17-80105775-C-A

Position:

• chr17-80105775-C-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PP4 PM2 PVS1

This summary comes from the ClinGen Evidence Repository: This variant, c.573C>A (p.Tyr191Ter), is a nonsense variant that is predicted to result in nonsense-mediated decay and lack of gene product, meeting PVS1. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00003 in the Latino population, meeting PM2. Two patients meeting the ClinGen LSD VCEP's specifications for PP4 have been reported. These patients are compound heterozygous for the variant and either c.2173C>T (p.Arg725Trp) (PMID 18505979), or c.2646+2T>A (PMID 11738358). However, in both cases, the in trans data from these patients will be used in the classification of the other variant and was not included here in order to avoid a circular argument. Additional patients have been reported but were not included because the residual GAA activity was not reported and therefore PP4 cannot be assessed (PMIDs 25998610, 27711114, 30022036). There is a ClinVar entry for this variant (Variation ID: 370276; 1 star review status) with one submitter classifying the variant as likely pathogenic. In summary, this variant meets the criteria to be classified as pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP: PVS1, PM2, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA16041885/MONDO:0009290/010

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GAA NM_000152.5 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:8
• Conservation: PhyloP100: -1.75

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]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GAA	NM_000152.5	c.573C>A	p.Tyr191Ter	stop_gained	3/20	ENST00000302262.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GAA	ENST00000302262.8	c.573C>A	p.Tyr191Ter	stop_gained	3/20	1	NM_000152.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249708 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135242

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: 0.00000205 AC: 3 AN: 1460026 Hom.: 0 Cov.: 54 AF XY: 0.00000275 AC XY: 2 AN XY: 726404

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:7

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 14, 2023	This sequence change creates a premature translational stop signal (p.Tyr191*) 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 (no rsID available, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with Pompe disease (PMID: 11738358, 30155607). ClinVar contains an entry for this variant (Variation ID: 370276). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jan 04, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Dec 07, 2021	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Aug 12, 2020	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	May 19, 2020	This variant, c.573C>A (p.Tyr191Ter), is a nonsense variant that is predicted to result in nonsense-mediated decay and lack of gene product, meeting PVS1. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00003 in the Latino population, meeting PM2. Two patients meeting the ClinGen LSD VCEP's specifications for PP4 have been reported. These patients are compound heterozygous for the variant and either c.2173C>T (p.Arg725Trp) (PMID 18505979), or c.2646+2T>A (PMID 11738358). However, in both cases, the in trans data from these patients will be used in the classification of the other variant and was not included here in order to avoid a circular argument. Additional patients have been reported but were not included because the residual GAA activity was not reported and therefore PP4 cannot be assessed (PMIDs 25998610, 27711114, 30022036). There is a ClinVar entry for this variant (Variation ID: 370276; 1 star review status) with one submitter classifying the variant as likely pathogenic. In summary, this variant meets the criteria to be classified as pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP: PVS1, PM2, PP4. -
Pathogenic, criteria provided, single submitter	curation	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Jan 22, 2020	The p.Tyr191Ter variant in GAA has been reported in 3 Spanish and 1 French individuals with Glycogen Storage Disease II (PMID: 11738358, 18505979, 25998610), and has also been reported likely pathogenic by Counsyl in ClinVar (Variation ID: 370276). This variant has been identified in 0.003% (1/34578) of Latino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs376229714). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This nonsense variant leads to a premature termination codon at position 191, 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. This variant has been seen in combination with other variants curated in individuals with Glycogen Storage Disease II (PMID: 11738358, 18505979). The phenotype of individuals compound heterozygous for this variant is highly specific for Glycogen Storage Disease II based on low GAA activity in patients consistent with disease (PMID: PMID: 18505979, 11738358). 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 low frequency in the general population. ACMG/AMP Criteria applied: PVS1, PP4, PM2 (Richards 2015). -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Sep 20, 2023	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Revvity Omics, Revvity

Jul 28, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	34
DANN	Uncertain	0.98
Eigen	Benign	-0.36
Eigen_PC	Benign	-0.72
FATHMM_MKL	Benign	0.33	N
MutationTaster	Benign	1.0	A;A
Vest4		0.79
GERP RS		-6.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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

Other links and lift over

dbSNP: rs376229714; hg19: chr17-78079574;