17-80112033-C-T

Position:

• chr17-80112033-C-T

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PP4 PM3 PM2 PVS1

This summary comes from the ClinGen Evidence Repository: This variant, c.1687C>T (p.Gln563Ter), is a nonsense variant that is predicted to result in nonsense-mediated decay and lack of gene product. Therefore, PVS1 can be applied. This variant is absent in gnomAD v2.1.1, meeting PM2. It has been reported in trans with a frameshift variant in GAA, c.722_723delTT, in an individual who meets the ClinGen LSD VCEP’s specifications for PP4 (PMID 19775921). This data meets PP4 and PM3. Additional patients with this variant have been reported but were not included because the residual GAA activity was not reported and therefore PP4 cannot be assessed (PMID 25741864). There is a ClinVar entry for this variant (Variation ID: 370357, 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. LINK:https://erepo.genome.network/evrepo/ui/classification/CA16041895/MONDO:0009290/010

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: GAA NM_000152.5 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: 7.34

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]

ACMG classification

Verdict is Pathogenic. Variant got 13 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GAA	NM_000152.5	c.1687C>T	p.Gln563Ter	stop_gained	12/20	ENST00000302262.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GAA	ENST00000302262.8	c.1687C>T	p.Gln563Ter	stop_gained	12/20	1	NM_000152.5	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461724 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727194

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000108

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: reviewed by expert panel

Submissions by phenotype

Glycogen storage disease, type II Pathogenic:3

Pathogenic, reviewed by expert panel	curation	ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel	Feb 14, 2020	This variant, c.1687C>T (p.Gln563Ter), is a nonsense variant that is predicted to result in nonsense-mediated decay and lack of gene product. Therefore, PVS1 can be applied. This variant is absent in gnomAD v2.1.1, meeting PM2. It has been reported in trans with a frameshift variant in GAA, c.722_723delTT, in an individual who meets the ClinGen LSD VCEP's specifications for PP4 (PMID 19775921). This data meets PP4 and PM3. Additional patients with this variant have been reported but were not included because the residual GAA activity was not reported and therefore PP4 cannot be assessed (PMID 25741864). There is a ClinVar entry for this variant (Variation ID: 370357, 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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jan 20, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 11, 2023	This sequence change creates a premature translational stop signal (p.Gln563*) 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). This premature translational stop signal has been observed in individual(s) with Pompe disease (PMID: 11949932, 31254424). ClinVar contains an entry for this variant (Variation ID: 370357). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	47
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.97	D
MutationTaster	Benign	1.0	A;A
Vest4		0.91
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.22		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.22		Position offset: -50

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

Publications

LitVar

Other links and lift over

dbSNP: rs1057516426; hg19: chr17-78085832;