rs779556619

Positions:

• chr17-80112001-T-C

Variant summary

Our verdict is Pathogenic. Variant got 8 ACMG points: 8P and 0B. PP3 PM2_Supporting PS3_Moderate PM3 PP4_Moderate

This summary comes from the ClinGen Evidence Repository: The NM_000152.5: c.1655T>C variant in GAA is a missense variant predicted to cause substitution of leucine by proline at amino acid 552 (p.Leu552Pro). More than 10 individuals diagnosed with Pompe disease have been reported with this variant including at least 7 probands for whom laboratory data is published showing GAA activity in the deficient range (PMID 12923862, 18285536, 25681614, 27666774)(PP4_Moderate). Eight of these individuals were compound heterozygous for the variant and a pathogenic variant, phase unknown in all cases (PMID 12923862, 18285536, 18607768, 20033296, 25681614, 29122469 29422078, and two individuals were homozygotes (PMID 27666774)(PM3_Very strong). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00007 (European non-Finnish) which is lower than the ClinGen LSD VCEP threshold (<0.001) for PM2_Supporting. In two functional studies, this variant has been shown to result in significantly decreased GAA activity (<5%) and abnormal processing when expressed in COS cells (PMIDs 14695532, 19862843)(PS3_Moderate). The computational predictor REVEL gives a score of 0.94, which is above the threshold of 0.7, evidence that correlates with impact to GAA function (PP3). There is a ClinVar entry for this variant (Variation ID: 279811, 2 star review status) with nine submitters all classifying the variant as pathogenic. In summary, the variant meets the criteria to be classified as pathogenic for Pompe disease. ACMG/AMP criteria met, as specified by the ClinGen LSD VCEP (Specifications Version 2.0): PM3_Very Strong, PS3_Moderate, PP4_Moderate, PM2_Supporting, PP3.(Classification approved August 17, 2021) LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815429/MONDO:0009290/010

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000028 (0 hom.)
• Consequence: GAA NM_000152.5 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:18
• Conservation: PhyloP100: 7.44

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 8 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GAA	NM_000152.5	c.1655T>C	p.Leu552Pro	missense_variant	12/20	ENST00000302262.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GAA	ENST00000302262.8	c.1655T>C	p.Leu552Pro	missense_variant	12/20	1	NM_000152.5	P1

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152102 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

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: 0.0000735

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000319 AC: 8 AN: 250910 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135734

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: 0.0000705

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000281 AC: 41 AN: 1461506 Hom.: 0 Cov.: 31 AF XY: 0.0000248 AC XY: 18 AN XY: 727106

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: 0.0000342

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152102 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74300

Gnomad4 AFR AF: 0.00

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: 0.0000735

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000558 Hom.: 0

Bravo AF: 0.0000302

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.000109

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:18

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:11

Pathogenic, criteria provided, single submitter	clinical testing	KardioGenetik, Herz- und Diabeteszentrum NRW	Aug 03, 2023	- -
Pathogenic, criteria provided, single submitter	curation	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Jan 22, 2020	The p.Leu552Pro variant in GAA has been reported in 26 individuals (including 5 Italian, 5 Brazilian, 4 German, 2 Spanish, and 2 Greek individuals) with Glycogen Storage Disease II, segregated with disease in 6 affected relatives from 3 families (PMID: 12923862, 19862843, 12213618, 22658377, 16838077, 18285536, 25681614, 16917947, 14695532, 17616415, 18607768, 19588081, 24158270, 23160972), and has also been reported pathogenic (by GeneDx, EGL, Counsyl, and Integrated Genetics/Laboratory Corporation of America) in ClinVar (Variation ID: 279811). This variant has been identified in 0.007% (8/111590) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs779556619). 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.Leu552Pro variant may impact GAA processing, levels, and activity (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 reported pathogenic or likely pathogenic variants in individuals with Glycogen Storage Disease II increases the likelihood that the p.Leu552Pro variant is pathogenic (PMID: 12923862, 12213618, 16838077, 18285536, 25681614, 16917947, 24158270; Variation ID: 371622, 550327, 550355). The phenotype of an individual homozygous or compound heterozygous for this variant is highly specific for Glycogen Storage Disease II with <10% GAA activity detected in their muscle, lymphocyte, and muscle cells (PMID: 16917947, 12213618, 20033296, 12923862, 27666774, 19046416, 16838077, 24158270, 25681614, 18285536). In summary, this variant meets criteria to be classified as pathogenic for Glycogen Storage Disease II in an autosomal recessive manner based on multiple occurrences with likely pathogenic and pathogenic variants in Glycogen Storage Disease II and in vitro functional studies with COS cells transfected with this variant. ACMG/AMP Criteria applied: PM3, PS3, PM2, PP3, PP4 (Richards 2015). -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Sep 02, 2016	Variant summary: The GAA c.1655T>C (p.Leu552Pro) variant involves the alteration of a conserved nucleotide. 5/5 in silico tools predict a damaging outcome for this variant. This variant was found in 2/120282 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). The variant has been identified in many Pompe patients in the literature in homozygous and compound heterozygous state. In at least one patient with a compound heterozygous genotype, leukocyte GAA enzyme residual activity was 18.78% of normal, indicating that this variant has significantly reduced activity. Taken together, this variant is classified as pathogenic. -
Pathogenic, no assertion criteria provided	clinical testing	Counsyl	Jul 19, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 29, 2024	This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 552 of the GAA protein (p.Leu552Pro). This variant is present in population databases (rs779556619, gnomAD 0.006%). This missense change has been observed in individuals with Pompe disease (PMID: 14695532, 17616415, 18607768, 19588081, 20638881, 24158270, 25681614, 27666774). ClinVar contains an entry for this variant (Variation ID: 279811). 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, 17213836, 19862843, 25036864, 25409744). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Oct 31, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Aug 02, 2024	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Sep 07, 2021	The NM_000152.5: c.1655T>C variant in GAA is a missense variant predicted to cause substitution of leucine by proline at amino acid 552 (p.Leu552Pro). More than 10 individuals diagnosed with Pompe disease have been reported with this variant including at least 7 probands for whom laboratory data is published showing GAA activity in the deficient range (PMID 12923862, 18285536, 25681614, 27666774)(PP4_Moderate). Eight of these individuals were compound heterozygous for the variant and a pathogenic variant, phase unknown in all cases (PMID 12923862, 18285536, 18607768, 20033296, 25681614, 29122469 29422078, and two individuals were homozygotes (PMID 27666774)(PM3_Very strong). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00007 (European non-Finnish) which is lower than the ClinGen LSD VCEP threshold (<0.001) for PM2_Supporting. In two functional studies, this variant has been shown to result in significantly decreased GAA activity (<5%) and abnormal processing when expressed in COS cells (PMIDs 14695532, 19862843)(PS3_Moderate). The computational predictor REVEL gives a score of 0.94, which is above the threshold of 0.7, evidence that correlates with impact to GAA function (PP3). There is a ClinVar entry for this variant (Variation ID: 279811, 2 star review status) with nine submitters all classifying the variant as pathogenic. In summary, the variant meets the criteria to be classified as pathogenic for Pompe disease. ACMG/AMP criteria met, as specified by the ClinGen LSD VCEP (Specifications Version 2.0): PM3_Very Strong, PS3_Moderate, PP4_Moderate, PM2_Supporting, PP3. (Classification approved August 17, 2021) -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 15, 2024	- -
Pathogenic, criteria provided, single submitter	curation	Laboratory of Medical Genetics, National & Kapodistrian University of Athens	Feb 01, 2024	- -

not provided Pathogenic:7

Pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 02, 2023	Identified in multiple unrelated individuals with Pompe disease in published literature (Bodamer et al., 2002; Palermo et al., 2012; Remiche et al., 2014); Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies demonstrate a damaging effect (Flanagan et al., 2009); 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: 11949932, 22658377, 27862019, 25681614, 14695532, 18285536, 34530085, 31254424, 24158270, 22990675, 25036864, 23668440, 27666774, 25052852, 19588081, 16917947, 18607768, 29422078, 31086307, 34426522, 33560568, 33202836, 34852371, 19862843, 25687635, 12213618) -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jul 01, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Apr 26, 2018	- -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 09, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	AiLife Diagnostics, AiLife Diagnostics	Aug 20, 2021	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;D
Eigen	Pathogenic	0.76
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.88	.;D
M_CAP	Pathogenic	0.79	D
MetaRNN	Pathogenic	1.0	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.0	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.56	T
PROVEAN	Pathogenic	-6.4	D;D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.97
MutPred		0.90		Gain of sheet (P = 0.039);Gain of sheet (P = 0.039);
MVP		1.0
MPC		0.69
ClinPred		1.0	D
GERP RS		4.7
Varity_R		0.95
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs779556619; hg19: chr17-78085800;