1-99902776-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000642.3(AGL):c.3682C>T(p.Arg1228*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000267 in 1,612,514 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R1228R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000029 ( 0 hom. )

Consequence

AGL
NM_000642.3 stop_gained

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8O:1

Conservation

PhyloP100: 2.40

Publications

6 publications found

Variant links:

Genes affected

AGL (HGNC:321): (amylo-alpha-1, 6-glucosidase, 4-alpha-glucanotransferase) This gene encodes the glycogen debrancher enzyme which is involved in glycogen degradation. This enzyme has two independent catalytic activities which occur at different sites on the protein: a 4-alpha-glucotransferase activity and a amylo-1,6-glucosidase activity. Mutations in this gene are associated with glycogen storage disease although a wide range of enzymatic and clinical variability occurs which may be due to tissue-specific alternative splicing. Alternatively spliced transcripts encoding different isoforms have been described. [provided by RefSeq, Jul 2008]

AGL Gene-Disease associations (from GenCC):

glycogen storage disease III
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Ambry Genetics, Laboratory for Molecular Medicine, Myriad Women’s Health, Orphanet, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp

AGL links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-99902776-C-T is Pathogenic according to our data. Variant chr1-99902776-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 21216.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AGL	NM_000642.3 link	c.3682C>T	p.Arg1228*	stop_gained	Exon 27 of 34	ENST00000361915.8	NP_000633.2	P35573-1A0A0S2A4E4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AGL	ENST00000361915.8 link	c.3682C>T	p.Arg1228*	stop_gained	Exon 27 of 34	1	NM_000642.3	ENSP00000355106.3		P35573-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152040

Hom.:

Cov.:

show subpopulations

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000799

AC:

AN:

250204

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000545

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000885

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000288

AC:

AN:

1460474

Hom.:

Cov.:

AF XY:

0.0000317

AC XY:

AN XY:

726580

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33446

American (AMR)

AF:

0.00

AC:

AN:

44680

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26092

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39644

South Asian (SAS)

AF:

0.00

AC:

AN:

86202

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53300

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000342

AC:

AN:

1111012

Other (OTH)

AF:

0.0000331

AC:

AN:

60338

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.438

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:

0.00000658

AC:

AN:

152040

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74262

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41404

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10570

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68004

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.625

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000141

Hom.:

Bravo

AF:

0.0000113

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Glycogen storage disease type III

Pathogenic:6Other:1

Sep 09, 2021

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Jul 15, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: AGL c.3682C>T (p.Arg1228X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 8e-06 in 250204 control chromosomes. c.3682C>T has been reported in the literature in individuals affected with Glycogen Storage Disease Type III (example, Shen_1996, Crushell_2010). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Sep 12, 2018

Illumina Laboratory Services, Illumina

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The AGL c.3682C>T (p.Arg1228Ter) variant is a stop-gained variant that is predicted to result in a premature termination of the protein. The p.Arg1228Ter variant has been reported in at least three studies in which it is found in a total of six individuals with glycogen storage disease type III including in one in a homozygous state, in at least three in a compound heterozygous state and in two in a heterozygous state with no second allele described (Lucchiari et al. 2002; Shen et al. 1996; Crushell et al. 2010). The p.Arg1228Ter variant was absent from 20 controls and is reported at a frequency of 0.000058 in the East Asian population of the Genome Aggregation Database but this is based on one allele in a region of good sequence coverage so the variant is presumed to be rare. Based on the clinical evidence and the potential impact of stop-gained variants, the p.Arg1228Ter variant is classified as pathogenic for glycogen storage disease type III. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Jan 19, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg1228*) in the AGL gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in AGL are known to be pathogenic (PMID: 19299494). This variant is present in population databases (rs113994131, gnomAD 0.006%). This premature translational stop signal has been observed in individual(s) with glycogen storage disease (PMID: 8755644, 20490926). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 21216). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Jul 15, 2021

Genome-Nilou Lab

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jun 21, 2023

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

GeneReviews

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

2039G>A, 2590C>T and 3682C>T are 3 common variants that together account for approximately 28% of pathogenic variants in persons of European origin. -

not provided

Pathogenic:2

Jun 13, 2014

Eurofins Ntd Llc (ga)

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

AGL: PVS1, PM2, PM3 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.51

BayesDel_noAF

Pathogenic

0.46

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

0.69

Eigen_PC

Uncertain

0.52

FATHMM_MKL

Uncertain

0.88

PhyloP100

2.4

Vest4

0.91

GERP RS

4.1

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.16

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over