Submissions for variant NM_000152.5(GAA):c.1754+1G>A

gnomAD frequency: 0.00001  dbSNP: rs886043399

Total submissions: 6

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	RCV001200862	SCV001371723	pathogenic	Glycogen storage disease, type II	2020-02-05	reviewed by expert panel	curation	The c.1754+1G>A variant alters the canonical donor splice site of intron 12 and is predicted to cause skipping of exon 12, which would result in a frameshift, creation of a premature stop codon, and nonsense-mediated decay. This is supported by the finding of no cross reactive immunological material in fibroblasts from a patient with this variant (PMID: 22252923). Therefore PVS1 can be applied. The variant is absent in gnomAD v2.1.1, meeting PM2. It has been reported in a patient with infantile onset Pompe disease in trans with a frameshift variant, c.722_723delTT (PMID 19775921), meeting PM3. There is a ClinVar entry for this variant (Variant ID: 286458; one star review status) with one submitter classifying the variant as likely pathogenic. In summary, this variant meets the criteria to be classified as Pathogenic for Pompe disease. GAA-specific ACMG/AMP criteria applied, as specified by the ClinGen LSD VCEP: PVS1, PM2, PM3, PP4.
Eurofins Ntd Llc (ga)	RCV000300474	SCV000339899	pathogenic	not provided	2016-03-03	criteria provided, single submitter	clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp	RCV001200862	SCV001448434	pathogenic	Glycogen storage disease, type II	2020-11-11	criteria provided, single submitter	clinical testing	Variant summary: GAA c.1754+1G>A is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5' splicing donor site. Three predict the variant weakens a 3' acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251118 control chromosomes. c.1754+1G>A has been reported in the literature in individuals affected with Glycogen Storage Disease, Type 2 (Pompe Disease), and in at least one case the patient was reported as being cross reactive immunological material (CRIM)-negative (Bali_2012, Kishnani_2010). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the variant being a null allele (PVS1), absent in the gnomad database (PM2), and present in a patient in trans with a pathogenic variant (PM3), this variant has been classified pathogenic.
Revvity Omics, Revvity	RCV000300474	SCV002023854	pathogenic	not provided	2020-11-12	criteria provided, single submitter	clinical testing
AiLife Diagnostics, AiLife Diagnostics	RCV000300474	SCV002502476	pathogenic	not provided	2021-10-06	criteria provided, single submitter	clinical testing
Invitae	RCV001200862	SCV003442419	pathogenic	Glycogen storage disease, type II	2024-01-29	criteria provided, single submitter	clinical testing	This sequence change affects a donor splice site in intron 12 of the GAA gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and 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). Disruption of this splice site has been observed in individual(s) with Pompe disease (PMID: 19775921). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 286458). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.