NM_000080.4:c.103T>C
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1PP5
The NM_000080.4(CHRNE):c.103T>C(p.Tyr35His) variant causes a missense change. The variant allele was found at a frequency of 0.00114 in 1,613,994 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. Y35Y) has been classified as Likely benign.
Frequency
Consequence
NM_000080.4 missense
Scores
Clinical Significance
Conservation
Publications
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ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| CHRNE | ENST00000649488.2 | c.103T>C | p.Tyr35His | missense_variant | Exon 2 of 12 | NM_000080.4 | ENSP00000497829.1 | |||
| C17orf107 | ENST00000381365.4 | c.*2174A>G | 3_prime_UTR_variant | Exon 3 of 3 | 2 | NM_001145536.2 | ENSP00000370770.3 | |||
| CHRNE | ENST00000649830.1 | c.-831T>C | 5_prime_UTR_variant | Exon 2 of 11 | ENSP00000496907.1 | |||||
| CHRNE | ENST00000575637.1 | n.-77T>C | upstream_gene_variant | 3 |
Frequencies
GnomAD3 genomes AF: 0.000651 AC: 99AN: 151998Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000640 AC: 161AN: 251424 AF XY: 0.000567 show subpopulations
GnomAD4 exome AF: 0.00119 AC: 1740AN: 1461878Hom.: 1 Cov.: 35 AF XY: 0.00109 AC XY: 796AN XY: 727242 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000651 AC: 99AN: 152116Hom.: 0 Cov.: 32 AF XY: 0.000565 AC XY: 42AN XY: 74352 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:4Uncertain:1
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The CHRNE c.103T>C; p.Tyr35His variant (rs144169073, ClinVar Variation ID: 282036), also published as Y15H, is reported in the literature in multiple individuals affected with congenital myasthenic syndrome who carried a second variant in trans (Ealing 2002, Krenn 2023, McMacken 2018, Palace 2012, Webster 2014). This variant is found in the general population with an overall allele frequency of 0.06% (180/282,748 alleles) in the Genome Aggregation Database (v2.1.1). Computational analyses predict that this variant is deleterious (REVEL: 0.897). Based on available information, this variant is considered to be likely pathogenic. References: Ealing J et al. Mutations in congenital myasthenic syndromes reveal an epsilon subunit C-terminal cysteine, C470, crucial for maturation and surface expression of adult AChR. Hum Mol Genet. 2002 Nov 15;11(24):3087-96. PMID: 12417530. Krenn M et al. The clinical and molecular landscape of congenital myasthenic syndromes in Austria: a nationwide study. J Neurol. 2023 Feb;270(2):909-916. PMID: 36308527. McMacken G et al. Congenital myasthenic syndrome with episodic apnoea: clinical, neurophysiological and genetic features in the long-term follow-up of 19 patients. J Neurol. 2018 Jan;265(1):194-203. PMID: 29189923. Palace J et al. Clinical features in a series of fast channel congenital myasthenia syndrome. Neuromuscul Disord. 2012 Feb;22(2):112-7. PMID: 21940170. Webster R et al. Fast-channel congenital myasthenic syndrome with a novel acetylcholine receptor mutation at the alpha-epsilon subunit interface. Neuromuscul Disord. 2014 Feb;24(2):143-7. PMID: 24295813. -
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In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Referred to as Y15H using alternate nomenclature; This variant is associated with the following publications: (PMID: 19544078, 21940170, 24295813, 29189923, 31980526, 17878953, 12417530, 36891870, 37091313) -
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Congenital myasthenic syndrome 4A Pathogenic:2
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This sequence change replaces tyrosine, which is neutral and polar, with histidine, which is basic and polar, at codon 35 of the CHRNE protein (p.Tyr35His). This variant is present in population databases (rs144169073, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with autosomal recessive congenital myasthenic syndrome (PMID: 12417530, 17878953, 21940170, 24295813). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. This variant is also known as Tyr15His. ClinVar contains an entry for this variant (Variation ID: 282036). 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) indicates that this missense variant is expected to disrupt CHRNE protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -
Congenital myasthenic syndrome 4C;C4225369:Congenital myasthenic syndrome 4B;C4225413:Congenital myasthenic syndrome 4A Pathogenic:1
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Congenital myasthenic syndrome 4C Pathogenic:1
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Tip-toe gait Pathogenic:1
Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -
Congenital myasthenic syndrome 4B Pathogenic:1
This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. -
Congenital myasthenic syndrome Pathogenic:1
Variant summary: CHRNE c.103T>C (p.Tyr35His), also referred to as Y15H, results in a conservative amino acid change located in the neurotransmitter-gated ion-channel ligand-binding domain (IPR006202) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00064 in 251424 control chromosomes, predominantly at a frequency of 0.0012 within the Non-Finnish European subpopulation in the gnomAD database. This frequency is not significantly higher than estimated for a pathogenic variant in CHRNE causing Congenital Myasthenic Syndrome (0.00064 vs 0.0025), allowing no conclusion about variant significance. c.103T>C has been reported in the literature as a compound heterozygous genotype in multiple individuals affected with Congenital Myasthenic Syndrome (e.g. Ealing_2002, Denning_2007, Palace_2012, Webster_2014, McMacken_2018, Clair Hou_2020). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 31980526, 17878953, 12417530, 29189923, 21940170, 24295813). Nine submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. Six submitters reported the variant as pathogenic/likely pathogenic and three as uncertain significance. Based on the evidence outlined above, the variant was classified as pathogenic. -
Congenital myasthenic syndrome 4B;C4225413:Congenital myasthenic syndrome 4A Pathogenic:1
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not specified Uncertain:1
Variant classified as Uncertain Significance - Favor Pathogenic. The p.Tyr35His variant in CHRNE has been reported in the compound heterozygous state in 6 indiv iduals with congenital myasthenic syndrome, and segregated with disease in two a ffected members of one family (reported as p.Tyr15His; Ealing 2002, Palace 2012, Webster 2014). It has also been identified in 0.1% (146/126616) of European chr omosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitut e.org; dbSNP rs144169073). In vitro functional studies provide some evidence tha t the p.Tyr35His variant may impact protein function (Ealing 2002). However, the se types of assays may not accurately represent biological function. Computation al prediction tools and conservation analysis also suggest that the variant may impact the protein, though this information is not predictive enough to determin e pathogenicity. In summary, while there is some suspicion for a pathogenic role , the clinical significance of the p.Tyr35His variant is uncertain due to its fr equency in the general population. ACMG/AMP Criteria applied: PM3_Supporting; PS 4_Moderate; PP3; PS3_Supporting; BS1_Supporting. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at