20-25296515-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002862.4(PYGB):c.2525G>A(p.Arg842Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000285 in 1,612,732 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000030 (0 hom.)
• Consequence: PYGB NM_002862.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.462

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]

ABHD12 (HGNC:15868): (abhydrolase domain containing 12, lysophospholipase) This gene encodes an enzyme that catalyzes the hydrolysis of 2-arachidonoyl glycerol (2-AG), the main endocannabinoid lipid transmitter that acts on cannabinoid receptors, CB1 and CB2. The endocannabinoid system is involved in a wide range of physiological processes, including neurotransmission, mood, appetite, pain appreciation, addiction behavior, and inflammation. Mutations in this gene are associated with the neurodegenerative disease, PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and cataract), resulting from an inborn error of endocannabinoid metabolism. Alternatively spliced transcript variants encoding different isoforms have been noted for this gene.[provided by RefSeq, Jan 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.13075238).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PYGB	NM_002862.4	c.2525G>A	p.Arg842Gln	missense_variant	20/20	ENST00000216962.9
ABHD12	NM_015600.5	c.1158-1485C>T		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PYGB	ENST00000216962.9	c.2525G>A	p.Arg842Gln	missense_variant	20/20	1	NM_002862.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152138 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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000160 AC: 4 AN: 249788 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 135036

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000580

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000886

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000301 AC: 44 AN: 1460594 Hom.: 0 Cov.: 31 AF XY: 0.0000317 AC XY: 23 AN XY: 726528

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000126

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000306

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152138 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74312

Gnomad4 AFR AF: 0.00

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: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000392 Hom.: 0

Bravo AF: 0.0000113

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 12, 2022

The c.2525G>A (p.R842Q) alteration is located in exon 20 (coding exon 20) of the PYGB gene. This alteration results from a G to A substitution at nucleotide position 2525, causing the arginine (R) at amino acid position 842 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.090
BayesDel_addAF	Benign	-0.070	T
BayesDel_noAF	Benign	-0.16
Cadd	Benign	19
Dann	Uncertain	0.99
DEOGEN2	Benign	0.25	T
Eigen	Benign	-0.70
Eigen_PC	Benign	-0.72
FATHMM_MKL	Benign	0.61	D
LIST_S2	Benign	0.68	T
M_CAP	Benign	0.073	D
MetaRNN	Benign	0.13	T
MetaSVM	Benign	-0.52	T
MutationAssessor	Uncertain	2.7	M
MutationTaster	Benign	1.0	D;N
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-0.43	N
REVEL	Benign	0.15
Sift	Uncertain	0.012	D
Sift4G	Uncertain	0.010	D
Polyphen		0.36	B
Vest4		0.14
MVP		0.84
MPC		0.24
ClinPred		0.23	T
GERP RS		-2.8
Varity_R		0.081
gMVP		0.42

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: rs200006792; hg19: chr20-25277151; COSMIC: COSV53815422; COSMIC: COSV53815422;