rs397515342

Variant names:

• chr3-81642991-C-T
• rs397515342
• NM_000158.4:c.783-1G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1_Moderate PS3 PM2 PP5_Moderate

The NM_000158.4(GBE1):​c.783-1G>A variant causes a splice acceptor, intron 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★). ClinVar reports functional evidence for this variant: "SCV004569657: Experimental studies have shown that disruption of this splice site affects GBE1 function (PMID:8613547). Studies have shown that disruption of this splice site results in skipping of exon 7, but is expected to preserve the integrity of the reading-frame (PMID:8613547).".

• Frequency: Genomes: not found (cov: 32)
• Consequence: GBE1 NM_000158.4 splice_acceptor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.45
• Publications: 1 publications found

Genes affected

GBE1 (HGNC:4180): (1,4-alpha-glucan branching enzyme 1) The protein encoded by this gene is a glycogen branching enzyme that catalyzes the transfer of alpha-1,4-linked glucosyl units from the outer end of a glycogen chain to an alpha-1,6 position on the same or a neighboring glycogen chain. Branching of the chains is essential to increase the solubility of the glycogen molecule and, consequently, in reducing the osmotic pressure within cells. Highest level of this enzyme are found in liver and muscle. Mutations in this gene are associated with glycogen storage disease IV (also known as Andersen's disease). [provided by RefSeq, Jul 2008]

GBE1 Gene-Disease associations (from GenCC):

• glycogen storage disease due to glycogen branching enzyme deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Laboratory for Molecular Medicine, G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen
• adult polyglucosan body disease

  Inheritance: AR Classification: MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet

ACMG classification

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

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.099573255 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV004569657: Experimental studies have shown that disruption of this splice site affects GBE1 function (PMID: 8613547). Studies have shown that disruption of this splice site results in skipping of exon 7, but is expected to preserve the integrity of the reading-frame (PMID: 8613547).
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-81642991-C-T is Pathogenic according to our data. Variant chr3-81642991-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2776.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000158.4. 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
	GBE1	NM_000158.4	MANE Select	c.783-1G>A		splice_acceptor intron	N/A	NP_000149.4	Q04446

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GBE1	ENST00000429644.7	TSL:1 MANE Select	c.783-1G>A		splice_acceptor intron	N/A	ENSP00000410833.2	Q04446
	GBE1	ENST00000895874.1		c.783-1G>A		splice_acceptor intron	N/A	ENSP00000565933.1
	GBE1	ENST00000942742.1		c.777-1G>A		splice_acceptor intron	N/A	ENSP00000612801.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Glycogen storage disease due to glycogen branching enzyme deficiency, congenital neuromuscular form (1)
1	-	-	Glycogen storage disease, type IV;C1856301:Glycogen storage disease IV, classic hepatic (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		7.5
GERP RS		5.0
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.75		Position offset: -21
DS_AL_spliceai		1.0		Position offset: -1

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

Other links and lift over

dbSNP: rs397515342; hg19: chr3-81692142;