chr12-21559170-C-T

Variant names:

• chr12-21559170-C-T
• rs766733439
• NM_021957.4:c.1230-1G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_021957.4(GYS2):​c.1230-1G>A variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000818 in 1,589,064 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 Likely pathogenic (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000083 (0 hom.)
• Consequence: GYS2 NM_021957.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.68
• Publications: 0 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 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5.5, offset of 2, new splice context is: aacattttttccctgcaaAGgag. 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
• PP5: Variant 12-21559170-C-T is Pathogenic according to our data. Variant chr12-21559170-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 402231.Status of the report is criteria_provided_single_submitter, 1 stars.

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.1230-1G>A		splice_acceptor 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.1230-1G>A		splice_acceptor intron	N/A	ENSP00000261195.2	P54840
	ENSG00000285854	ENST00000647960.1		n.*1232-1G>A		splice_acceptor intron	N/A	ENSP00000497202.1	A0A3B3IS95
	GYS2	ENST00000863011.1		c.1344-1G>A		splice_acceptor intron	N/A	ENSP00000533070.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151932 Hom.: 0 Cov.: 32

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000200 AC: 5 AN: 250336 AF XY: 0.0000295

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: 0.0000441

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000835 AC: 12 AN: 1437132 Hom.: 0 Cov.: 25 AF XY: 0.0000126 AC XY: 9 AN XY: 716462

African (AFR) AF: 0.00 AC: 0 AN: 32916

American (AMR) AF: 0.00 AC: 0 AN: 44590

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25920

East Asian (EAS) AF: 0.00 AC: 0 AN: 39340

South Asian (SAS) AF: 0.00 AC: 0 AN: 85386

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53208

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 0.0000110 AC: 12 AN: 1090584

Other (OTH) AF: 0.00 AC: 0 AN: 59498

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151932 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74202

African (AFR) AF: 0.00 AC: 0 AN: 41382

American (AMR) AF: 0.00 AC: 0 AN: 15258

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10506

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

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67974

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

Alfa AF: 0.0000675 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.0000165 AC: 2

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Glycogen storage disorder due to hepatic glycogen synthase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	35
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.7
GERP RS		4.8
Mutation Taster		=0/100	disease causing (ClinVar)

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		0.87		Position offset: -3
DS_AL_spliceai		0.99		Position offset: -1

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

Other links and lift over

dbSNP: rs766733439; hg19: chr12-21712104;