rs143177272

Variant names:

Your query was ambiguous. Multiple possible variants found:

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PP2PP3_Strong

The NM_005609.4(PYGM):c.2446C>T(p.Arg816Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000991 in 1,614,036 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R816H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000099 ( 0 hom. )

Consequence

PYGM
NM_005609.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:4

Conservation

PhyloP100: 3.40

Publications

6 publications found

Variant links:

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

PYGM links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

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

MetaRNN computational evidence supports a deleterious effect, 0.971

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PYGM	NM_005609.4	MANE Select	c.2446C>T	p.Arg816Cys	missense	Exon 20 of 20	NP_005600.1
	PYGM	NM_001164716.1		c.2182C>T	p.Arg728Cys	missense	Exon 18 of 18	NP_001158188.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
PYGM	ENST00000164139.4	TSL:1 MANE Select	c.2446C>T	p.Arg816Cys	missense	Exon 20 of 20	ENSP00000164139.3
PYGM	ENST00000377432.7	TSL:2	c.2182C>T	p.Arg728Cys	missense	Exon 18 of 18	ENSP00000366650.3
PYGM	ENST00000483742.1	TSL:2	n.1799C>T		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes

AF:

0.000105

AC:

AN:

152144

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000206

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000477

AC:

AN:

251484

AF XY:

0.0000515

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.0000924

Gnomad NFE exome

AF:

0.0000703

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000985

AC:

144

AN:

1461892

Hom.:

Cov.:

AF XY:

0.000102

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.000101

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000374

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000121

AC:

134

AN:

1112010

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000105

AC:

AN:

152144

Hom.:

Cov.:

AF XY:

0.0000942

AC XY:

AN XY:

74322

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41438

American (AMR)

AF:

0.00

AC:

AN:

15276

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000206

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.512

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000173

Hom.:

Bravo

AF:

0.000117

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Glycogen storage disease, type V

Uncertain:2

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Jun 26, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 816 of the PYGM protein (p.Arg816Cys). This variant is present in population databases (rs143177272, gnomAD 0.009%). This variant has not been reported in the literature in individuals affected with PYGM-related conditions. ClinVar contains an entry for this variant (Variation ID: 281389). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Not Available"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Not Available"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Tip-toe gait

Pathogenic:1

Oct 26, 2021

Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Toe Walking has various causes, ranging from idiopathic or habitual reasons to an underlying neuromuscular disease. The most observed form of toe walking is idiopathic toe walking (ITW) - a diagnosis of exclusion. ITW occurs in about 5% of children after their second birthday and is a common problem in pediatric orthopedics. In about 70% of these cases, there is spontaneous remission within six months of the onset of ITW. If the toe walk persists, one can assume the presence of a non-idiopathic form of toe walk (n-ITW). In n-ITW, the causes of the abnormal gait are neurological or myogenic. Differential diagnoses such as infantile cerebral palsy, muscular dystrophy, spinal amyotrophy and hereditary motor-sensory neuropathy as well as rare metabolic disorders of the musculature must be considered (Pomarino et al., 2018). In our clinical ITW consultation, we screen children with n-ITW for a genetic form of tiptoe gait using next generation sequencing for gene variants in 49 genes. These are genes in which gene variants can lead to neuromuscular diseases in which an association with toe-tapping gait has been reported or can be suspected due to patients’ clinical symptoms. To the best of our knowledge, this is the first study in which several patients with toe walking displayed heterozygosity for pathogenic or likely pathogenic PYGM mutations and mild symptoms of the metabolic muscle disease McArdle. The findings of our research are in line with recently published observations in heterozygous family members patients with McArdle disease. We should mention that some of the patients in our cohort harbored heterozygous variants in other genes of our gene panel. However, the numbers in this study were too small to workout any resulting combined genetic effects. It is concluded that genetic conditions can contribute to the development of toe walking. Apparently, even a slight genetic weakening of the muscles can lead to changes to the gait pattern. Future studies must show how the pathomechanism can be explained for the PYGM variants and whether there are new therapeutic approaches to be developed based on this research.

Inborn genetic diseases

Uncertain:1

Apr 21, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.2446C>T (p.R816C) alteration is located in exon 20 (coding exon 20) of the PYGM gene. This alteration results from a C to T substitution at nucleotide position 2446, causing the arginine (R) at amino acid position 816 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

not provided

Uncertain:1

Jun 11, 2015

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.74

BayesDel_addAF

Pathogenic

0.40

BayesDel_noAF

Pathogenic

0.52

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.89

Eigen

Pathogenic

0.72

Eigen_PC

Uncertain

0.56

FATHMM_MKL

Uncertain

0.95

LIST_S2

Pathogenic

1.0

M_CAP

Pathogenic

0.38

MetaRNN

Pathogenic

0.97

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

4.2

PhyloP100

3.4

PrimateAI

Pathogenic

0.83

PROVEAN

Pathogenic

-7.1

REVEL

Pathogenic

0.96

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.91

MVP

0.99

MPC

0.99

ClinPred

1.0

GERP RS

3.5

Varity_R

0.89

gMVP

0.91

Mutation Taster

=13/87

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over