rs370950728

Positions:

• chr17-80105857-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2 PP3 PP4 PM3_Strong PS3

This summary comes from the ClinGen Evidence Repository: This variant, c.655G>A (p.Gly219Arg), has been reported in at least eight individuals with Pompe disease and residual GAA activity meeting the ClinGen LSD VCEP’s specifications for PP4. Of these individuals, four are compound heterozygous for the variant and another pathogenic variant in GAA, including c.-32-13T>G (PMID 21550241, 24844452), c.169C>T (p.Gln57Ter) (PMID 29124014), or c.2560C>T (p.Arg854Ter)(PMID 23266370), and one is homozygous for the variant (PMID 25139343). This in trans data meets PM3_Strong. A further three individuals are compound heterozygous for the variant and either c.1735G>A (p.Glu579Lys) (PMIDs 23601496, 31193175), c.546G>A (PMID 25037089), or c.784G>A (p.Glu262Lys) (PMID 11738358). However, the in trans data for these patients will be used in the assessment of those respective variants 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, patients with the same genotype had already been included, or no cDNA sequence change was provided for the variant (PMIDs 14695532, 18429042, 20033296, 21550241, 23787031, 25139343, 27711114, 30023291, 30155607). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00004024 in the African population, meeting PM2. When it was expressed in COS cells, this variant results in <2% wild type GAA activity and it is abnormally processed (PMIDs 14695532; 19862843), meeting PS3. The score for the REVEL in silico meta-predictor, 0.872, also supports that the variant has a deleterious impact on GAA function, meeting PP3. There is a ClinVar entry for this variant (Variation ID 189065; 2 star review status) with four submitters 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: PS3, PM2, PM3_Strong, PP3, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA274334/MONDO:0009290/010

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 34)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: GAA NM_000152.5 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:12 U:1
• Conservation: PhyloP100: 9.71

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 12 ACMG points.

• PS3: 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.
• PP3: 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	c.655G>A	p.Gly219Arg	missense_variant	3/20	ENST00000302262.8	NP_000143.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8	c.655G>A	p.Gly219Arg	missense_variant	3/20	1	NM_000152.5	ENSP00000305692	P1

Frequencies

GnomAD3 genomes AF: 0.0000591 AC: 9 AN: 152200 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.0000588

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.0000122 AC: 3 AN: 244972 Hom.: 0 AF XY: 0.00000750 AC XY: 1 AN XY: 133290

Gnomad AFR exome AF: 0.0000620

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: 0.0000178

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000963 AC: 14 AN: 1453526 Hom.: 0 Cov.: 57 AF XY: 0.00000830 AC XY: 6 AN XY: 723044

Gnomad4 AFR exome AF: 0.0000299

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: 0.0000213

Gnomad4 NFE exome AF: 0.0000108

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152200 Hom.: 0 Cov.: 34 AF XY: 0.0000403 AC XY: 3 AN XY: 74368

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.000478

Alfa AF: 0.0000334 Hom.: 0

Bravo AF: 0.0000189

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:12 Uncertain:1

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:8 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 07, 2017	Variant summary: The GAA c.655G>A (p.Gly219Arg) variant located in the Galactose mutarotase, N-terminal barrel domain (via InterPro) involves the alteration of a conserved nucleotide and 5/5 in silico tools predict a damaging outcome for this variant. This variant was found in 2/120140 control chromosomes at a frequency of 0.0000166, which does not exceed the estimated maximal expected allele frequency of a pathogenic GAA variant (0.0042205). Multiple publications have cited the variant in both compound heterozygous and homozygous Pompe disease patients, which were found to have very little GAA activity. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as "likely pathogenic/pathogenic." Taken together, this variant is classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 31, 2024	This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 219 of the GAA protein (p.Gly219Arg). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with Pompe disease, including individuals with low alpha-glucosidase enzyme activity (less than 40% of normal) (PMID: 11738358, 14695532, 18429042, 21550241, 23266370, 23601496, 23787031, 29124014). ClinVar contains an entry for this variant (Variation ID: 189065). 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%. Experimental studies have shown that this missense change affects GAA function (PMID: 14695532). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Nov 19, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Nov 11, 2021	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Feb 18, 2024	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Apr 19, 2020	This variant, c.655G>A (p.Gly219Arg), has been reported in at least eight individuals with Pompe disease and residual GAA activity meeting the ClinGen LSD VCEP's specifications for PP4. Of these individuals, four are compound heterozygous for the variant and another pathogenic variant in GAA, including c.-32-13T>G (PMID 21550241, 24844452), c.169C>T (p.Gln57Ter) (PMID 29124014), or c.2560C>T (p.Arg854Ter)(PMID 23266370), and one is homozygous for the variant (PMID 25139343). This in trans data meets PM3_Strong. A further three individuals are compound heterozygous for the variant and either c.1735G>A (p.Glu579Lys) (PMIDs 23601496, 31193175), c.546G>A (PMID 25037089), or c.784G>A (p.Glu262Lys) (PMID 11738358). However, the in trans data for these patients will be used in the assessment of those respective variants 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, patients with the same genotype had already been included, or no cDNA sequence change was provided for the variant (PMIDs 14695532, 18429042, 20033296, 21550241, 23787031, 25139343, 27711114, 30023291, 30155607). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00004024 in the African population, meeting PM2. When it was expressed in COS cells, this variant results in <2% wild type GAA activity and it is abnormally processed (PMIDs 14695532; 19862843), meeting PS3. The score for the REVEL in silico meta-predictor, 0.872, also supports that the variant has a deleterious impact on GAA function, meeting PP3. There is a ClinVar entry for this variant (Variation ID 189065; 2 star review status) with four submitters 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: PS3, PM2, PM3_Strong, PP3, PP4. -
Pathogenic, criteria provided, single submitter	curation	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Jan 22, 2020	The p.Gly219Arg variant in GAA has been reported in 22 individuals (including 10 French, 3 Saudi, 1 Italian, 1 Spanish, 1 Japanese, and 3 other Caucasian individuals) with Glycogen Storage Disease II (PMID: 23787031, 30023291, 18995995, 23266370, 11738358, 21550241, 25037089, 23601496, 21637107, 29124014, 30155607, 18429042, 24844452, 14695532), and has also been reported pathogenic (by EGL, GeneDx, Invitae, and Integrated Genetics) and likely pathogenic (by Counsyl) in ClinVar (Variation ID: 189065). This variant has been identified in 0.004% (1/24848) of African chromosomes and 0.003% (1/35388) of Latino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs370950728). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. In vitro functional studies with COS cells transfected with this variant provide some evidence that the p.Gly219Arg variant may reduce GAA activity by more than 98% (PMID: 14695532, 19862843). However, these types of assays may not accurately represent biological function. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. The presence of this variant in combination with pathogenic and likely pathogenic variants, and in individuals with Glycogen Storage Disease II increases the likelihood that the p.Gly219Arg variant is pathogenic (PMID: 21637107, 21550241, 11738358). The phenotype of individuals heterozygous for this variant is highly specific for Glycogen Storage Disease II with very low GAA activity detected in relevant tissues (PMID: 23601496, 24844452, 21550241, 29124014, 11738358, 21637107). In summary, this variant meets criteria to be classified as pathogenic for Glycogen Storage Disease II in an autosomal recessive manner based on in vitro functional studies with COS cells transfected with this variant and multiple occurrences with pathogenic GAA variants in individuals with Glycogen Storage Disease II. ACMG/AMP Criteria applied: PS3, PM2, PM3, PP3, PP4 (Richards 2015). -
Uncertain significance, criteria provided, single submitter	research	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Mar 14, 2024	- -

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Apr 13, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 14, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 07, 2023	Published functional studies demonstrate a damaging effect with significant reduction of enzyme activity (PMID: 33560568, 14695532); Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 18429042, 34501319, 33301762, 30564623, 14695532, 21550241, 23601496, 21392261, 23266370, 20033296, 11738358, 24844452, 28648663, 31086307, 29122469, 32870709, 19343043, 22253258, 33560568, 23787031) -

GAA-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 12, 2024

The GAA c.655G>A variant is predicted to result in the amino acid substitution p.Gly219Arg. This variant was reported in the homozygous and compound heterozygous state in multiple patients with clinical and biochemical features consistent with Pompe disease (Sacconi et al. 2014. PubMed ID: 24844452, Fernandez-Hojas et al. 2002. PubMed ID: 11738358, Prakalapakorn et al. 2014. PubMed ID: 25139343, Hermans et al. 2004. PubMed ID: 14695532). Functional characterization of the variant suggests it is deleterious (Hermans et al. 2004. PubMed ID: 14695532). This variant is reported in 0.0040% of alleles in individuals of African descent in gnomAD. This variant is classified as pathogenic in clinvar by the majority of submitters including the ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel (https://www.ncbi.nlm.nih.gov/clinvar/variation/189065/). This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.71
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	26
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.64	D;D;D
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;.;D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Pathogenic	3.2	.;M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-6.1	.;D;D
REVEL	Pathogenic	0.87
Sift	Uncertain	0.026	.;D;D
Sift4G	Pathogenic	0.0	D;T;T
Polyphen		1.0	.;D;D
Vest4		0.96, 0.95
MutPred		0.78		Gain of MoRF binding (P = 0.068);Gain of MoRF binding (P = 0.068);Gain of MoRF binding (P = 0.068);
MVP		0.99
MPC		0.39
ClinPred		0.98	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.94

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: rs370950728; hg19: chr17-78079656;