rs1131691438
Variant summary
Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2PP3_StrongPP5
The NM_000642.3(AGL):c.1027C>T(p.Arg343Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000187 in 1,603,438 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R343Q) has been classified as Uncertain significance.
Frequency
Consequence
NM_000642.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
AGL | NM_000642.3 | c.1027C>T | p.Arg343Trp | missense_variant | Exon 8 of 34 | ENST00000361915.8 | NP_000633.2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000671 AC: 1AN: 148962Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.00000398 AC: 1AN: 251304Hom.: 0 AF XY: 0.00000736 AC XY: 1AN XY: 135832
GnomAD4 exome AF: 0.00000138 AC: 2AN: 1454476Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1AN XY: 723596
GnomAD4 genome AF: 0.00000671 AC: 1AN: 148962Hom.: 0 Cov.: 33 AF XY: 0.0000138 AC XY: 1AN XY: 72716
ClinVar
Submissions by phenotype
Glycogen storage disease type III Pathogenic:2Uncertain:1
The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). Protein truncation variants are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.81; 3Cnet: 0.82). Same nucleotide change resulting in same amino acid change has been previously reported to be associated with AGL- related disorder (ClinVar ID: VCV000429532 / PMID: 23430490). The variant has been reported to be in trans with pathogenic variant(s) as either compound heterozygous or homozygous in at least one similarly affected unrelated individual (PMID: 23430490). Therefore, this variant is classified as likely pathogenic according to the recommendation of ACMG/AMP guideline. -
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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 AGL protein function. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Experimental studies have shown that this missense change does not substantially affect AGL function (PMID: 27088557). ClinVar contains an entry for this variant (Variation ID: 429532). This missense change has been observed in individual(s) with clinical features of glycogen storage disease (Invitae). This variant is present in population databases (no rsID available, gnomAD 0.004%). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 343 of the AGL protein (p.Arg343Trp). -
not provided Pathogenic:1
Not observed at significant frequency in large population cohorts (gnomAD); 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: 23430490, 27088557) -
not specified Uncertain:1
Variant summary: AGL c.1027C>T (p.Arg343Trp) results in a non-conservative amino acid change located in the Glycogen debranching enzyme, glucanotransferase domain of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251304 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1027C>T has been reported in the literature in an individual in the compound heterozygous state who was affected with Glycogen Storage Disease Type III (Senter_2012). These data do not allow any conclusion about variant significance. One study which expressed Candida glabrata glycogen debranching enzyme in Escherichia coli reported the variant to have no impact on glycogen debranching enzyme activity, however this data does not allow convincing conclusions about the variant effect in humans (Zhai_2016). Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Two submitters classified the variant as likely pathogenic while one classified as VUS. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at