NM_021957.4:c.941+1G>A

Variant names:

• chr12-21563227-C-T
• rs587776831
• NM_021957.4:c.941+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_021957.4(GYS2):​c.941+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,116 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GYS2 NM_021957.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.88
• Publications: 1 publications found

Genes affected

GYS2 (HGNC:4707): (glycogen synthase 2) The protein encoded by this gene, liver glycogen synthase, catalyzes the rate-limiting step in the synthesis of glycogen - the transfer of a glucose molecule from UDP-glucose to a terminal branch of the glycogen molecule. Mutations in this gene cause glycogen storage disease type 0 (GSD-0) - a rare type of early childhood fasting hypoglycemia with decreased liver glycogen content. [provided by RefSeq, Dec 2009]

GYS2 Gene-Disease associations (from GenCC):

• glycogen storage disorder due to hepatic glycogen synthase deficiency

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

ENSG00000285854 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.3, offset of -13, new splice context is: gagGTcatt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_021957.4. 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
	GYS2	NM_021957.4	MANE Select	c.941+1G>A		splice_donor intron	N/A	NP_068776.2	P54840

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GYS2	ENST00000261195.3	TSL:1 MANE Select	c.941+1G>A		splice_donor intron	N/A	ENSP00000261195.2	P54840
	ENSG00000285854	ENST00000647960.1		n.*943+1G>A		splice_donor intron	N/A	ENSP00000497202.1	A0A3B3IS95
	GYS2	ENST00000863011.1		c.1055+1G>A		splice_donor intron	N/A	ENSP00000533070.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152116 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1388616 Hom.: 0 Cov.: 25 AF XY: 0.00 AC XY: 0 AN XY: 695198

African (AFR) AF: 0.00 AC: 0 AN: 31984

American (AMR) AF: 0.00 AC: 0 AN: 44640

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25674

East Asian (EAS) AF: 0.00 AC: 0 AN: 39282

South Asian (SAS) AF: 0.00 AC: 0 AN: 84772

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53366

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5644

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1045326

Other (OTH) AF: 0.00 AC: 0 AN: 57928

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152116 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74306

African (AFR) AF: 0.0000241 AC: 1 AN: 41414

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3466

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10600

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68016

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Uncertain	0.76	D
PhyloP100		7.9
GERP RS		5.1
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.31		Position offset: 14
DS_DL_spliceai		0.98		Position offset: 1

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

Other links and lift over

dbSNP: rs587776831; hg19: chr12-21716161;