rs886043343

Variant names:

• chr17-80118209-CCA-C
• rs886043343
• NM_000152.5:c.2501_2502delCA

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PP4 PM3_Supporting PM2 PVS1

This summary comes from the ClinGen Evidence Repository: This variant, c.2501_2502delCA (p.Thr834Argfs) is predicted to result in a frameshift causing a premature termination codon, nonsense medicated decay, and lack of GAA gene product, meeting PVS1. The variant has a highest population minor allele frequency of 0.00005794 in the Latino population, meeting PM2. This variant was found in compound heterozygosity with a known pathogenic variant, c.-32-13T>G, in three patients, who all meet the ClinGen LSD VCEP's PP4 criterion (PMID 22958975). The phase not confirmed in any of these patients. Additional patients with this variant have been reported but were not included because the residual GAA activity was not provided, and therefore PP4 cannot be assessed (PMIDs 19588081, 29122469), or the in trans data had been counted towards another variant and therefore were not included here to avoid circular logic (c.1933G>A (p.Asp645Asn), (PMID 23601496). The data meet PP4 and PM3_Supporting. There is a ClinVar entry for this variant (Variant ID: 286229; 2 star review status) with three submitters classifying the variant as pathogenic and one as likely pathogenic. In summary, this variant meets the criteria to be classified as pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP: PVS1, PM2, PM3_Supporting, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA10605404/MONDO:0009290/010

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GAA NM_000152.5 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:11
• Conservation: PhyloP100: 1.17
• Publications: 7 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: Pathogenic. The variant received 12 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.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GAA	NM_000152.5	c.2501_2502delCA	p.Thr834ArgfsTer49	frameshift_variant	Exon 18 of 20	ENST00000302262.8	NP_000143.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8	c.2501_2502delCA	p.Thr834ArgfsTer49	frameshift_variant	Exon 18 of 20	1	NM_000152.5	ENSP00000305692.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000799 AC: 2 AN: 250190 AF XY: 0.00000738

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000579

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1460844 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 726688

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.0000448 AC: 2 AN: 44674

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26114

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86192

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52724

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111848

Other (OTH) AF: 0.00 AC: 0 AN: 60366

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:11

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:8

Nov 30, 2018

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GAA c.2501_2502delCA (p.Thr834ArgfsX49) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (eg. c.2544delC, p.Lys849fsX38 and c.2560C>T, p.Arg854X). The variant allele was found at a frequency of 8.1e-06 in 245500 control chromosomes (gnomAD). The variant, c.2501_2502delCA, has been reported in the literature in individuals affected with Glycogen Storage Disease, Type 2 (Pompe Disease)(Kroos_2008, Palermo_2012, Musumeci_2012). These data indicate that the variant is likely to be associated with disease. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Jan 20, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Thr834Argfs*49) in the GAA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GAA are known to be pathogenic (PMID: 18425781, 22252923). This variant is present in population databases (no rsID available, gnomAD 0.006%). This premature translational stop signal has been observed in individuals with Pompe disease (PMID: 19588081, 22958975, 29122469, 30564623). ClinVar contains an entry for this variant (Variation ID: 286229). For these reasons, this variant has been classified as Pathogenic. -

-

Tehran Medical Genetics Laboratory

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 18, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 05, 2020

ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

This variant, c.2501_2502delCA (p.Thr834Argfs) is predicted to result in a frameshift causing a premature termination codon, nonsense medicated decay, and lack of GAA gene product, meeting PVS1. The variant has a highest population minor allele frequency of 0.00005794 in the Latino population, meeting PM2. This variant was found in compound heterozygosity with a known pathogenic variant, c.-32-13T>G, in three patients, who all meet the ClinGen LSD VCEP's PP4 criterion (PMID 22958975). The phase not confirmed in any of these patients. Additional patients with this variant have been reported but were not included because the residual GAA activity was not provided, and therefore PP4 cannot be assessed (PMIDs 19588081, 29122469), or the in trans data had been counted towards another variant and therefore were not included here to avoid circular logic (c.1933G>A (p.Asp645Asn), (PMID 23601496). The data meet PP4 and PM3_Supporting. There is a ClinVar entry for this variant (Variant ID: 286229; 2 star review status) with three submitters classifying the variant as pathogenic and one as likely pathogenic. In summary, this variant meets the criteria to be classified as pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP: PVS1, PM2, PM3_Supporting, PP4. -

Jan 22, 2020

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

The p.Thr834ArgfsTer49 variant in GAA has been reported in 8 individuals with Glycogen Storage Disease II (PMID: 22958975, 23601496, 29122469, 19588081), and has also been reported pathogenic by EGL and likely pathogenic by Tehran Medical Genetics Laboratory and Integrated Genetics in ClinVar (Variation ID: 286229). This variant has been identified in 0.0058% (2/34516) of Latino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs886043343). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This variant is predicted to cause a frameshift, which alters the protein's amino acid sequence beginning at position 834 and leads to a premature termination codon 49 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the GAA gene is an established disease mechanism in autosomal recessive Glycogen Storage Disease II. The presence of this variant in combination with a reported pathogenic variant and in individuals with Glycogen Storage Disease II increases the likelihood that the p.Thr834ArgfsTer49 variant is pathogenic (PMID: 19588081). The phenotype of individuals heterozygous for this variant is highly specific for Glycogen Storage Disease II based on reduced GAA activity in a dried blood spot or muscle tissue, consistent with disease (PMID: 22958975, 23601496). In summary, this variant meets criteria to be classified as pathogenic for Glycogen Storage Disease II in an autosomal recessive manner based on the predicted impact of the variant and multiple occurrences with pathogenic GAA variants in individuals with Glycogen Storage Disease II. ACMG/AMP Criteria applied: PVS1, PM2, PM3_Supporting, PP4 (Richards 2015). -

Nov 17, 2016

Counsyl

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not provided Pathogenic:3

Nov 17, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed with a second GAA variant in unrelated patients with GSDII in published literature, but it is not known whether the variants occurred on the same (in cis) or on different (in trans) chromosomes in all cases (PMID: 23601496, 31086307, 30564623); Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at a significant frequency in large population cohorts (gnomAD); Reported in ClinVar but additional evidence is not available (ClinVar Variant ID# 286229; ClinVar); This variant is associated with the following publications: (PMID: 31254424, 19588081, 31589614, 18425781, 23601496, 31086307, 30564623) -

Feb 23, 2016

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 16, 2021

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.2
Mutation Taster		=3/197	disease causing (ClinVar)

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: rs886043343; hg19: chr17-78092008;