NM_002863.5:c.1471C>T

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2PM5PP3_StrongPP5

The NM_002863.5(PYGL):c.1471C>T(p.Arg491Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000173 in 1,613,894 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/23 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. R491H) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

PYGL
NM_002863.5 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 10.0

Variant links:

Genes affected

PYGL (HGNC:9725): (glycogen phosphorylase L) This gene encodes a homodimeric protein that catalyses the cleavage of alpha-1,4-glucosidic bonds to release glucose-1-phosphate from liver glycogen stores. This protein switches from inactive phosphorylase B to active phosphorylase A by phosphorylation of serine residue 15. Activity of this enzyme is further regulated by multiple allosteric effectors and hormonal controls. Humans have three glycogen phosphorylase genes that encode distinct isozymes that are primarily expressed in liver, brain and muscle, respectively. The liver isozyme serves the glycemic demands of the body in general while the brain and muscle isozymes supply just those tissues. In glycogen storage disease type VI, also known as Hers disease, mutations in liver glycogen phosphorylase inhibit the conversion of glycogen to glucose and results in moderate hypoglycemia, mild ketosis, growth retardation and hepatomegaly. Alternative splicing results in multiple transcript variants encoding different isoforms.[provided by RefSeq, Feb 2011]

PYGL links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr14-50914747-C-T is described in Lovd as [Likely_pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.99

PP5

Variant 14-50914748-G-A is Pathogenic according to our data. Variant chr14-50914748-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 21329.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1, not_provided=1}. Variant chr14-50914748-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PYGL	NM_002863.5 link	c.1471C>T	p.Arg491Cys	missense_variant	Exon 12 of 20	ENST00000216392.8	NP_002854.3	P06737-1
PYGL	NM_001163940.2 link	c.1369C>T	p.Arg457Cys	missense_variant	Exon 11 of 19		NP_001157412.1	P06737-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
PYGL	ENST00000216392.8 link	c.1471C>T	p.Arg491Cys	missense_variant	Exon 12 of 20	1	NM_002863.5	ENSP00000216392.7	P06737-1
PYGL	ENST00000532462.5 link	c.1471C>T	p.Arg491Cys	missense_variant	Exon 12 of 20	1		ENSP00000431657.1	E9PK47
PYGL	ENST00000544180.6 link	c.1369C>T	p.Arg457Cys	missense_variant	Exon 11 of 19	2		ENSP00000443787.1	P06737-2

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152128

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000239

AC:

AN:

251460

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135904

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000171

AC:

AN:

1461766

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727202

show subpopulations

Gnomad4 AFR exome

AF:

0.000119

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000189

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152128

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74312

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000412

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Glycogen storage disease, type VI

Pathogenic:1Other:1

Feb 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 491 of the PYGL protein (p.Arg491Cys). This variant is present in population databases (rs113993980, gnomAD 0.007%). This missense change has been observed in individuals with clinical features of glycogen storage disease (PMID: 17705025; Invitae). ClinVar contains an entry for this variant (Variation ID: 21329). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PYGL protein function. This variant disrupts the p.Arg491 amino acid residue in PYGL. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 33763395). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

not specified

Uncertain:1

Jan 30, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: PYGL c.1471C>T (p.Arg491Cys) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.4e-05 in 251460 control chromosomes. c.1471C>T has been reported in the literature in individuals affected with Glycogen storage disease, type VI (Beauchamp_2007, Invitae)). These data suggests that this variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 17705025). ClinVar contains an entry for this variant (Variation ID: 21329). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.92

BayesDel_addAF

Pathogenic

0.44

BayesDel_noAF

Pathogenic

0.58

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.85

.;.;D

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

D;D;D

M_CAP

Pathogenic

0.49

MetaRNN

Pathogenic

0.99

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.5

.;.;H

PrimateAI

Pathogenic

0.88

PROVEAN

Pathogenic

-7.1

D;D;D

REVEL

Pathogenic

0.95

Sift

Pathogenic

0.0

D;D;D

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

.;.;D

Vest4

0.94

MutPred

0.94

Gain of catalytic residue at W492 (P = 0.0025);.;Gain of catalytic residue at W492 (P = 0.0025);

MVP

1.0

MPC

0.63

ClinPred

1.0

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.6

Varity_R

0.97

gMVP

0.91

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.25

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.25

Position offset: 2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over