17-80108536-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP3PM2_SupportingPM5_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000152.5:c.1123 C>T variant in GAA is a missense variant predicted to cause substitution of arginine by cysteine at amino acid 375 (p.Arg375Cys). This variant has been detected in six individuals with abnormal newborn screening. Six patients with this variant had documented GAA deficiency with activity in the affected range in muscle, cultured skin fibroblasts, leukocytes, lymphocytes, whole blood or dried blood spot. Of those individuals, 4 were compound heterozygous for the variant and a pathogenic variant (3 patients with c.-32-13T>G and with c.670C>T) and 3 of those were confirmed in trans by family testing (PMID:36246652, internal laboratory). One individual was homozygous for the variant. However, all patients were detected through abnormal newborn screening and there is no evidence of symptoms or diagnosis of Pompe disease. Therefore PM3 and PP4 will not be applied. The highest population minor allele frequency in gnomAD v2.1.1 is 0.0001636 (5/30554 alleles) in the South Asian population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2_Supporting (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.954 which is above the threshold of 0.7, evidence that correlates with impact to GAA function (PP3). Another missense variant[ c.1124G>T p.Arg375Leu] (PMIDs: 24158270, 22081099) in the same codon has been classified as likely pathogenic for Pompe disease by the ClinGen Lysosomal Diseases VCEP (PM5_Supporting). Expression of the variant in HEK293 cells showed 11.7% GAA enzyme activity. However, this assay does not meet the requirements for use by the ClinGen Lysosomal Diseases VCEP because this percentage is above the cut off established by the assay (11%) to be considered deficient enzyme activity. There is a ClinVar entry for this variant (Variation ID: 290225, 1 star review status) with 2 submitters classifying the variant as likely pathogenic and 3 classifying the variant as a VUS. In summary, this variant meets the criteria to be classified as a variant of uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel (specifications Version 2.0): PM2_Supporting, PM5_Supporting, PP3.(Classification approved by the ClinGen Lysosomal Diseases VCEP on Oct. 3, 2023) LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815176/MONDO:0009290/010

Frequency

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

Exomes 𝑓: 0.000037 ( 0 hom. )

Consequence

GAA
NM_000152.5 missense

Scores

Clinical Significance

Uncertain significance reviewed by expert panel P:4U:4

Conservation

PhyloP100: 7.39

Publications

5 publications found

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 Gene-Disease associations (from GenCC):

glycogen storage disease II
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, ClinGen, Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine
glycogen storage disease due to acid maltase deficiency, infantile onset
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
glycogen storage disease due to acid maltase deficiency, late-onset
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

GAA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2

For more information check the summary or visit ClinGen Evidence Repository.

PM5

For more information check the summary or visit ClinGen Evidence Repository.

PP3

For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000152.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
GAA	NM_000152.5	MANE Select	c.1123C>T	p.Arg375Cys	missense	Exon 7 of 20	NP_000143.2	P10253
GAA	NM_001079803.3		c.1123C>T	p.Arg375Cys	missense	Exon 8 of 21	NP_001073271.1	P10253
GAA	NM_001079804.3		c.1123C>T	p.Arg375Cys	missense	Exon 7 of 20	NP_001073272.1	P10253

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
GAA	ENST00000302262.8	TSL:1 MANE Select	c.1123C>T	p.Arg375Cys	missense	Exon 7 of 20	ENSP00000305692.3	P10253
GAA	ENST00000390015.7	TSL:1	c.1123C>T	p.Arg375Cys	missense	Exon 8 of 21	ENSP00000374665.3	P10253
GAA	ENST00000933406.1		c.1123C>T	p.Arg375Cys	missense	Exon 7 of 20	ENSP00000603465.1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000362

AC:

AN:

248608

AF XY:

0.0000519

show subpopulations

Gnomad AFR exome

AF:

0.000125

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000893

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.0000370

AC:

AN:

1460664

Hom.:

Cov.:

AF XY:

0.0000468

AC XY:

AN XY:

726624

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.00

AC:

AN:

44698

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26120

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39696

South Asian (SAS)

AF:

0.000128

AC:

AN:

86228

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52442

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000333

AC:

AN:

1111888

Other (OTH)

AF:

0.0000828

AC:

AN:

60356

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.477

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74346

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41440

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000142

Hom.:

Bravo

AF:

0.0000189

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.000454

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000659

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:reviewed by expert panel

View on ClinVar

Pathogenic

VUS

Benign

Condition

Glycogen storage disease, type II (6)

not provided (2)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.37

BayesDel_addAF

Pathogenic

0.32

BayesDel_noAF

Pathogenic

0.51

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.97

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.84

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

0.99

M_CAP

Pathogenic

0.82

MetaRNN

Pathogenic

0.98

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.1

PhyloP100

7.4

PrimateAI

Uncertain

0.69

PROVEAN

Pathogenic

-7.6

REVEL

Pathogenic

0.95

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.97

MVP

1.0

MPC

0.63

ClinPred

1.0

GERP RS

4.8

Varity_R

0.98

gMVP

0.96

Mutation Taster

=12/88

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over