rs113993974

chr14-50924101-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PVS1_Moderate PM2 PP3_Strong PP5

The NM_002863.5(PYGL):c.529-1G>C variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,152 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PYGL NM_002863.5 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic no assertion criteria provided P:1 O:1
• Conservation: PhyloP100: 7.91

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 Likely_pathogenic. Variant got 9 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.05149371 fraction of the gene. Cryptic splice site detected, with MaxEntScore 5.8, offset of 4, new splice context is: ctgtatccttttgcacgtAGaag. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 14-50924101-C-G is Pathogenic according to our data. Variant chr14-50924101-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 11993.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr14-50924101-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PYGL	NM_002863.5	c.529-1G>C		splice_acceptor_variant		ENST00000216392.8
PYGL	NM_001163940.2	c.427-1G>C		splice_acceptor_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PYGL	ENST00000216392.8	c.529-1G>C		splice_acceptor_variant		1	NM_002863.5	P1
PYGL	ENST00000532462.5	c.529-1G>C		splice_acceptor_variant		1
PYGL	ENST00000530336.2	n.596-1G>C		splice_acceptor_variant, non_coding_transcript_variant		1
PYGL	ENST00000544180.6	c.427-1G>C		splice_acceptor_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461152 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726942

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: no assertion criteria provided

Submissions by phenotype

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

Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 01, 1998	- -
not provided, no classification provided	literature only	GeneReviews	-	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.35
Cadd	Pathogenic	33
Dann	Uncertain	1.0
Eigen	Pathogenic	1.3
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Uncertain	0.94	D
MutationTaster	Benign	1.0	A;A;A
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.40		Position offset: -5
DS_AL_spliceai		0.99		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs113993974; hg19: chr14-51390819;