17-80112648-T-TA

Position:

chr17-80112648-T-TA

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM3PVS1PM2PP4

This summary comes from the ClinGen Evidence Repository: This variant, c.1826dup (p.Tyr609Terfs), is predicted to cause a frameshift, premature termination codon, and nonsense mediated decay resulting in lack of gene product. This is supported by the absence of cross-reactive immunological material in cultured fibroblasts from a patient with the variant (PMID 22252923). Therefore, PVS1 can be applied. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00001816 in the European non-Finnish population, meeting PM2. Two individuals meeting the ClinGen LSD VCEP’s specifications for PP4 have been reported who are compound heterozygous for the variant and a unique pathogenic variant; one of these patients is compound heterozygous for the variant and c.525delT, and the other patient is compound heterozygous for the variant and c.2238G>A (p.Trp746Ter) (PMIDs 12897283, 25741864). Therefore, PP4 and PM3 can be applied. Another patient was reported who is compound heterozygous for this variant and a known pathogenic variant (c.525delT), but this data was not included because the GAA activity for the patient was not reported (PMID 14695532). 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, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA274414/MONDO:0009290/010

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

GAA
NM_000152.5 stop_gained, frameshift

Scores

Not classified

Clinical Significance

Pathogenic reviewed by expert panel P:7

Conservation

PhyloP100: 2.23

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 13 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.1826dup	p.Tyr609Ter	stop_gained, frameshift_variant	13/20	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.1826dup	p.Tyr609Ter	stop_gained, frameshift_variant	13/20	1	NM_000152.5	ENSP00000305692	P1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152232

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

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:

0.00000816

AC:

AN:

245124

Hom.:

AF XY:

0.00

AC XY:

AN XY:

133966

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000182

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000548

AC:

AN:

1460378

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

726522

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

0.00000720

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152232

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74364

show subpopulations

Gnomad4 AFR

AF:

0.0000482

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:

0.00000378

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Glycogen storage disease, type II

Pathogenic:5

Pathogenic, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Feb 14, 2020	This variant, c.1826dup (p.Tyr609Terfs), is predicted to cause a frameshift, premature termination codon, and nonsense mediated decay resulting in lack of gene product. This is supported by the absence of cross-reactive immunological material in cultured fibroblasts from a patient with the variant (PMID 22252923). Therefore, PVS1 can be applied. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00001816 in the European non-Finnish population, meeting PM2. Two individuals meeting the ClinGen LSD VCEP's specifications for PP4 have been reported who are compound heterozygous for the variant and a unique pathogenic variant; one of these patients is compound heterozygous for the variant and c.525delT, and the other patient is compound heterozygous for the variant and c.2238G>A (p.Trp746Ter) (PMIDs 12897283, 25741864). Therefore, PP4 and PM3 can be applied. Another patient was reported who is compound heterozygous for this variant and a known pathogenic variant (c.525delT), but this data was not included because the GAA activity for the patient was not reported (PMID 14695532). 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, PP4. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Jan 27, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 27, 2023	For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 189144). This premature translational stop signal has been observed in individual(s) with Pompe disease (PMID: 12897283, 24269976, 25846667, 29124014). This variant is present in population databases (rs754952153, gnomAD 0.002%). This sequence change creates a premature translational stop signal (p.Tyr609*) 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). -
Pathogenic, criteria provided, single submitter	curation	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Jan 22, 2020	The p.Tyr609Ter variant in GAA has been reported in at least 4 individuals (including at least 1 Dutch individual) with Glycogen Storage Disease II (PMID: 14695532, 12897283, 25741864, 22252923), and has also been reported likely pathogenic by Counsyl and pathogenic by EGL Genetic Diagnostics in ClinVar (Variation ID: 189144). This variant has been identified in 0.00002% (2/110126) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs778892297). 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 leads to a premature termination codon at position 609, 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 II. The presence of this variant in combination with reported pathogenic variants and in individuals with Glycogen Storage Disease II increases the likelihood that the p.Tyr609Ter variant is pathogenic (PMID: 25741864, 12897283). Another pathogenic variant, c.1827delC (p.Tyr609Ter), has been reported with the same position and amino acid change (PMID: 14695532, 26693141). The phenotype of individuals heterozygous for this variant is highly specific for Glycogen Storage Disease II based on multiple reports of this variant in CRIM-negative cohorts and abnormally low GAA activity detected in the fibroblasts of one individual heterozygous for this variant (PMID: 22252923, 25741864, 12897283). In summary, this variant meets criteria to be classified as pathogenic for Glycogen Storage Disease II in an autosomal recessive manner based on the predicted impact of the variant and multiple occurrences with pathogenic GAA variants in individuals with Glycogen Storage Disease II. ACMG/AMP Criteria applied: PVS1, PM3, PM2, PP4 (Richards 2015). -
Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Jan 22, 2015	- -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 20, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jul 25, 2023	Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies demonstrate a damaging effect via a mouse model homozygous knock-in for the p.(Y609X) variant that has features of Infantile-onset Pompe Disease (IOPD) (Huang et al., 2020); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 31254424, 33301762, 12897283, 25846667, 29124014, 32587263) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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