chr14-50921030-C-T

Position:

• chr14-50921030-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_002863.5(PYGL):​c.698G>A​(p.Gly233Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,850 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G233S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: PYGL NM_002863.5 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 7.88

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-50921031-C-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 14-50921030-C-T is Pathogenic according to our data. Variant chr14-50921030-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 21339.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr14-50921030-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PYGL	NM_002863.5	c.698G>A	p.Gly233Asp	missense_variant	6/20	ENST00000216392.8	NP_002854.3
PYGL	NM_001163940.2	c.596G>A	p.Gly199Asp	missense_variant	5/19		NP_001157412.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PYGL	ENST00000216392.8	c.698G>A	p.Gly233Asp	missense_variant	6/20	1	NM_002863.5	ENSP00000216392	P1
PYGL	ENST00000532462.5	c.698G>A	p.Gly233Asp	missense_variant	6/20	1		ENSP00000431657
PYGL	ENST00000544180.6	c.596G>A	p.Gly199Asp	missense_variant	5/19	2		ENSP00000443787
PYGL	ENST00000553872.1	n.499G>A		non_coding_transcript_exon_variant	1/3	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251428 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135884

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000163

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461850 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727230

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000101

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease, type VI Pathogenic:1 Other:1

not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 20, 2023	This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 233 of the PYGL protein (p.Gly233Asp). This variant is present in population databases (rs113993975, gnomAD 0.02%). This missense change has been observed in individuals with clinical features of PYGL-related conditions (PMID: 12809646; Invitae). ClinVar contains an entry for this variant (Variation ID: 21339). 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 with a positive predictive value of 80%. This variant disrupts the p.Gly233 amino acid residue in PYGL. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 31508908; Invitae). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.60
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.74	.;.;D
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	1.0	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.5	.;.;H
MutationTaster	Benign	1.0	A;A;A
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-6.5	D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.99
MutPred		0.97		Gain of phosphorylation at Y234 (P = 0.1218);.;Gain of phosphorylation at Y234 (P = 0.1218);
MVP		1.0
MPC		0.62
ClinPred		1.0	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.98
gMVP		0.97

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

LitVar

Other links and lift over

dbSNP: rs113993975; hg19: chr14-51387748;