ClinVar Genomic variation as it relates to human health

This pathogenicity assessment is relevant only for malignant hyperthermia susceptibility (MHS) inherited in an autosomal dominant pattern. Variants in RYR1 can also cause other myopathies inherited in an autosomal dominant pattern or in an autosomal recessive pattern. Some of these disorders may predispose individuals to malignant hyperthermia. RYR1 variants may also contribute to a malignant hyperthermia reaction in combination with other genetic and non-genetic factors and the clinician needs to consider such factors in making management decisions. This sequence variant predicts a substitution of serine with phenylalanine at codon 2776 of the RYR1 protein p.(Ser2776Phe). The maximum allele frequency for this variant among the six major gnomAD populations is NFE: 0.00145, this is considered to be more common than expected for a pathogenic variant causing autosomal dominant MHS, BS1. This variant has been reported in two unrelated individuals who have a personal or family history of a malignant hyperthermia reaction, both of these individuals had a positive in vitro contracture test (IVCT) or caffeine halothane contracture test (CHCT) result (when the proband was unavailable for testing a positive diagnostic test result in a mutation positive relative was counted), ( PMID:21965348, PMID:30236257 ). However, the high MAF in the NFE population in gnomAD precludes the use of PS4. No functional studies were identified for this variant. This variant does not reside in a hotspot for pathogenic variants that contribute to MHS. A REVEL score of 0.693 does not support a pathogenic or a benign status. This variant has been classified as Likely Benign. Criteria implemented: BS1.

Identified in individuals with RYR1-related neuromuscular disorders; however, in these cases S2776F has been found in conjunction with other potentially pathogenic variants (Fiszer et al., 2015; Snoeck et al., 2015), or as a single variant that was found to be inherited from an unaffected parent (Dowling et al., 2011; Snoeck et al., 2015).; In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 25658027, 21965348, 25960145, 22705209, 27535533, 30788618, 32054689, 24195946, 21514828)

RYR1: PP3

Variant identified in a genome or exome case(s) and assessed due to predicted null impact of the variant or pathogenic assertions in the literature or databases. Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: Reported in healthy individuals; ExAC: 0.1% (67/59798) European chromosomes; ClinVar: 1 VUS; ML: Frequent for disease

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases allowed determination this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign.

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign.

The RYR1 c.8327C>T variant is predicted to result in the amino acid substitution p.Ser2776Phe. This variant was reported in two Malignant Hyperthermia (MH) patients and one patient with King Denborough syndrome (Broman et al. 2011. PubMedID: 21965348; Dowling et al. 2011. PubMedID: 21514828; Gonsalves et al. 2013. PubMedID: 24195946; Fiszer et al. 2015. PubMedID: 25658027). However, the pathogenicity was not clearly established in any of these cases and the asymptomatic mother of the King Denborough patient was heterozygous for the c.8327C>T variant. This suggests the c.8327C>T is less likely to be pathogenic for autosomal dominant RYR1-related disorders, but could be causative for a recessive RYR1-related myopathy. The c.8327C>T variant has been reported in control individuals of European ancestry with an allele frequency of about 0.1% (http://gnomad-old.broadinstitute.org/variant/19-38995965-C-T/). In summary, the clinical significance of the c.8327C>T variant is currently uncertain due to the absence of conclusive evidence.

European Non-Finnish population allele frequency is 0.1329%% (rs147707463, 186/128,314 alleles, 0 homozygotes in gnomAD v2.1). Based on the classification scheme RMH Modified ACMG/AMP Guidelines v1.5.1, this variant is classified as LIKELY BENIGN. Following criteria are met: BS1