rs146931108
Variant summary
Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PP3_Moderate
The NM_000080.4(CHRNE):c.581T>C(p.Ile194Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00037 in 1,614,082 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I194F) has been classified as Uncertain significance.
Frequency
Consequence
NM_000080.4 missense
Scores
Clinical Significance
Conservation
Publications
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ACMG classification
Our verdict: Uncertain_significance. The variant received 4 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000427 AC: 65AN: 152102Hom.: 1 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.000256 AC: 64AN: 250474 AF XY: 0.000281 show subpopulations
GnomAD4 exome AF: 0.000364 AC: 532AN: 1461862Hom.: 1 Cov.: 32 AF XY: 0.000342 AC XY: 249AN XY: 727238 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000427 AC: 65AN: 152220Hom.: 1 Cov.: 33 AF XY: 0.000484 AC XY: 36AN XY: 74430 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Congenital myasthenic syndrome 4A Uncertain:2
This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 194 of the CHRNE protein (p.Ile194Thr). This variant is present in population databases (rs146931108, gnomAD 0.05%). This variant has not been reported in the literature in individuals affected with CHRNE-related conditions. ClinVar contains an entry for this variant (Variation ID: 534259). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on CHRNE protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -
Congenital myasthenic syndrome Uncertain:2
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This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
not specified Uncertain:1
Variant summary: CHRNE c.581T>C (p.Ile194Thr) results in a non-conservative amino acid change located in the Neurotransmitter-gated ion-channel ligand-binding domain (IPR006202) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00026 in 250474 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in CHRNE causing Congenital Myasthenic Syndrome (0.00026 vs 0.0025), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.581T>C in individuals affected with Congenital Myasthenic Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Seven clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Inborn genetic diseases Uncertain:1
The c.581T>C (p.I194T) alteration is located in exon 6 (coding exon 6) of the CHRNE gene. This alteration results from a T to C substitution at nucleotide position 581, causing the isoleucine (I) at amino acid position 194 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Congenital myasthenic syndrome 4C;C4225369:Congenital myasthenic syndrome 4B;C4225413:Congenital myasthenic syndrome 4A Uncertain:1
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not provided Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at