rs375311693

chr17-80117109-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000152.5(GAA):c.2331G>A(p.Thr777=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000143 in 1,612,210 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: GAA NM_000152.5 splice_region, synonymous
• Scores: Splicing: ADA: 0.9567
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 1.88

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 Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.47).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GAA	NM_000152.5	c.2331G>A	p.Thr777=	splice_region_variant, synonymous_variant	16/20	ENST00000302262.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GAA	ENST00000302262.8	c.2331G>A	p.Thr777=	splice_region_variant, synonymous_variant	16/20	1	NM_000152.5	P1

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152204 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000121

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000282 AC: 7 AN: 247854 Hom.: 0 AF XY: 0.0000297 AC XY: 4 AN XY: 134594

Gnomad AFR exome AF: 0.000249

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.0000487

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000165

GnomAD4 exome AF: 0.0000123 AC: 18 AN: 1460006 Hom.: 0 Cov.: 31 AF XY: 0.0000138 AC XY: 10 AN XY: 726328

Gnomad4 AFR exome AF: 0.000149

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000580

Gnomad4 FIN exome AF: 0.0000387

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152204 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74354

Gnomad4 AFR AF: 0.000121

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000547 Hom.: 0

Bravo AF: 0.0000453

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Glycogen storage disease, type II Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 05, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jul 12, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jul 22, 2022	This sequence change affects codon 777 of the GAA mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the GAA protein. This variant also falls at the last nucleotide of exon 16, which is part of the consensus splice site for this exon. This variant is present in population databases (rs375311693, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with GAA-related conditions. ClinVar contains an entry for this variant (Variation ID: 574387). 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 create or strengthen a 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. -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Oct 28, 2019	- -

not provided Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Nov 15, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	May 03, 2022	PM2 -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jun 01, 2021	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.47
Cadd	Benign	22
Dann	Benign	0.81

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.96
dbscSNV1_RF	Benign	0.64
SpliceAI score (max)		0.39		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.39		Position offset: -16

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

Publications

LitVar

Other links and lift over

dbSNP: rs375311693; hg19: chr17-78090908;