rs767773929

chr17-80117001-C-Gchr17-80117001-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000152.5(GAA):c.2223C>G(p.Asp741Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000656 in 152,328 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D741N) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: GAA NM_000152.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.13

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_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 11 uncertain in NM_000152.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GAA	NM_000152.5	c.2223C>G	p.Asp741Glu	missense_variant	16/20	ENST00000302262.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GAA	ENST00000302262.8	c.2223C>G	p.Asp741Glu	missense_variant	16/20	1	NM_000152.5	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152210 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

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: 0.00000399 AC: 1 AN: 250932 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135802

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.00000656 AC: 1 AN: 152328 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74480

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ExAC AF: 0.00000824 AC: 1

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease, type II Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 31, 2021

This sequence change replaces aspartic acid with glutamic acid at codon 741 of the GAA protein (p.Asp741Glu). The aspartic acid residue is highly conserved and there is a small physicochemical difference between aspartic acid and glutamic acid. This variant is present in population databases (rs767773929, ExAC 0.01%). This variant has not been reported in the literature in individuals affected with GAA-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.39
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Pathogenic	0.17
Cadd	Benign	23
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D;D
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Uncertain	0.93	D
M_CAP	Pathogenic	0.51	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Uncertain	0.65	D
MutationAssessor	Uncertain	2.1	M;M
MutationTaster	Benign	0.95	D;D
PrimateAI	Uncertain	0.50	T
PROVEAN	Uncertain	-3.9	D;D
REVEL	Pathogenic	0.70
Sift	Uncertain	0.0030	D;D
Sift4G	Uncertain	0.0040	D;D
Polyphen		1.0	D;D
Vest4		0.92
MutPred		0.74		Gain of disorder (P = 0.2042);Gain of disorder (P = 0.2042);
MVP		0.96
MPC		0.50
ClinPred		0.95	D
GERP RS		3.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.71

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs767773929; hg19: chr17-78090800;