17-42909353-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP3 PP5_Moderate

The NM_000151.4(G6PC1):c.497T>G(p.Val166Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V166A) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: G6PC1 NM_000151.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.42

Genes affected

G6PC1 (HGNC:4056): (glucose-6-phosphatase catalytic subunit 1) Glucose-6-phosphatase (G6Pase) is a multi-subunit integral membrane protein of the endoplasmic reticulum that is composed of a catalytic subunit and transporters for G6P, inorganic phosphate, and glucose. This gene (G6PC) is one of the three glucose-6-phosphatase catalytic-subunit-encoding genes in human: G6PC, G6PC2 and G6PC3. Glucose-6-phosphatase catalyzes the hydrolysis of D-glucose 6-phosphate to D-glucose and orthophosphate and is a key enzyme in glucose homeostasis, functioning in gluconeogenesis and glycogenolysis. Mutations in this gene cause glycogen storage disease type I (GSD1). This disease, also known as von Gierke disease, is a metabolic disorder characterized by severe hypoglycemia associated with the accumulation of glycogen and fat in the liver and kidneys.[provided by RefSeq, Feb 2011]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a transmembrane_region Helical (size 20) in uniprot entity G6PC1_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_000151.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-42909353-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 556681.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=1}.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.774
• PP5: Variant 17-42909353-T-G is Pathogenic according to our data. Variant chr17-42909353-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 12010.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
G6PC1	NM_000151.4	c.497T>G	p.Val166Gly	missense_variant	4/5	ENST00000253801.7
G6PC1	NM_001270397.2	c.420T>G	p.Cys140Trp	missense_variant	4/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
G6PC1	ENST00000253801.7	c.497T>G	p.Val166Gly	missense_variant	4/5	1	NM_000151.4	P1
G6PC1	ENST00000592383.5	c.420T>G	p.Cys140Trp	missense_variant	4/5	2
G6PC1	ENST00000585489.1	c.447-1562T>G		intron_variant		5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease due to glucose-6-phosphatase deficiency type IA Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Oct 31, 1997	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Apr 12, 2023	For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects G6PC function (PMID: 11739393). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt G6PC protein function. ClinVar contains an entry for this variant (Variation ID: 12010). This missense change has been observed in individual(s) with glycogen storage disease type 1a (PMID: 7623438). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 166 of the G6PC protein (p.Val166Gly). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.77
BayesDel_addAF	Uncertain	0.050	T
BayesDel_noAF	Pathogenic	0.34
Cadd	Pathogenic	28
Dann	Uncertain	1.0
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Benign	0.24	T
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	0.77	D
MutationTaster	Benign	1.0	A;A;A
Sift4G	Uncertain	0.029	D
Vest4		0.48
MVP		0.98
ClinPred		1.0	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs104894571; hg19: chr17-41061370;