rs144731405

Positions:

• chr17-80112651-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000152.5:GAA:c.1828G>A variant in GAA is a missense variant predicted to cause substitution of Ala by Thr at amino acid 610 (p.Ala610Thr). Two patients with this variant have been reported in the literature (PMID:32504392, 35775064). However, because the diagnosis of Pompe disease was unclear for both patients, neither PP4 nor PM3 was applied. One of these patients, a 4-year-old girl with IOPD identified as homozygous for GAA:c.1828G>A, was also diagnosed with congenital myasthenia syndrome type 5. Because her symptoms, which included bradycardia, poor suckling, respiratory distress, respiratory failure, subglottic stenosis, and tachypnea, could be related to congenital myasthenia syndrome and not Pompe disease, and GAA activity was unavailable, this data was not used as evidence to support pathogenicity of the variant. Another individual was reported to be compound heterozygous for c.1828G>A and c.1966-1968del, but clinical information regarding the presence or absence of clinical symptoms of Pompe disease, and GAA activity was unavailable. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00017 (1/5976 alleles) in the Other population, which is lower than the ClinGen LSD VCEP’s threshold for PM2_Supporting (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.641 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function (neither PP3 nor BP4 is met), and the computational splicing predictor SpliceAI gives a score of 0.00 for donor/acceptor loss suggesting that the variant has no impact on splicing. Another missense variant c.1829C>T (p.Ala610Val) in the same codon has been reported (PMID:21484825, 17643989). However, this variant has not yet met the criteria to be classified as pathogenic or likely pathogenic by the ClinGen LSD VCEP (PM5 not met). There is a ClinVar entry for this variant (Variation ID: 282242, 2 star review status) with 5 submitters classifying the variant as Uncertain significance and 1 submitter classifying it as Pathogenic. In summary, this variant meets the criteria to be classified as Uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Storage Disorders Variant Curation Expert panel (specifications Version 2.0): PM2_Supporting.(Classification approved by the ClinGen LSD VCEP on Oct. 18, 2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815492/MONDO:0009290/010

• Frequency:
  • Genomes: 𝑓 0.000053 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000037 (1 hom.)
• Consequence: GAA NM_000152.5 missense
• Clinical Significance: Uncertain significance reviewed by expert panel P:1 U:8
• Conservation: PhyloP100: 4.29

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 Uncertain_significance. Variant got 1 ACMG points.

• PM2: 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.1828G>A	p.Ala610Thr	missense_variant	13/20	ENST00000302262.8	NP_000143.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8	c.1828G>A	p.Ala610Thr	missense_variant	13/20	1	NM_000152.5	ENSP00000305692	P1

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152200 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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: 0.0000882

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000286 AC: 7 AN: 244884 Hom.: 0 AF XY: 0.0000299 AC XY: 4 AN XY: 133818

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000584

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000328

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000273

Gnomad OTH exome AF: 0.000167

GnomAD4 exome AF: 0.0000370 AC: 54 AN: 1460232 Hom.: 1 Cov.: 33 AF XY: 0.0000372 AC XY: 27 AN XY: 726442

Gnomad4 AFR exome AF: 0.0000598

Gnomad4 AMR exome AF: 0.0000672

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000324

Gnomad4 OTH exome AF: 0.0000332

GnomAD4 genome AF: 0.0000525 AC: 8 AN: 152318 Hom.: 0 Cov.: 33 AF XY: 0.0000403 AC XY: 3 AN XY: 74476

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000653

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000882

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.000117 Hom.: 0

Bravo AF: 0.0000642

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000117 AC: 1

ExAC AF: 0.0000165 AC: 2

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:8

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:1 Uncertain:7

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Mar 29, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 16, 2022	This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 610 of the GAA protein (p.Ala610Thr). This variant is present in population databases (rs144731405, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with GAA-related conditions. ClinVar contains an entry for this variant (Variation ID: 282242). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Jul 14, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 27, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Pathogenic, no assertion criteria provided	clinical testing	Biochemical Molecular Genetic Laboratory, King Abdulaziz Medical City	Oct 11, 2020	- -
Uncertain significance, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Oct 18, 2022	The NM_000152.5:GAA:c.1828G>A variant in GAA is a missense variant predicted to cause substitution of Ala by Thr at amino acid 610 (p.Ala610Thr). Two patients with this variant have been reported in the literature (PMID: 32504392, 35775064). However, because the diagnosis of Pompe disease was unclear for both patients, neither PP4 nor PM3 was applied. One of these patients, a 4-year-old girl with IOPD identified as homozygous for GAA:c.1828G>A, was also diagnosed with congenital myasthenia syndrome type 5. Because her symptoms, which included bradycardia, poor suckling, respiratory distress, respiratory failure, subglottic stenosis, and tachypnea, could be related to congenital myasthenia syndrome and not Pompe disease, and GAA activity was unavailable, this data was not used as evidence to support pathogenicity of the variant. Another individual was reported to be compound heterozygous for c.1828G>A and c.1966-1968del, but clinical information regarding the presence or absence of clinical symptoms of Pompe disease, and GAA activity was unavailable. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00017 (1/5976 alleles) in the Other population, which is lower than the ClinGen LSD VCEP’s threshold for PM2_Supporting (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.641 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function (neither PP3 nor BP4 is met), and the computational splicing predictor SpliceAI gives a score of 0.00 for donor/acceptor loss suggesting that the variant has no impact on splicing. Another missense variant c.1829C>T (p.Ala610Val) in the same codon has been reported (PMID: 21484825, 17643989). However, this variant has not yet met the criteria to be classified as pathogenic or likely pathogenic by the ClinGen LSD VCEP (PM5 not met). There is a ClinVar entry for this variant (Variation ID: 282242, 2 star review status) with 5 submitters classifying the variant as Uncertain significance and 1 submitter classifying it as Pathogenic. In summary, this variant meets the criteria to be classified as Uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Storage Disorders Variant Curation Expert panel (specifications Version 2.0): PM2_Supporting. (Classification approved by the ClinGen LSD VCEP on Oct. 18, 2022). -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Aug 02, 2021	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Jul 30, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Uncertain	0.054	T
BayesDel_noAF	Uncertain	0.020
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D;D
Eigen	Benign	0.081
Eigen_PC	Benign	-0.0088
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.95	.;D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.21	D
MutationAssessor	Benign	1.8	L;L
MutationTaster	Benign	0.90	N;N
PrimateAI	Benign	0.45	T
PROVEAN	Benign	-2.2	N;N
REVEL	Uncertain	0.64
Sift	Uncertain	0.0040	D;D
Sift4G	Uncertain	0.012	D;D
Polyphen		0.89	P;P
Vest4		0.82
MVP		0.98
MPC		0.25
ClinPred		0.44	T
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.49
gMVP		0.85

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: rs144731405; hg19: chr17-78086450; COSMIC: COSV56409602; COSMIC: COSV56409602;