UniProtKB/Swiss-Prot Q04844: Variant p.Leu241Phe

Acetylcholine receptor subunit epsilon
Chromosomal location: 17p13.1
Variant information

Variant position:  241
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Leucine (L) to Phenylalanine (F) at position 241 (L241F, p.Leu241Phe).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from medium size and hydrophobic (L) to large size and aromatic (F)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  0
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Involvement in disease:  Myasthenic syndrome, congenital, 4A, slow-channel (CMS4A) [MIM:605809]: A form of congenital myasthenic syndrome, a group of disorders characterized by failure of neuromuscular transmission, including pre-synaptic, synaptic, and post-synaptic disorders that are not of autoimmune origin. Clinical features are easy fatigability and muscle weakness affecting the axial and limb muscles (with hypotonia in early-onset forms), the ocular muscles (leading to ptosis and ophthalmoplegia), and the facial and bulbar musculature (affecting sucking and swallowing, and leading to dysphonia). The symptoms fluctuate and worsen with physical effort. CMS4A is a slow-channel myasthenic syndrome. It is caused by kinetic abnormalities of the AChR, resulting in prolonged AChR channel opening episodes, prolonged endplate currents, and depolarization block. This is associated with calcium overload, which may contribute to subsequent degeneration of the endplate and postsynaptic membrane. {ECO:0000269|PubMed:12141316, ECO:0000269|PubMed:27375219, ECO:0000269|PubMed:7531341, ECO:0000269|PubMed:7538206, ECO:0000269|PubMed:8872460}. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In CMS4A; mild form with variable penetrance.
Any additional useful information about the variant.

Other resources:  
Links to websites of interest for the variant.

Sequence information

Variant position:  241
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  493
The length of the canonical sequence.

The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.






Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

Chain 21 – 493 Acetylcholine receptor subunit epsilon
Transmembrane 240 – 264 Helical

Literature citations

Recessive inheritance and variable penetrance of slow-channel congenital myasthenic syndromes.
Croxen R.; Hatton C.; Shelley C.; Brydson M.; Chauplannaz G.; Oosterhuis H.; Vincent A.; Newsom-Davis J.; Colquhoun D.; Beeson D.;
Neurology 59:162-168(2002)
Cited for: VARIANTS CMS4A PRO-98 AND PHE-241;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.