chr14-50910030-T-C

Variant names:

• chr14-50910030-T-C
• rs113993987
• NM_002863.5:c.2042A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_002863.5(PYGL):​c.2042A>G​(p.Lys681Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K681T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PYGL NM_002863.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.99
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• glycogen storage disease VI

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia, Genomics England PanelApp, Orphanet, Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002863.5. 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
	PYGL	NM_002863.5	MANE Select	c.2042A>G	p.Lys681Arg	missense	Exon 17 of 20	NP_002854.3
	PYGL	NM_001163940.2		c.1940A>G	p.Lys647Arg	missense	Exon 16 of 19	NP_001157412.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PYGL	ENST00000216392.8	TSL:1 MANE Select	c.2042A>G	p.Lys681Arg	missense	Exon 17 of 20	ENSP00000216392.7
	PYGL	ENST00000532462.5	TSL:1	c.2042A>G	p.Lys681Arg	missense	Exon 17 of 20	ENSP00000431657.1
	PYGL	ENST00000874287.1		c.2057A>G	p.Lys686Arg	missense	Exon 17 of 20	ENSP00000544346.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Glycogen storage disease, type VI (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.5	H
PhyloP100		8.0
PrimateAI	Pathogenic	0.88	D
PROVEAN	Uncertain	-2.7	D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.93
MutPred		0.91		Loss of ubiquitination at K681 (P = 0.0141)
MVP		0.99
MPC		0.49
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.97
gMVP		0.93
Mutation Taster		=13/87	disease causing

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

Other links and lift over

dbSNP: rs113993987; hg19: chr14-51376748;