11-64753878-C-T

Variant names:

• chr11-64753878-C-T
• rs759657964
• NM_005609.4:c.1239+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1_Moderate PP5_Very_Strong

The NM_005609.4(PYGM):​c.1239+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000127 in 1,419,690 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: PYGM NM_005609.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.28
• Publications: 3 publications found

Genes affected

PYGM (HGNC:9726): (glycogen phosphorylase, muscle associated) This gene encodes a muscle enzyme involved in glycogenolysis. Highly similar enzymes encoded by different genes are found in liver and brain. Mutations in this gene are associated with McArdle disease (myophosphorylase deficiency), a glycogen storage disease of muscle. Alternative splicing results in multiple transcript variants.[provided by RefSeq, Sep 2009]

PYGM Gene-Disease associations (from GenCC):

• glycogen storage disease V

  Inheritance: AR, AD Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics, Genomics England PanelApp

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.05812574 fraction of the gene. Cryptic splice site detected, with MaxEntScore 5.5, offset of 32, new splice context is: gggGTgagg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PP5: Variant 11-64753878-C-T is Pathogenic according to our data. Variant chr11-64753878-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 569514.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PYGM	NM_005609.4	c.1239+1G>A		splice_donor_variant, intron_variant	Intron 10 of 19	ENST00000164139.4	NP_005600.1
PYGM	NM_001164716.1	c.975+1G>A		splice_donor_variant, intron_variant	Intron 8 of 17		NP_001158188.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PYGM	ENST00000164139.4	c.1239+1G>A		splice_donor_variant, intron_variant	Intron 10 of 19	1	NM_005609.4	ENSP00000164139.3
PYGM	ENST00000377432.7	c.975+1G>A		splice_donor_variant, intron_variant	Intron 8 of 17	2		ENSP00000366650.3
PYGM	ENST00000460413.1	n.316+1G>A		splice_donor_variant, intron_variant	Intron 2 of 2	3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000538 AC: 1 AN: 186020 AF XY: 0.0000100

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000129

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000127 AC: 18 AN: 1419690 Hom.: 0 Cov.: 37 AF XY: 0.0000114 AC XY: 8 AN XY: 702390

African (AFR) AF: 0.00 AC: 0 AN: 32544

American (AMR) AF: 0.00 AC: 0 AN: 38784

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25414

East Asian (EAS) AF: 0.00 AC: 0 AN: 37514

South Asian (SAS) AF: 0.00 AC: 0 AN: 80962

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50016

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5472

European-Non Finnish (NFE) AF: 0.0000147 AC: 16 AN: 1090240

Other (OTH) AF: 0.0000340 AC: 2 AN: 58744

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000409 Hom.: 0

ExAC AF: 0.00000834 AC: 1

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Glycogen storage disease, type V Pathogenic:4

Sep 02, 2021

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jul 08, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 10 of the PYGM gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in PYGM are known to be pathogenic (PMID: 8316268, 16786513). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. Disruption of this splice site has been observed in individual(s) with glycogen storage disease type V also known as McArdle disease (PMID: 16786513, 19472443). ClinVar contains an entry for this variant (Variation ID: 569514). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Dec 26, 2023

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.3
GERP RS		5.0
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.54		Position offset: -3
DS_DL_spliceai		0.98		Position offset: 1

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

Other links and lift over

dbSNP: rs759657964; hg19: chr11-64521350;