rs200412003

Variant names:

• chr17-80108382-G-A
• rs200412003
• NM_000152.5:c.1048G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP3 PM2_Supporting PS3_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000152.5(GAA):c.1048G>A variant in GAA is a missense variant predicted to cause substitution of valine by methionine at amino acid 350 (p.Val350Met). This variant has been detected in at least 12 individuals, and at least 11 patients with this variant had documented GAA deficiency with activity in the affected range in dried blood spot (Clinical Laboratory data, PMIDs: 25451853, 36310651, 36246652). However, in the absence of clinical symptoms to support that the variant causes Pompe disease, PP4 was not applied. Of those individuals, 1 was homozygous for the variant, and 11 were compound heterozygous for the variant and a pathogenic or likely pathogenic variant in GAA; 2 of those were confirmed in trans by parental testing, including c.-32-13T>G (9 patients, Clinical laboratory data, PMID:25451853, 1 patient confirmed in trans), c.2051C>T (p.Pro684Leu) (1 patient, PMID:36310651, phase unknown), c.1589del (p.Glu530GlyfsTer48) (1 patient, PMID:36246652, phase unknown), and c.2238G>C (p.Trp746Cys) (2 patients, one confirmed in trans and one with a pseudodeficiency allele, Clinical Laboratory data). Due to lack of clinical symptoms in these patients, PM3 is not met at the current time. When expressed in HEK293 cells, GAA enzyme activity was 1.5% of the positive control (Table 3). Western blot revealed faint precursor (110 k Da) and mature (76 kDa) protein bands with lower intensity compared to the positive control, indicating this variant may be impacting GAA protein stability and processing (PS3_Supporting). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00013 (17/1128822 alleles) in the European non-Finnish population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2_Supporting (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.878 which is above the threshold of 0.7, evidence that correlates with impact to GAA function (PP3). There is a ClinVar entry for this variant (Variation ID: 555998). In summary, while patients with this variant have been reported with deficiency GAA activity, and the variant has been found in compound heterozygosity with pathogenic and likely pathogenic variants in GAA, the Lysosomal Diseases VCEP concluded that there is insufficient phenotypic evidence to indicate that this variant cuases Pompe disease at this time. Therefore, this variant will be classified as a variant of uncertain significance until further evidence is available. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert Panel (Specifications Version 2.0): PS3_Supporting, PP3, PM2_Supporting.(Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on March 19, 2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815133/MONDO:0009290/010

• Frequency:
  • Genomes: 𝑓 0.000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000088 (0 hom.)
• Consequence: GAA NM_000152.5 missense
• Clinical Significance: Uncertain significance reviewed by expert panel P:4 U:9
• Conservation: PhyloP100: 9.38
• Publications: 9 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: Uncertain_significance. The variant received 3 ACMG points.

• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: 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.1048G>A	p.Val350Met	missense_variant	Exon 6 of 20	ENST00000302262.8	NP_000143.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8	c.1048G>A	p.Val350Met	missense_variant	Exon 6 of 20	1	NM_000152.5	ENSP00000305692.3

Frequencies

GnomAD3 genomes AF: 0.0000657 AC: 10 AN: 152244 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000941

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000103

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000956 AC: 24 AN: 251022 AF XY: 0.000103

Gnomad AFR exome AF: 0.0000618

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.000508

Gnomad NFE exome AF: 0.0000970

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000876 AC: 128 AN: 1461186 Hom.: 0 Cov.: 38 AF XY: 0.0000949 AC XY: 69 AN XY: 726902

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

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

South Asian (SAS) AF: 0.0000232 AC: 2 AN: 86258

European-Finnish (FIN) AF: 0.000550 AC: 29 AN: 52724

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000818 AC: 91 AN: 1112008

Other (OTH) AF: 0.0000662 AC: 4 AN: 60390

GnomAD4 genome AF: 0.0000657 AC: 10 AN: 152244 Hom.: 0 Cov.: 33 AF XY: 0.0000403 AC XY: 3 AN XY: 74372

African (AFR) AF: 0.00 AC: 0 AN: 41460

American (AMR) AF: 0.000131 AC: 2 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.0000941 AC: 1 AN: 10632

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

European-Non Finnish (NFE) AF: 0.000103 AC: 7 AN: 68046

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.000150 Hom.: 0

Bravo AF: 0.0000227

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000576 AC: 7

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:4 Uncertain:9

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:3 Uncertain:6

Sep 05, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 22, 2024

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 16, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jan 22, 2020

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: curation

The p.Val350Met variant in GAA has been reported in 2 individuals with glycogen storage disease II (PMID: 25786784, 25451853) and has been identified in 0.04% (11/25122) of European (Finnish) chromosomes, 0.013% (17/128822) of European (non-Finnish) chromosomes, and 0.004% (1/24900) of African chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs200412003). 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 has also been reported in ClinVar as a VUS by Counsyl and Invitae (VariationID: 555998). Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. The phenotype of individuals heterozygous for this variant is highly specific for glycogen storage disease II based on GAA enzyme activity in muscle and lymphocytes being <10% of wild type, consistent with disease (PMID: 25786784, 25451853). Additionally, the presence of this variant in combination with reported pathogenic variant c.-32-13T>G and in individuals with glycogen storage disease II slightly increases the likelihood that the p.Val350Met variant is pathogenic. In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PM3_supporting, PM2, PP3, PP4 (Richards 2015). -

Sep 14, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 350 of the GAA protein (p.Val350Met). This variant is present in population databases (rs200412003, gnomAD 0.05%). This missense change has been observed in individual(s) with Pompe disease (PMID: 23430949, 25451853, 36246652). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 555998). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt GAA protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects GAA function (PMID: 36246652). For these reasons, this variant has been classified as Pathogenic. -

May 30, 2024

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GAA c.1048G>A (p.Val350Met) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 9.6e-05 in 251022 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in GAA causing Late Onset Pompe Disease (9.6e-05 vs 0.0042), allowing no conclusion about variant significance. c.1048G>A has been reported in the literature in infants with indications of Late Onset Pompe Disease via newborn screening who were compound heterozygous with pathogenic variants (e.g. Lee_2022, Goomber_2022). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function, finding that the variant results in 1.5% of wild type GAA enzyme activity (Goomber_2022). The following publications have been ascertained in the context of this evaluation (PMID: 23430949, 24627108, 30155607, 33073007, 25786784, 25451853, 34995642, 36246652, 36310651). ClinVar contains an entry for this variant (Variation ID: 555998). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Nov 08, 2021

Myriad Genetics, Inc.

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NM_000152.3(GAA):c.1048G>A(V350M) is a missense variant classified as a variant of uncertain significance in the context of Pompe disease. V350M has been observed in cases with relevant disease (PMID 25451853, 23430949). Functional assessments of this variant are not available in the literature. V350M has been observed in population frequency databases (gnomAD: FIN 0.05%). In summary, there is insufficient evidence to classify NM_000152.3(GAA):c.1048G>A(V350M) as pathogenic or benign. Please note: this variant was assessed in the context of healthy population screening. -

Mar 19, 2024

ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000152.5(GAA):c.1048G>A variant in GAA is a missense variant predicted to cause substitution of valine by methionine at amino acid 350 (p.Val350Met). This variant has been detected in at least 12 individuals, and at least 11 patients with this variant had documented GAA deficiency with activity in the affected range in dried blood spot (Clinical Laboratory data, PMIDs: 25451853, 36310651, 36246652). However, in the absence of clinical symptoms to support that the variant causes Pompe disease, PP4 was not applied. Of those individuals, 1 was homozygous for the variant, and 11 were compound heterozygous for the variant and a pathogenic or likely pathogenic variant in GAA; 2 of those were confirmed in trans by parental testing, including c.-32-13T>G (9 patients, Clinical laboratory data, PMID:25451853, 1 patient confirmed in trans), c.2051C>T (p.Pro684Leu) (1 patient, PMID:36310651, phase unknown), c.1589del (p.Glu530GlyfsTer48) (1 patient, PMID: 36246652, phase unknown), and c.2238G>C (p.Trp746Cys) (2 patients, one confirmed in trans and one with a pseudodeficiency allele, Clinical Laboratory data). Due to lack of clinical symptoms in these patients, PM3 is not met at the current time. When expressed in HEK293 cells, GAA enzyme activity was 1.5% of the positive control (Table 3). Western blot revealed faint precursor (110 k Da) and mature (76 kDa) protein bands with lower intensity compared to the positive control, indicating this variant may be impacting GAA protein stability and processing (PS3_Supporting). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00013 (17/1128822 alleles) in the European non-Finnish population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2_Supporting (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.878 which is above the threshold of 0.7, evidence that correlates with impact to GAA function (PP3). There is a ClinVar entry for this variant (Variation ID: 555998). In summary, while patients with this variant have been reported with deficiency GAA activity, and the variant has been found in compound heterozygosity with pathogenic and likely pathogenic variants in GAA, the Lysosomal Diseases VCEP concluded that there is insufficient phenotypic evidence to indicate that this variant cuases Pompe disease at this time. Therefore, this variant will be classified as a variant of uncertain significance until further evidence is available. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert Panel (Specifications Version 2.0): PS3_Supporting, PP3, PM2_Supporting. (Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on March 19, 2024). -

not provided Pathogenic:1 Uncertain:3

May 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

GAA: PM2, PM3, PS3:Supporting -

Feb 08, 2024

Mayo Clinic Laboratories, Mayo Clinic

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PP3, PP4_moderate, PM2, PM3, PS3_moderate -

Nov 14, 2023

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 04, 2020

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported previously as heterozygous along with another variant in the GAA gene in an asymptomatic adult with decreased alpha glucosidase activity in multiple tissues (Echaniz-Laguna et al., 2015); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23430949, 25786784, 24627108, 25451853) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.49
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	31
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.95	D;D
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.6	H;H
PhyloP100		9.4
PrimateAI	Uncertain	0.63	T
PROVEAN	Uncertain	-3.0	D;D
REVEL	Pathogenic	0.88
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.81
MVP		0.95
MPC		0.54
ClinPred		0.97	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.93
gMVP		0.87
Mutation Taster		=56/44	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs200412003; hg19: chr17-78082181; COSMIC: COSV107393407; COSMIC: COSV107393407;