11-64750475-AT-CG

Variant names:

• chr11-64750475-AT-CG
• NM_005609.4:c.2077_2078delATinsCG
• PYGM p.Met693Arg

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PP2 PP3

The NM_005609.4(PYGM):​c.2077_2078delATinsCG​(p.Met693Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M693T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PYGM NM_005609.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.28
• Publications: 0 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: DEFINITIVE, STRONG, SUPPORTIVE, LIMITED Submitted by: ClinGen, Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_005609.4
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 37 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: 0.046884 (below the threshold of 3.09). Trascript score misZ: 1.6804 (below the threshold of 3.09). GenCC associations: The gene is linked to glycogen storage disease V.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005609.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PYGM	NM_005609.4	MANE Select	c.2077_2078delATinsCG	p.Met693Arg	missense	N/A	NP_005600.1	P11217-1
	PYGM	NM_001164716.1		c.1813_1814delATinsCG	p.Met605Arg	missense	N/A	NP_001158188.1	P11217-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PYGM	ENST00000164139.4	TSL:1 MANE Select	c.2077_2078delATinsCG	p.Met693Arg	missense	N/A	ENSP00000164139.3	P11217-1
	PYGM	ENST00000967737.1		c.2176_2177delATinsCG	p.Met726Arg	missense	N/A	ENSP00000637796.1
	PYGM	ENST00000938870.1		c.1993_1994delATinsCG	p.Met665Arg	missense	N/A	ENSP00000608929.1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.3

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr11-64517947;