alternative Names

  • Acetylcholine Receptor, Muscle, Epsilon Subunit
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OMIM Number




Uniprot ID



10,907 bases

No. of Exons


No. of isoforms


Protein Name

Acetylcholine receptor subunit epsilon

Molecular Mass

54697 Da

Amino Acid Count


Genomic Location


Gene Map Locus


The CHRNE gene encodes the epsilon subunit of the acetycholine receptor protein. Acetylcholine receptor is a ligand gated ion channel made up of alpha, beta, gamma, delta and epsilon subunits. The receptor changes subunit composition shortly after birth when the epsilon subunit replaces the gamma subunit seen in embryonic receptors. Mutations in the CHRNE gene result in congenital myasthenic syndrome, a disease characterized by muscle weakness.

Mutations in CHRNE can affect acetylcholine receptor functioning in three ways. It can produce a prolonged opening of the acetylcholine receptor channel resulting in slowed decay of end plate currents, calcium overload of the synaptic region and ultimately myopathy of the endplate and postsynaptic membrane. This is classified as congenital myasthenic syndrome 4A, slow channel (CMS4A). In congenital myasthenic syndrome 4B, fast channel (CMS4B), mutations result in brief opening of the channel, producing a rapid decay in endplate current, failure to achieve threshold depolarisation and subsequently, failure to fire an action potential. Mutations can also cause deficiency of acetylcholine at the endplate resulting in low amplitude of the miniature endplate potential and current. This is classified as congenital myasthenic syndrome 4C, associated with acetylcholine receptor deficiency (CMS4C).

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_000080.4:c.1314G>CUnited Arab EmiratesNC_000017.11:g.4899013C>GUncertain SignificanceUncertain SignificanceNG_008029.2:g.9063G>C; NM_000080.4:c.1314G>C; NP_000071.1:p.Glu438Asp7729956802032499

Other Reports

Saudi Arabia

Salih et al. (2011) reported 3 CMS affected brothers of a consanguineous family. By 2-3 months of age, the oldest sibling suffered from bilateral ptosis, choking, decreased feeding and failure to thrive and had several episodes of respiratory failure. The younger two siblings had milder symptoms and all 3 patients started pyridostigmine by 5 months of age. The patients, aged 21, 17 and 13 years, showed normal development with intact cognitive function. Patients were found to have bilateral ptosis, reduced eye movements, extremely slow and hypometric saccades with weak orbicularis ocular muscle. Genetic testing revealed a homozygous duplication 123-127dupCTCAC in exon 2 of the CHRNE gene in all 3 siblings. The mutation is speculated to result in the conversion of Leu-Asn-Glu to Pro-His-Stop at positions 43-45 and truncation of the epsilon subunit in its extracellular domain. This would result in severe deficiency of the mature acetyl choline receptor. Both parents were found to be heterozygous for the mutation but it was not found in 50 ethnically matched controls. The authors stressed the importance of determining the causal mutation in CMS cases before administering medication.

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