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 glutamic acid with lysine at codon 2764 of the RYR1 protein, p.(Glu2764Lys). The maximum allele frequency for this variant among the six major gnomAD populations is EAS: 0.000109, a frequency consistent with pathogenicity for MHS. To our knowledge, this variant has not been reported in any individuals with a personal or family history of an MH episode and a positive in vitro contracture test (IVCT) or caffeine halothane contracture test (CHCT). 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 0.842 supports neither a pathogenic nor a benign status for this variant. This variant has been classified as a Variant of Unknown Significance. No criteria implemented.

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 1 MH proband, structural analysis suggests variant falls on same face of a phosphorylation as other predicted pathogenic variants.

The RYR1 c.8290G>A variant is predicted to result in the amino acid substitution p.Glu2764Lys. This variant was previously reported in a patient with malignant hyperthermia and in another individual with primary periodic paralysis; however, pathogenicity was not established with segregation or functional analysis (Galli et al. 2006. PubMed ID: 16835904; Luo et al. 2019. PubMed ID: 31068157). This variant is reported in 0.011% of alleles in individuals of East Asian descent in gnomAD (http://gnomad.broadinstitute.org/variant/19-38995701-G-A). This variant is interpreted as uncertain in ClinVar by the ClinGen Malignant Hyperthermia Susceptibility Expert Panel (https://www.ncbi.nlm.nih.gov/clinvar/variation/133221/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence.

This missense variant replaces glutamic acid with lysine at codon 2764 of the RYR1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with malignant hyperthermia susceptibility (PMID: 16835904). This variant has been identified in 3/251480 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance.

Reported previously as a heterozygous variant in an individual with repeated episodes of generalized normokalemic paralysis (PMID: 31068157); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 22705209, 35677449, 31068157, 16835904, 12668474)