rs200412003

Positions:

chr17-80108382-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PS3_SupportingPP3PM2_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

Scores

Clinical Significance

Uncertain significance reviewed by expert panel P:4U:9

Conservation

PhyloP100: 9.38

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 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/exons	MANE	Protein	UniProt
GAA	NM_000152.5 link	c.1048G>A	p.Val350Met	missense_variant	6/20	ENST00000302262.8	NP_000143.2	P10253

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8 link	c.1048G>A	p.Val350Met	missense_variant	6/20	1	NM_000152.5	ENSP00000305692.3		P10253

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152244

Hom.:

Cov.:

show subpopulations

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

GnomAD3 exomes

AF:

0.0000956

AC:

AN:

251022

Hom.:

AF XY:

0.000103

AC XY:

AN XY:

135858

show subpopulations

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 SAS 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.:

Cov.:

AF XY:

0.0000949

AC XY:

AN XY:

726902

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.000550

Gnomad4 NFE exome

AF:

0.0000818

Gnomad4 OTH exome

AF:

0.0000662

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152244

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74372

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.0000941

Gnomad4 NFE

AF:

0.000103

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000150

Hom.:

Bravo

AF:

0.0000227

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000576

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:4Uncertain:9

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Glycogen storage disease, type II

Pathogenic:3Uncertain:6

Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Sep 14, 2021	- -
Uncertain significance, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Mar 19, 2024	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). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 22, 2024	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 30, 2024	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. -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Uncertain significance, criteria provided, single submitter	curation	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Jan 22, 2020	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). -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 31, 2024	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). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Nov 08, 2021	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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 05, 2021	- -

not provided

Pathogenic:1Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Nov 14, 2023	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Feb 08, 2024	PP3, PP4_moderate, PM2, PM3, PS3_moderate -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	May 01, 2023	GAA: PM2, PM3, PS3:Supporting -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Nov 04, 2020	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

BayesDel_noAF

Pathogenic

0.30

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.95

D;D

Eigen

Pathogenic

0.98

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

.;D

M_CAP

Pathogenic

0.84

MetaRNN

Pathogenic

0.94

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.6

H;H

PrimateAI

Uncertain

0.63

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

GERP RS

5.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.93

gMVP

0.87

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over