chr1-99896385-C-G

Variant names:

• chr1-99896385-C-G
• rs1233797859
• NM_000642.3:c.3359C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000642.3(AGL):​c.3359C>G​(p.Ala1120Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,457,806 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: AGL NM_000642.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.55
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.969

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AGL	NM_000642.3	c.3359C>G	p.Ala1120Gly	missense_variant	Exon 25 of 34	ENST00000361915.8	NP_000633.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AGL	ENST00000361915.8	c.3359C>G	p.Ala1120Gly	missense_variant	Exon 25 of 34	1	NM_000642.3	ENSP00000355106.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1457806 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 725472

African (AFR) AF: 0.0000898 AC: 3 AN: 33390

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26118

East Asian (EAS) AF: 0.00 AC: 0 AN: 39652

South Asian (SAS) AF: 0.00 AC: 0 AN: 86172

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53398

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1108350

Other (OTH) AF: 0.00 AC: 0 AN: 60248

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease type III Uncertain:1

Aug 09, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 1120 of the AGL protein (p.Ala1120Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with AGL-related conditions. ClinVar contains an entry for this variant (Variation ID: 526596). 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: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Benign	0.36	T;T;T;T;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;.;.;.;D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D
MetaSVM	Uncertain	0.78	D
MutationAssessor	Pathogenic	3.6	H;H;H;H;.
PhyloP100		7.5
PrimateAI	Uncertain	0.61	T
PROVEAN	Uncertain	-3.7	D;D;D;D;D
REVEL	Pathogenic	0.86
Sift	Uncertain	0.0080	D;D;D;D;D
Sift4G	Uncertain	0.012	D;D;D;D;D
Polyphen		1.0	D;D;D;D;D
Vest4		0.82
MutPred		0.87		Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);.;
MVP		0.96
MPC		0.30
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.40
gMVP		0.86
Mutation Taster		=10/90	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.15		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1233797859; hg19: chr1-100361941;