rs1555600575

Variant names:

• chr17-80110056-G-A
• rs1555600575
• NM_000152.5:c.1437+1G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM2_Supporting PVS1_Strong PM3 PP4_Moderate

This summary comes from the ClinGen Evidence Repository: This variant, c.1437+1G>A, alters the donor splice site of intron 9. Based on RT-PCR results from a patient who is compound heterozygous for the variant, this results in skipping of exon 9, which leads to an in frame deletion of p.Asp443_Lys479del (PMID 22676651), including part of the GAA catalytic barrel (PMID 22253258). Western blot analysis of protein extracted from cultured skin fibroblasts from a patient who is homozygous for the variant revealed that the patient was positive from cross-reactive immunological material, supporting that the variant results in an in-frame consequence (PMID 22252923). Based on these results, PVS1_Strong was applied. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00003 in the Latino population, meeting PM2_Supporting. Two patients with Pompe disease have been reported who are homozygous for the variant and meet the ClinGen LSD VCEP's PP4 specifications (PMID 22555271, 22252923; personal communication), meeting PM3 and PP4_Moderate. Another patient has been reported with the variant in trans with c.1076-22G>A (PMID 22676651). In trans data from this patient will be used in the assessment of c.1076-22G>A and is not included here in order to avoid a circular argument. There is a ClinVar entry for this variant (Variation ID: 555864; two star review status) with five submitters classifying the variant as pathogenic and one submitter classifying as likely pathogenic. 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_Strong, PM2_Supporting, PM3, PP4_Moderate. LINK:https://erepo.genome.network/evrepo/ui/classification/CA401366675/MONDO:0009290/010

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GAA NM_000152.5 splice_donor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic reviewed by expert panel P:8
• Conservation: PhyloP100: 9.23
• Publications: 5 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, ClinGen, Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine
• 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

Specifications for GAA are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

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.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000152.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GAA	NM_000152.5	MANE Select	c.1437+1G>A		splice_donor intron	N/A	NP_000143.2	P10253
	GAA	NM_001079803.3		c.1437+1G>A		splice_donor intron	N/A	NP_001073271.1	P10253
	GAA	NM_001079804.3		c.1437+1G>A		splice_donor intron	N/A	NP_001073272.1	P10253

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GAA	ENST00000302262.8	TSL:1 MANE Select	c.1437+1G>A		splice_donor intron	N/A	ENSP00000305692.3	P10253
	GAA	ENST00000390015.7	TSL:1	c.1437+1G>A		splice_donor intron	N/A	ENSP00000374665.3	P10253
	GAA	ENST00000933406.1		c.1437+1G>A		splice_donor intron	N/A	ENSP00000603465.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD2 exomes AF: 0.00000403 AC: 1 AN: 248246 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1459796 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726284

African (AFR) AF: 0.00 AC: 0 AN: 33456

American (AMR) AF: 0.0000224 AC: 1 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86226

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52604

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1110882

Other (OTH) AF: 0.00 AC: 0 AN: 60328

GnomAD4 genome Cov.: 34

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
6	-	-	Glycogen storage disease, type II (6)
2	-	-	not provided (2)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	27
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		9.2
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: -1

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

Other links and lift over

dbSNP: rs1555600575; hg19: chr17-78083855; COSMIC: COSV56409771; COSMIC: COSV56409771;