17-80107589-C-A

Position:

chr17-80107589-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000152.5:c.725C>A variant in GAA is a missense variant predicted to cause substitution of Ala by Glu at amino acid 242 (p.Ala242Glu). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00028 (7/24910 alleles) in the African population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2 (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.528 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function (neither PP3 nor BP4 is met). It has not been reported in the literature as causative for GAA-related disease, but has been observed in 9 asymptomatic newborn screening cases by a clinical testing laboratory cases. In those cases, the c.1630G>A (p.Val544Met) variant (ClinVar Variation ID; 450358), classified as a variant of uncertain significance by the ClinGen LD VCEP on June 6, 2024), was always present suggesting that the two variants are in cis. There is a ClinVar entry for this variant (Variation ID: 642648). In summary, this variant meets the criteria to be classified as Uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel (specifications Version 2.0): PM2_supporting.(Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on May 21, 2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815003/MONDO:0009290/010

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 34)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

GAA
NM_000152.5 missense

Scores

Clinical Significance

Uncertain significance reviewed by expert panel U:8

Conservation

PhyloP100: 7.77

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:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM2

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.725C>A	p.Ala242Glu	missense_variant	4/20	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.725C>A	p.Ala242Glu	missense_variant	4/20	1	NM_000152.5	ENSP00000305692.3		P10253

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152112

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000193

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:

0.0000159

AC:

AN:

251102

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135854

show subpopulations

Gnomad AFR exome

AF:

0.000246

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:

0.00000411

AC:

AN:

1460914

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726778

show subpopulations

Gnomad4 AFR exome

AF:

0.000179

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152112

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74302

show subpopulations

Gnomad4 AFR

AF:

0.000193

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

Alfa

AF:

0.0000296

Hom.:

Bravo

AF:

0.0000756

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:8

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Glycogen storage disease, type II

Uncertain:5

Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jul 26, 2021	- -
Uncertain significance, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	May 21, 2024	The NM_000152.5:c.725C>A variant in GAA is a missense variant predicted to cause substitution of Ala by Glu at amino acid 242 (p.Ala242Glu). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00028 (7/24910 alleles) in the African population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2 (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.528 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function (neither PP3 nor BP4 is met). It has not been reported in the literature as causative for GAA-related disease, but has been observed in 9 asymptomatic newborn screening cases by a clinical testing laboratory cases. In those cases, the c.1630G>A (p.Val544Met) variant (ClinVar Variation ID; 450358), classified as a variant of uncertain significance by the ClinGen LD VCEP on June 6, 2024), was always present suggesting that the two variants are in cis. There is a ClinVar entry for this variant (Variation ID: 642648). In summary, this variant meets the criteria to be classified as Uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel (specifications Version 2.0): PM2_supporting. (Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on May 21, 2024). -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 30, 2023	This sequence change replaces alanine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 242 of the GAA protein (p.Ala242Glu). This variant is present in population databases (rs745861849, gnomAD 0.03%). 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: 642648). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on GAA protein function. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 05, 2021	- -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 27, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Dec 21, 2020	- -

GAA-related disorder

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 08, 2023

The GAA c.725C>A variant is predicted to result in the amino acid substitution p.Ala242Glu. To our knowledge, this variant has not been reported in the literature. Two variants affecting the same amino acid residue (c.725C>T Ala242Val and c.726G>A Ala242Ala) have been reported in individuals with glycogen storage disease 2 (c.725C>T Ala242Val reported in Kroos et al 2008. PubMed ID: 18425781; c.726G>A Ala242Ala reported in Gragnaniello et al 2022. PubMed ID: 36310651). This variant is reported in 0.028% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/17-78081388-C-A). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.55

BayesDel_addAF

Benign

-0.0093

BayesDel_noAF

Uncertain

0.040

CADD

Uncertain

DANN

Uncertain

0.98

DEOGEN2

Uncertain

0.52

D;D;D

Eigen

Benign

-0.042

Eigen_PC

Benign

0.0061

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

D;.;D

M_CAP

Uncertain

0.093

MetaRNN

Uncertain

0.57

D;D;D

MetaSVM

Benign

-0.55

MutationAssessor

Benign

1.3

.;L;L

PrimateAI

Uncertain

0.67

PROVEAN

Uncertain

-3.4

.;D;D

REVEL

Uncertain

0.53

Sift

Benign

0.046

.;D;D

Sift4G

Uncertain

0.011

D;T;T

Polyphen

0.64

.;P;P

Vest4

0.69

MVP

0.94

MPC

0.29

ClinPred

0.63

GERP RS

5.2

Varity_R

0.88

gMVP

0.90

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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