rs886043920

Variant names:

• chr17-80107598-TC-T
• rs886043920
• NM_000152.5:c.736delC

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM2_Supporting PVS1

This summary comes from the ClinGen Evidence Repository: The NM_000152.5:c.736del (p.Leu246PhefsTer22) variant in GAA is a frameshift variant predicted to cause a premature stop codon leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1). The variant is absent in gnomAD v2.1.1. (PM2_Supporting). One patient with limb girdle muscular dystrophy was reported to be compound heterozygous for c.736delC and another variant in GAA that has been classified by the ClinGen LD VCEP as pathogenic, c.546G>A; the phase is unknown. However, because no aditional information is available to support the diagnosis of Pompe disease, such as GAA deficiency, there is insufficient evidence to apply PM3 at this time. . There is a ClinVar entry for this variant (Variation ID: 288505. In summary, this variant meets the criteria to be classified as likely pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP Specifications Version 2.0): PVS1, PM2_Supporting.(Classification approved by the ClinGen Lysosomal Diseases VCEP on July 18, 2023). LINK:https://erepo.genome.network/evrepo/ui/classification/CA10606113/MONDO:0009290/010

• Frequency: Genomes: not found (cov: 34)
• Consequence: GAA NM_000152.5 frameshift
• Clinical Significance: Likely pathogenic reviewed by expert panel P:5
• Conservation: PhyloP100: 0.216
• Publications: 1 publications found

Genes affected

GAA (HGNC:4065): (alpha glucosidase) This gene encodes lysosomal alpha-glucosidase, which is essential for the degradation of glycogen to glucose in lysosomes. The encoded preproprotein is proteolytically processed to generate multiple intermediate forms and the mature form of the enzyme. Defects in this gene are the cause of glycogen storage disease II, also known as Pompe's disease, which is an autosomal recessive disorder with a broad clinical spectrum. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016]

GAA Gene-Disease associations (from GenCC):

• glycogen storage disease II

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), PanelApp Australia, ClinGen, G2P
• glycogen storage disease due to acid maltase deficiency, infantile onset

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• glycogen storage disease due to acid maltase deficiency, late-onset

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GAA	NM_000152.5	c.736delC	p.Leu246PhefsTer22	frameshift_variant	Exon 4 of 20	ENST00000302262.8	NP_000143.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAA	ENST00000302262.8	c.736delC	p.Leu246PhefsTer22	frameshift_variant	Exon 4 of 20	1	NM_000152.5	ENSP00000305692.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 34

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:4

Feb 12, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 18, 2023

ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000152.5:c.736del (p.Leu246PhefsTer22) variant in GAA is a frameshift variant predicted to cause a premature stop codon leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1). The variant is absent in gnomAD v2.1.1. (PM2_Supporting). One patient with limb girdle muscular dystrophy was reported to be compound heterozygous for c.736delC and another variant in GAA that has been classified by the ClinGen LD VCEP as pathogenic, c.546G>A; the phase is unknown. However, because no aditional information is available to support the diagnosis of Pompe disease, such as GAA deficiency, there is insufficient evidence to apply PM3 at this time. . There is a ClinVar entry for this variant (Variation ID: 288505. In summary, this variant meets the criteria to be classified as likely pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP Specifications Version 2.0): PVS1, PM2_Supporting. (Classification approved by the ClinGen Lysosomal Diseases VCEP on July 18, 2023). -

Jun 28, 2022

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.Leu246Phefs*22) in the GAA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GAA are known to be pathogenic (PMID: 18425781, 22252923). This variant is not present in population databases (gnomAD no frequency). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 288505). This variant has not been reported in the literature in individuals affected with GAA-related conditions. -

Mar 18, 2016

Counsyl

Significance: Likely pathogenic

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. -

not provided Pathogenic:1

Jun 06, 2016

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.22

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.11		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: rs886043920; hg19: chr17-78081397;