rs766680292

Positions:

chr17-80110785-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP4PM3_Supporting

This summary comes from the ClinGen Evidence Repository: This variant, c.1496G>A (p.Trp499Ter) is a nonsense variant which is predicted to cause nonsense mediated decay resulting in lack of gene product. This is supported by the absence of cross reactive immunological material in cultured skin fibroblasts from a patient with this variant (PMIDs 19775921, 22252923, and 25741864). Therefore, PVS1 can be applied. This patient, who has infantile onset Pompe disease, meets the ClinGen LSD VCEP’s specifications for PP4, and is homozygous for the variant, meeting PM3_Supporting. Additional patients have been reported, including 2 homozygous Tunisian patients (PMID 32125626), but the residual GAA activity was not provided, and this data was not included. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00003 in the Latino population, which meets PM2. There is a ClinVar entry for this variant (Variation ID 556959, 1 star review status), with one submitter classifying the variant as pathogenic and one as likely pathogenic. In summary, this variant meets the criteria to be classified as pathogenic for Pompe disease. ACMG/AMP criteria met, based on the specifications of the ClinGen LSD VCEP: PVS1, PM2, PM3_Supporting, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815357/MONDO:0009290/010

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GAA
NM_000152.5 stop_gained

Scores

Clinical Significance

Pathogenic reviewed by expert panel P:5

Conservation

PhyloP100: 9.39

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 Pathogenic. Variant got 12 ACMG points.

PVS1

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

PM2

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

PM3

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

PP4

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.1496G>A	p.Trp499Ter	stop_gained	10/20	ENST00000302262.8	NP_000143.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8 linkuse as main transcript	c.1496G>A	p.Trp499Ter	stop_gained	10/20	1	NM_000152.5	ENSP00000305692	P1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251198

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135856

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

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:

6.84e-7

AC:

AN:

1461844

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727224

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

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

Cov.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Glycogen storage disease, type II

Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Nov 22, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 31, 2023	This sequence change creates a premature translational stop signal (p.Trp499*) in the GAA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GAA are known to be pathogenic (PMID: 18425781, 22252923). This variant is present in population databases (rs766680292, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with Pompe disease (PMID: 18425781). ClinVar contains an entry for this variant (Variation ID: 556959). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Mar 01, 2018	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Oct 05, 2020	This variant, c.1496G>A (p.Trp499Ter) is a nonsense variant which is predicted to cause nonsense mediated decay resulting in lack of gene product. This is supported by the absence of cross reactive immunological material in cultured skin fibroblasts from a patient with this variant (PMIDs 19775921, 22252923, and 25741864). Therefore, PVS1 can be applied. This patient, who has infantile onset Pompe disease, meets the ClinGen LSD VCEP's specifications for PP4, and is homozygous for the variant, meeting PM3_Supporting. Additional patients have been reported, including 2 homozygous Tunisian patients (PMID 32125626), but the residual GAA activity was not provided, and this data was not included. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00003 in the Latino population, which meets PM2. There is a ClinVar entry for this variant (Variation ID 556959, 1 star review status), with one submitter classifying the variant as pathogenic and one as likely pathogenic. In summary, this variant meets the criteria to be classified as pathogenic for Pompe disease. ACMG/AMP criteria met, based on the specifications of the ClinGen LSD VCEP: PVS1, PM2, PM3_Supporting, PP4. -
Pathogenic, criteria provided, single submitter	curation	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Jan 23, 2020	The p.Trp499Ter variant in GAA has been reported in at least 3 individuals with glycogen storage disease (PMID: 19775921, 18425781, 22252923) and has been identified in 0.003% (1/34586) Latino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs766680292). 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 likely pathogenic by Counsyl (Variation ID: 556959). This nonsense variant leads to a premature termination codon at position 499, which is predicted to lead to a truncated or absent protein. Loss of function of the GAA gene is an established disease mechanism in autosomal recessive glycogen storage disease. The phenotype of an individual homozygous for this variant is highly specific for glycogen storage disease based on GAA enzyme activity in fibroblasts being <1% of wild type, consistent with disease (PMID: 19775921). Additionally, the homozygous occurrence of this variant and in an individual with glycogen storage disease (PMID: 19775921) slightly increases the likelihood that the p.Trp499Ter variant is pathogenic. In summary, this variant meets criteria to be classified as pathogenic for GAA in an autosomal recessive manner based on the prediction that it causes loss of function of the GAA gene, its low frequency in the general population, and the homozygous occurrence of the variant in an affected individual. ACMG/AMP Criteria applied: PVS1, PM2, PP4, PM3_supporting (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.57

BayesDel_noAF

Pathogenic

0.66

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.99

MutationTaster

Benign

1.0

A;A

Vest4

0.89

GERP RS

5.4

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.090

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