Genetic Variant GAA:p.Pro253Arg (chr17-80107622-C-G) – ACMG Classification: Likely_pathogenic (7 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1PM2PP2PP3_Moderate

The NM_000152.5(GAA):c.758C>G(p.Pro253Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000161 in 1,613,112 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P253S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 34)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

GAA
NM_000152.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 7.79

Publications

2 publications found

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 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

GAA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 13 uncertain in NM_000152.5

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 201 curated pathogenic missense variants (we use a threshold of 10). The gene has 50 curated benign missense variants. Gene score misZ: -0.63308 (below the threshold of 3.09). Trascript score misZ: -0.32889 (below the threshold of 3.09). GenCC associations: The gene is linked to glycogen storage disease due to acid maltase deficiency, infantile onset, glycogen storage disease II, glycogen storage disease due to acid maltase deficiency, late-onset.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.894

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

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
GAA	NM_000152.5	MANE Select	c.758C>G	p.Pro253Arg	missense	Exon 4 of 20	NP_000143.2
GAA	NM_001079803.3		c.758C>G	p.Pro253Arg	missense	Exon 5 of 21	NP_001073271.1
GAA	NM_001079804.3		c.758C>G	p.Pro253Arg	missense	Exon 4 of 20	NP_001073272.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
GAA	ENST00000302262.8	TSL:1 MANE Select	c.758C>G	p.Pro253Arg	missense	Exon 4 of 20	ENSP00000305692.3
GAA	ENST00000390015.7	TSL:1	c.758C>G	p.Pro253Arg	missense	Exon 5 of 21	ENSP00000374665.3
GAA	ENST00000570803.6	TSL:5	c.758C>G	p.Pro253Arg	missense	Exon 4 of 20	ENSP00000460543.2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152196

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251144

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000171

AC:

AN:

1460916

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

726780

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000225

AC:

AN:

1111894

Other (OTH)

AF:

0.00

AC:

AN:

60370

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152196

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74338

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.675

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000508

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Glycogen storage disease, type II

Uncertain:1

Jun 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 253 of the GAA protein (p.Pro253Arg). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with GAA-related conditions. ClinVar contains an entry for this variant (Variation ID: 456437). 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%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

not provided

Uncertain:1

Nov 14, 2023

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiovascular phenotype

Uncertain:1

Apr 20, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.758C>G (p.P253R) alteration is located in exon 4 (coding exon 3) of the GAA gene. This alteration results from a C to G substitution at nucleotide position 758, causing the proline (P) at amino acid position 253 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.28

BayesDel_addAF

Pathogenic

0.18

BayesDel_noAF

Uncertain

0.030

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.85

Eigen

Pathogenic

0.89

Eigen_PC

Pathogenic

0.75

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.90

M_CAP

Pathogenic

0.32

MetaRNN

Pathogenic

0.89

MetaSVM

Pathogenic

0.99

MutationAssessor

Pathogenic

4.1

PhyloP100

7.8

PrimateAI

Uncertain

0.60

PROVEAN

Pathogenic

-7.4

REVEL

Pathogenic

0.65

Sift

Uncertain

0.0020

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.66

MutPred

0.56

Gain of catalytic residue at P253 (P = 0.0088)

MVP

1.0

MPC

0.54

ClinPred

1.0

GERP RS

5.2

Varity_R

0.91

gMVP

0.87

Mutation Taster

=44/56

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over