rs1553188589

Variant names:

• chr1-99891357-G-GT
• rs1553188589
• NM_000642.3:c.2949+2dupT

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000642.3(AGL):​c.2949+2dupT variant causes a splice region, intron change. The variant allele was found at a frequency of 0.000000684 in 1,461,326 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: AGL NM_000642.3 splice_region, intron
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 3.87
• 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: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AGL	NM_000642.3	c.2949+2dupT		splice_region_variant, intron_variant	Intron 22 of 33	ENST00000361915.8	NP_000633.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AGL	ENST00000361915.8	c.2949+1_2949+2insT		splice_donor_variant, intron_variant	Intron 22 of 33	1	NM_000642.3	ENSP00000355106.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461326 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726954

African (AFR) AF: 0.00 AC: 0 AN: 33464

American (AMR) AF: 0.00 AC: 0 AN: 44702

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.00 AC: 0 AN: 39668

South Asian (SAS) AF: 0.00 AC: 0 AN: 86244

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53318

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111686

Other (OTH) AF: 0.00 AC: 0 AN: 60382

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Glycogen storage disease type III Uncertain:4

Jul 15, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 17, 2017

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

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. -

Mar 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 22 of the AGL gene. It does not directly change the encoded amino acid sequence of the AGL protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with glycogen storage disease (PMID: 27106217). ClinVar contains an entry for this variant (Variation ID: 551550). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). 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. -

Dec 17, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.9
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.32		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.32		Position offset: -1

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

Other links and lift over

dbSNP: rs1553188589; hg19: chr1-100356913;