rs786204649

Variant summary

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

The NM_000642.3(AGL):​c.118C>T​(p.Gln40*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,686 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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

AGL
NM_000642.3 stop_gained

Scores

7
1
6

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.85

Publications

3 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

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 1-99861538-C-T is Pathogenic according to our data. Variant chr1-99861538-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 189045.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
AGLNM_000642.3 linkc.118C>T p.Gln40* stop_gained Exon 3 of 34 ENST00000361915.8 NP_000633.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
AGLENST00000361915.8 linkc.118C>T p.Gln40* stop_gained Exon 3 of 34 1 NM_000642.3 ENSP00000355106.3

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD2 exomes
AF:
0.00000796
AC:
2
AN:
251268
AF XY:
0.00000736
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000880
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000684
AC:
10
AN:
1461686
Hom.:
0
Cov.:
32
AF XY:
0.00000688
AC XY:
5
AN XY:
727140
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33466
American (AMR)
AF:
0.00
AC:
0
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26126
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39644
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86248
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53414
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5764
European-Non Finnish (NFE)
AF:
0.00000809
AC:
9
AN:
1111920
Other (OTH)
AF:
0.00
AC:
0
AN:
60386
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.465
Heterozygous variant carriers
0
1
2
4
5
6
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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
Cov.:
32
Alfa
AF:
0.0000123
Hom.:
0
Bravo
AF:
0.0000189
ExAC
AF:
0.0000165
AC:
2
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Glycogen storage disease type III Pathogenic:6
Sep 07, 2023
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.118C>T (p.Gln40X) results in a premature termination codon, predicted to cause absence of the protein due to nonsense mediated decay, a commonly known mechanism for disease. The variant allele was found at a frequency of 8e-06 in 251268 control chromosomes (gnomAD). c.118C>T has been reported in the literature as a biallelic genotype in at least one individual affected with Glycogen Storage Disease Type III (e.g. Laforet_2019). These data indicate that the variant is likely associated with disease. The following publication has been ascertained in the context of this evaluation (PMID: 31661040). Five submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic.

Jul 15, 2021
Genome-Nilou Lab
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Nov 05, 2014
Counsyl
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

Apr 28, 2016
Division of Human Genetics, Children's Hospital of Philadelphia
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:research

Feb 14, 2024
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.Gln40*) 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 (rs771961377, gnomAD 0.006%). This premature translational stop signal has been observed in individuals with glycogen storage disease type III (PMID: 20648714, 23430941, 25451272). ClinVar contains an entry for this variant (Variation ID: 189045). For these reasons, this variant has been classified as Pathogenic.

Jan 03, 2023
Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

PVS1, PM2, PS3

not provided Pathogenic:1
Sep 22, 2017
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Q40X nonsense variant in the AGL gene has been reported previously in individuals with glycogen storage disease type III who were also found to harbor a second AGL gene variant (Austin et al., 2012; Li et al., 2014 ). The Q40X variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. In summary, we interpret this variant as pathogenic.

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.51
D
BayesDel_noAF
Pathogenic
0.65
CADD
Pathogenic
39
DANN
Uncertain
1.0
DEOGEN2
Benign
0.0
.;.;.;.;.
Eigen
Pathogenic
1.1
Eigen_PC
Pathogenic
0.94
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Benign
0.0
.;.;.;.;.
MetaRNN
Benign
0.0
.;.;.;.;.
MutationAssessor
Benign
0.0
.;.;.;.;.
PhyloP100
7.9
PROVEAN
Benign
0.0
.;.;.;.;.
REVEL
Benign
0.0
Sift
Pathogenic
0.0
.;.;.;.;.
Sift4G
Pathogenic
0.0
.;.;.;.;.
Vest4
0.95
GERP RS
5.0
Mutation Taster
=0/200
disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs771961377; hg19: chr1-100327094; COSMIC: COSV99650206; API