12-21558286-G-T

Variant names:

• chr12-21558286-G-T
• rs121918425
• NM_021957.4:c.1336C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_021957.4(GYS2):​c.1336C>A​(p.His446Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. H446D) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GYS2 NM_021957.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.90
• Publications: 4 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: STRONG, SUPPORTIVE Submitted by: Orphanet, PanelApp Australia, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)

ENSG00000285854 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.939

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GYS2	NM_021957.4	c.1336C>A	p.His446Asn	missense_variant	Exon 11 of 16	ENST00000261195.3	NP_068776.2
GYS2	XM_024448960.2	c.1336C>A	p.His446Asn	missense_variant	Exon 11 of 17		XP_024304728.1
GYS2	XM_006719063.4	c.1105C>A	p.His369Asn	missense_variant	Exon 10 of 15		XP_006719126.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GYS2	ENST00000261195.3	c.1336C>A	p.His446Asn	missense_variant	Exon 11 of 16	1	NM_021957.4	ENSP00000261195.2
ENSG00000285854	ENST00000647960.1	n.*1338C>A		non_coding_transcript_exon_variant	Exon 18 of 23			ENSP00000497202.1
ENSG00000285854	ENST00000647960.1	n.*1338C>A		3_prime_UTR_variant	Exon 18 of 23			ENSP00000497202.1
ENSG00000285854	ENST00000648372.1	n.1263C>A		non_coding_transcript_exon_variant	Exon 11 of 11

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.040
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.78	D
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Uncertain	0.10	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	0.53	D
MutationAssessor	Pathogenic	3.5	M
PhyloP100		9.9
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-6.9	D
REVEL	Pathogenic	0.72
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.77		Gain of catalytic residue at P441 (P = 0.001);
MVP		0.93
MPC		0.59
ClinPred		1.0	D
GERP RS		4.5
Varity_R		0.90
gMVP		0.91
Mutation Taster		=43/57	disease causing

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

Other links and lift over

dbSNP: rs121918425; hg19: chr12-21711220; COSMIC: COSV53927357;