rs552929702

Positions:

chr17-80107809-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PM2_SupportingBS3_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000152.5:c.868A>G variant in GAA is predicted to result in the substitution of asparagine by aspartate at amino acid 290 (p.Asn290Asp). It has been identified in six individuals by newborn screening, none with clinical features consistent with Pompe disease (PMID:32064362, 37414610; Essawi et al. 2021, Egypt J Med Hum Genet 22:87). Four of these individuals are homozygous for the variant and have African ancestry (PMID:37414610), and two patients are compound heterozygous for the variant and a variant that has been classified as pathogenic by the ClinGen Lysosomal Diseases VCEP, either c.2105G>A (p.Arg702His), phase unconfirmed, (ClinVar Variation ID: 426278, SCV004809068.1) (PMID:32064362) or c.2238G>C (p.Trp746Cys) (ClinVar Variation ID: 265160, SCV002032122.1). In the latter, patient, the variants were confirmed to be in trans, and the father, who was described as "completely normal" but with reduced GAA activity, is homozygous for c.868A>G (p.Asn290Asp). Additional cases have been reported (PMID:22644586, 33073007) but the second variant and clinical details were not provided. Due to the lack of evidence for clinical symptoms in the patients with this variant, PP4 and PM3 were not applied. The highest population minor allele frequency in gnomAD v2.1.1. is 0.00004 (1/24356, no homozygotes) in the African population, which is lower than the ClinGen Lysosomal Diseases VCEP's threshold (<0.001) for PM2_Supporting, meeting this criterion (PM2_Supporting). When expressed in COS cells, this variant was classified as Class E ("presumably nonpathogenic") by Kroos et al, 2012 (PMID:22644586). This includes 71% GAA activity in cells and 38% in medium, with synthesis and processing on Western blot (BS3_Supporting). The computational predictor REVEL gives a score of 0.561 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function. There is a ClinVar entry for this variant (Variation ID: 498117). In summary, this variant meets the criteria to be classified as a variant of uncertain significance for Pompe disease. The classification was first approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on October 21, 2022. Since then, the data for this variant have been re-evaluated and new data have been included but the classification remains the same. The classification of variant of uncertain significance was reapproved on April 16, 2024. GAA-specific ACMG/AMP criteria met, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert Panel (Specifications Version 2.0): PM2_Supporting, BS3_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815078/MONDO:0009290/010

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000022 ( 2 hom. )

Consequence

GAA
NM_000152.5 missense

Scores

Clinical Significance

Uncertain significance reviewed by expert panel P:1U:8

Conservation

PhyloP100: 6.09

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 0 ACMG points.

PM2

For more information check the summary or visit ClinGen Evidence Repository.

BS3

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 linkuse as main transcript	c.868A>G	p.Asn290Asp	missense_variant	5/20	ENST00000302262.8	NP_000143.2	P10253

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8 linkuse as main transcript	c.868A>G	p.Asn290Asp	missense_variant	5/20	1	NM_000152.5	ENSP00000305692.3		P10253

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152122

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000966

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000408

AC:

AN:

245126

Hom.:

AF XY:

0.00

AC XY:

AN XY:

133458

show subpopulations

Gnomad AFR exome

AF:

0.0000638

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:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000219

AC:

AN:

1459490

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

726058

show subpopulations

Gnomad4 AFR exome

AF:

0.000658

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000270

Gnomad4 OTH exome

AF:

0.0000830

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74442

show subpopulations

Gnomad4 AFR

AF:

0.000120

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000113

ExAC

AF:

0.00000825

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:8

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Glycogen storage disease, type II

Pathogenic:1Uncertain:3

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Feb 13, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 05, 2021	- -
Uncertain significance, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Apr 16, 2024	The NM_000152.5:c.868A>G variant in GAA is predicted to result in the substitution of asparagine by aspartate at amino acid 290 (p.Asn290Asp). It has been identified in six individuals by newborn screening, none with clinical features consistent with Pompe disease (PMID: 32064362, 37414610; Essawi et al. 2021, Egypt J Med Hum Genet 22:87). Four of these individuals are homozygous for the variant and have African ancestry (PMID: 37414610), and two patients are compound heterozygous for the variant and a variant that has been classified as pathogenic by the ClinGen Lysosomal Diseases VCEP, either c.2105G>A (p.Arg702His), phase unconfirmed, (ClinVar Variation ID: 426278, SCV004809068.1) (PMID: 32064362) or c.2238G>C (p.Trp746Cys) (ClinVar Variation ID: 265160, SCV002032122.1). In the latter, patient, the variants were confirmed to be in trans, and the father, who was described as "completely normal" but with reduced GAA activity, is homozygous for c.868A>G (p.Asn290Asp). Additional cases have been reported (PMID: 22644586, 33073007) but the second variant and clinical details were not provided. Due to the lack of evidence for clinical symptoms in the patients with this variant, PP4 and PM3 were not applied. The highest population minor allele frequency in gnomAD v2.1.1. is 0.00004 (1/24356, no homozygotes) in the African population, which is lower than the ClinGen Lysosomal Diseases VCEP's threshold (<0.001) for PM2_Supporting, meeting this criterion (PM2_Supporting). When expressed in COS cells, this variant was classified as Class E ("presumably nonpathogenic") by Kroos et al, 2012 (PMID:22644586). This includes 71% GAA activity in cells and 38% in medium, with synthesis and processing on Western blot (BS3_Supporting). The computational predictor REVEL gives a score of 0.561 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function. There is a ClinVar entry for this variant (Variation ID: 498117). In summary, this variant meets the criteria to be classified as a variant of uncertain significance for Pompe disease. The classification was first approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on October 21, 2022. Since then, the data for this variant have been re-evaluated and new data have been included but the classification remains the same. The classification of variant of uncertain significance was reapproved on April 16, 2024. GAA-specific ACMG/AMP criteria met, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert Panel (Specifications Version 2.0): PM2_Supporting, BS3_Supporting. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 29, 2024	This sequence change replaces asparagine, which is neutral and polar, with aspartic acid, which is acidic and polar, at codon 290 of the GAA protein (p.Asn290Asp). This variant is present in population databases (rs552929702, gnomAD 0.004%), including at least one homozygous and/or hemizygous individual. To date, this missense change has only been observed in individual(s) with abnormal newborn screening for Pompe disease (PMID: 32064362; Invitae). 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: 498117). 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%. This variant disrupts the p.Asn290 amino acid residue in GAA. Other variant(s) that disrupt this residue have been observed in individuals with GAA-related conditions (PMID: 22081099; Invitae), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

not provided

Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Oct 17, 2023	Identified with a second variant in the GAA gene in an asymptomatic infant with reduced alpha-glucosidase activity on newborn screening; the variant was apparently homozygous in the father who was clinically asymptomatic, but had significantly reduced alpha-glucosidase activity (Mona Essawi et al., 2021); Not observed at significant frequency in large population cohorts (gnomAD); 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: 22253258, 19343043, 22644586, 32064362, 37414610, Essawi2021) -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jan 30, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Aug 30, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Oct 11, 2022	PM2 -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jun 05, 2021

Variant summary: GAA c.868A>G (p.Asn290Asp) results in a conservative amino acid change located in the Glycoside hydrosylase family 31, N-terminal domain (IPR025887) of 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 4.1e-06 in 245126 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. Although this variant is listed as "non-pathogenic" in the Pompe disease database without any supporting clinical evidence, to our knowledge, no occurrence of c.868A>G in individuals affected with Glycogen Storage Disease, Type 2 (Pompe Disease) and no experimental evidence demonstrating its impact on protein function have been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.83

BayesDel_addAF

Uncertain

0.13

BayesDel_noAF

Uncertain

-0.050

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.92

D;D

Eigen

Pathogenic

0.77

Eigen_PC

Pathogenic

0.69

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

.;D

M_CAP

Pathogenic

0.36

MetaRNN

Pathogenic

0.91

D;D

MetaSVM

Uncertain

0.78

MutationAssessor

Pathogenic

2.9

M;M

PrimateAI

Uncertain

0.63

PROVEAN

Pathogenic

-4.5

D;D

REVEL

Uncertain

0.56

Sift

Uncertain

0.0090

D;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

1.0

D;D

Vest4

0.94

MutPred

0.39

Gain of phosphorylation at Y292 (P = 0.0793);Gain of phosphorylation at Y292 (P = 0.0793);

MVP

1.0

MPC

0.58

ClinPred

0.99

GERP RS

5.3

Varity_R

0.90

gMVP

0.95

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

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