rs112596687

chr19-38446517-T-Achr19-38446517-T-Cchr19-38446517-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000540.3(RYR1):c.677T>A(p.Met226Lys) variant causes a missense change. 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 Uncertain significance (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M226T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: RYR1 NM_000540.3 missense
• Clinical Significance: Uncertain significance reviewed by expert panel U:2 O:1
• Conservation: PhyloP100: 5.33

Genes affected

RYR1 (HGNC:10483): (ryanodine receptor 1) This gene encodes a ryanodine receptor found in skeletal muscle. The encoded protein functions as a calcium release channel in the sarcoplasmic reticulum but also serves to connect the sarcoplasmic reticulum and transverse tubule. Mutations in this gene are associated with malignant hyperthermia susceptibility, central core disease, and minicore myopathy with external ophthalmoplegia. Alternatively spliced transcripts encoding different isoforms have been described. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000540.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, RYR1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.943

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RYR1	NM_000540.3	c.677T>A	p.Met226Lys	missense_variant	8/106	ENST00000359596.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RYR1	ENST00000359596.8	c.677T>A	p.Met226Lys	missense_variant	8/106	5	NM_000540.3	A2
RYR1	ENST00000355481.8	c.677T>A	p.Met226Lys	missense_variant	8/105	1		P4
RYR1	ENST00000599547.6	c.677T>A	p.Met226Lys	missense_variant, NMD_transcript_variant	8/80	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Malignant hyperthermia, susceptibility to, 1 Uncertain:1

Uncertain significance, reviewed by expert panel

curation

ClinGen Malignant Hyperthermia Susceptibility Variant Curation Expert Panel, ClinGen

Apr 06, 2023

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 methionine with lysine at codon 226 of the RYR1 protein, p.(Met226Lys). This variant was not present in a large population database (gnomAD) at the time this variant was interpreted. This variant has been reported in three unrelated individuals who have a personal or family history of a malignant hyperthermia reaction, three of these individuals had a positive in vitro contracture test (IVCT) or caffeine halothane contracture test (CHCT) result (if the proband was unavailable for testing, a positive diagnostic test result in a mutation-positive relative was counted), PS4_Moderate (PMID:19191329, PMID:24433488, PMID:30236257). No functional studies were identified for this variant. This variant resides in a region of RYR1 considered to be a hotspot for pathogenic variants that contribute to MHS, PM1 (PMID: 21118704). A REVEL score of 0.841 supports neither a pathogenic nor a benign status for this variant. This variant has been classified as a Variant of Unknown Significance. Criteria implemented: PS4_Moderate, PM1. -

RYR1-related condition Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 14, 2023

The RYR1 c.677T>A variant is predicted to result in the amino acid substitution p.Met226Lys. This variant was reported in an individual with malignant hyperthermia, but no additional studies were done to assess its pathogenicity (Robinson et al. 2006. PubMed ID: 16917943). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

not provided Other:1

not provided, no classification provided

literature only

Leiden Muscular Dystrophy (RYR1)

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.66
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.33
Cadd	Uncertain	24
Dann	Benign	0.94
Eigen	Uncertain	0.67
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Uncertain	0.52	D
MutationAssessor	Uncertain	2.5	M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.79	T
PROVEAN	Uncertain	-2.7	D;D
REVEL	Pathogenic	0.84
Sift	Benign	0.048	D;D
Polyphen		0.99	D;D
Vest4		0.90
MutPred		0.83		Gain of ubiquitination at M226 (P = 0.03);Gain of ubiquitination at M226 (P = 0.03);
MVP		0.94
MPC		1.2
ClinPred		0.99	D
GERP RS		5.0
Varity_R		0.73
gMVP		0.74

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs112596687; hg19: chr19-38937157;