chr19-38546515-C-T
Variant summary
Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP2PP3_ModeratePP5
The NM_000540.3(RYR1):c.12083C>T(p.Ser4028Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000540.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 6 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 29
GnomAD4 exome Cov.: 31
GnomAD4 genome Cov.: 29
ClinVar
Submissions by phenotype
not provided Pathogenic:2Uncertain:2
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Central core myopathy Pathogenic:1Uncertain:1
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The observed missense variant c.12083C>T (p.Ser4028Leu) in RYR1 gene has been reported previously in heterozygous state in multiple individuals affected with congenital myopathy, with a susceptibility to malignant hyperthermia (Dai et al. 2015; Biancalana et al. 2021). This variant is reported to segregate with the disease in families with dominant disease transmission, and may also occur de novo (Biancalana et al. 2021). Experimental evidence shows that this variant causes channel oxidation and reduces RyR1-calstabin1 binding, and causes leaky channel behavior which is known to cause muscle dysfunction (Kushnir et al. 2020; Yuan et al. 2021). The p.Ser4028Leu variant is absent in gnomAD Exomes database. This variant has been submitted to the ClinVar database as Uncertain Significance / Likely Pathogenic / Pathogenic. Multiple lines of computational evidence (SIFT - damaging; Polyphen - probably damaging; MutationTaster - disease causing) predict a damaging effect on protein structure and function for this variant. The reference amino acid at this position on RYR1 is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The amino acid Ser at position 4028 is changed to a Leu changing protein sequence and it might alter its composition and physico-chemical properties. For these reasons, this variant has been classified as Pathogenic. -
Congenital multicore myopathy with external ophthalmoplegia Pathogenic:1
Variant summary: RYR1 c.12083C>T (p.Ser4028Leu) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251464 control chromosomes (gnomAD). c.12083C>T has been reported in the literature in multiple individuals affected with Congenital Myopathy and was shown to segregate with the disease in dominant families or to occur de novo in sporadic cases (e.g. Dai_2015, Kushnir_2020, Biancalana_2021, Natera-de Benito_2021). These data indicate that the variant is very likely to be associated with disease. Experimental evidence evaluating an impact on protein function demonstrated the variant increased channel oxidation and reduced RyR1-calstabin1 binding, and was consistent with leaky channel behavior (Kushnir_2020, Yuan_2021). Three ClinVar submitters (evaluation after 2014) cite the variant as pathogenic/likely pathogenic and one ClinVar submitter (evaluation after 2014) cites it as uncertain significance. Based on the evidence outlined above, the variant was classified as pathogenic. -
Inborn genetic diseases Pathogenic:1
The c.12083C>T (p.S4028L) alteration is located in coding exon 88 of the RYR1 gene. This alteration results from a C to T substitution at nucleotide position 12083, causing the serine (S) at amino acid position 4028 to be replaced by a leucine (L). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been observed in multiple individuals with clinical features of RYR1-related myopathy, including several de novo occurrences (Dai, 2015; Kushnir, 2020; Biancalana, 2021). This amino acid position is highly conserved in available vertebrate species. Experimental evidence derived from studies on muscle biopsies of patients with the variant, demonstrated increased channel oxidation and reduced RyR1-calstabin1 binding, and increased sensitivity to Ca2+-dependent activation consistent with leaky channel behavior (Kushnir, 2020; Yuan, 2021). The in silico prediction for this alteration is inconclusive. Based on the available evidence, this alteration is classified as pathogenic. -
RYR1-related disorder Pathogenic:1
This sequence change replaces serine, which is neutral and polar, with leucine, which is neutral and non-polar, at codon 4028 of the RYR1 protein (p.Ser4028Leu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with autosomal dominant congenital myopathy (PMID: 25987458, 27447704; Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 201152). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt RYR1 protein function with a negative predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -
Malignant hyperthermia, susceptibility to, 1 Pathogenic:1
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Centronuclear myopathy Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at