20-25259274-G-T

Variant names:

• chr20-25259274-G-T
• rs769655708
• NM_002862.4:c.281G>T

Variant summary

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

The NM_002862.4(PYGB):​c.281G>T​(p.Arg94Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,160 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R94H) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: PYGB NM_002862.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.89
• Publications: 6 publications found

Genes affected

PYGB (HGNC:9723): (glycogen phosphorylase B) The protein encoded by this gene is a glycogen phosphorylase found predominantly in the brain. The encoded protein forms homodimers which can associate into homotetramers, the enzymatically active form of glycogen phosphorylase. The activity of this enzyme is positively regulated by AMP and negatively regulated by ATP, ADP, and glucose-6-phosphate. This enzyme catalyzes the rate-determining step in glycogen degradation. [provided by RefSeq, Jul 2008]

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, 0.974

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002862.4. 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
	PYGB	NM_002862.4	MANE Select	c.281G>T	p.Arg94Leu	missense	Exon 2 of 20	NP_002853.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PYGB	ENST00000216962.9	TSL:1 MANE Select	c.281G>T	p.Arg94Leu	missense	Exon 2 of 20	ENSP00000216962.3	P11216
	PYGB	ENST00000896654.1		c.281G>T	p.Arg94Leu	missense	Exon 2 of 21	ENSP00000566713.1
	PYGB	ENST00000944638.1		c.281G>T	p.Arg94Leu	missense	Exon 2 of 21	ENSP00000614697.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152160 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251362 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152160 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74328

African (AFR) AF: 0.00 AC: 0 AN: 41426

American (AMR) AF: 0.00 AC: 0 AN: 15278

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10608

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68046

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.00 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.8	H
PhyloP100		9.9
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-5.7	D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.84		Loss of methylation at R94 (P = 0.0591)
MVP		0.99
MPC		0.88
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.84
gMVP		0.85
Mutation Taster		=33/67	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs769655708; hg19: chr20-25239910;