chr17-80118746-C-T

Variant names:

• chr17-80118746-C-T
• rs1555603264
• NM_000152.5:c.2740C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM2_Supporting PVS1

This summary comes from the ClinGen Evidence Repository: The NM_000152.5:c.2740C>T (p.Gln914Ter) variant in GAA is a nonsense variant predicted to cause a premature stop codon (PTC) in biologically-relevant-exon 19/20, in a gene in which loss-of-function is an established disease mechanism. While the PTC occurs in the penultimate exon of GAA, it is still predicted to lead to nonsense mediated decay (PVS1). The variant is absent in gnomAD v2.1.1. (PM2_Supporting). To our knowledge, this variant has not been reported in the literature in individuals with Pompe disease, and results of experimental studies are not available. There is a ClinVar entry for this variant (Variation ID: 456415). The classification of this variant has been upgraded from Variant of Uncertain Significance to Likely Pathogenic based on the recommendations of the ClinGen Sequence Variant Interpretation Working Group, that a variant meeting PVS1 and PM2_Supporting is classified as Likely Pathogenic (https://clinicalgenome.org/site/assets/files/5182/pm2_-_svi_recommendation_-_approved_sept2020.pdf ). In summary, this variant meets the criteria to be classified as Likely Pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria met, based on the specifications of the ClinGen Lysosomal Diseases VCEP (Specifications Version 2.0): PVS1, PM2_Supporting.(Classification approved by the ClinGen Lysosomal Diseases VCEP, March 10, 2023). LINK:https://erepo.genome.network/evrepo/ui/classification/CA401327117/MONDO:0009290/010

• Frequency: Genomes: not found (cov: 32)
• Consequence: GAA NM_000152.5 stop_gained
• Clinical Significance: Likely pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: -0.229
• Publications: 0 publications found

Genes affected

GAA (HGNC:4065): (alpha glucosidase) This gene encodes lysosomal alpha-glucosidase, which is essential for the degradation of glycogen to glucose in lysosomes. The encoded preproprotein is proteolytically processed to generate multiple intermediate forms and the mature form of the enzyme. Defects in this gene are the cause of glycogen storage disease II, also known as Pompe's disease, which is an autosomal recessive disorder with a broad clinical spectrum. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016]

GAA Gene-Disease associations (from GenCC):

• glycogen storage disease II

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), PanelApp Australia, ClinGen, G2P
• glycogen storage disease due to acid maltase deficiency, infantile onset

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• glycogen storage disease due to acid maltase deficiency, late-onset

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000152.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GAA	NM_000152.5	MANE Select	c.2740C>T	p.Gln914*	stop_gained	Exon 19 of 20	NP_000143.2
	GAA	NM_001079803.3		c.2740C>T	p.Gln914*	stop_gained	Exon 20 of 21	NP_001073271.1
	GAA	NM_001079804.3		c.2740C>T	p.Gln914*	stop_gained	Exon 19 of 20	NP_001073272.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GAA	ENST00000302262.8	TSL:1 MANE Select	c.2740C>T	p.Gln914*	stop_gained	Exon 19 of 20	ENSP00000305692.3
	GAA	ENST00000390015.7	TSL:1	c.2740C>T	p.Gln914*	stop_gained	Exon 20 of 21	ENSP00000374665.3
	GAA	ENST00000570803.6	TSL:5	c.2740C>T	p.Gln914*	stop_gained	Exon 19 of 20	ENSP00000460543.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
3	-	-	Glycogen storage disease, type II (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	34
DANN	Uncertain	0.98
Eigen	Benign	-0.0038
Eigen_PC	Benign	-0.34
FATHMM_MKL	Benign	0.032	N
PhyloP100		-0.23
Vest4		0.81
GERP RS		-2.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs1555603264; hg19: chr17-78092545;