1-42927615-T-G

Variant names:

• chr1-42927615-T-G
• rs587784392
• NM_006516.4:c.1268A>C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_006516.4(SLC2A1):​c.1268A>C​(p.Gln423Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign 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. Q423R) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SLC2A1 NM_006516.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.69

Genes affected

SLC2A1 (HGNC:11005): (solute carrier family 2 member 1) This gene encodes a major glucose transporter in the mammalian blood-brain barrier. The encoded protein is found primarily in the cell membrane and on the cell surface, where it can also function as a receptor for human T-cell leukemia virus (HTLV) I and II. Mutations in this gene have been found in a family with paroxysmal exertion-induced dyskinesia. [provided by RefSeq, Apr 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_006516.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the SLC2A1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 98 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: 2.9256 (below the threshold of 3.09). Trascript score misZ: 4.6729 (above the threshold of 3.09). GenCC associations: The gene is linked to childhood absence epilepsy, dystonia 9, epilepsy, idiopathic generalized, susceptibility to, 12, GLUT1 deficiency syndrome, myoclonic-astatic epilepsy, childhood onset GLUT1 deficiency syndrome 2, hereditary cryohydrocytosis with reduced stomatin, encephalopathy due to GLUT1 deficiency.
• BP4: Computational evidence support a benign effect (MetaRNN=0.29536217).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SLC2A1	NM_006516.4	c.1268A>C	p.Gln423Pro	missense_variant	Exon 9 of 10	ENST00000426263.10	NP_006507.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SLC2A1	ENST00000426263.10	c.1268A>C	p.Gln423Pro	missense_variant	Exon 9 of 10	1	NM_006516.4	ENSP00000416293.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Nov 25, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1268A>C (p.Q423P) alteration is located in exon 9 (coding exon 9) of the SLC2A1 gene. This alteration results from an A to C substitution at nucleotide position 1268, causing the glutamine (Q) at amino acid position 423 to be replaced by a proline (P). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is well conserved in available vertebrate species. The in silico prediction for this alteration is inconclusive. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

GLUT1 deficiency syndrome 1, autosomal recessive Uncertain:1

Sep 03, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamine with proline at codon 423 of the SLC2A1 protein (p.Gln423Pro). The glutamine residue is moderately conserved and there is a moderate physicochemical difference between glutamine and proline. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with SLC2A1-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 tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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	Benign	0.066
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Benign	21
DANN	Benign	0.21
DEOGEN2	Benign	0.37	T
Eigen	Benign	-0.56
Eigen_PC	Benign	-0.22
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.89	D
M_CAP	Benign	0.028	D
MetaRNN	Benign	0.30	T
MetaSVM	Benign	-0.74	T
MutationAssessor	Benign	-0.70	N
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	2.6	N
REVEL	Uncertain	0.31
Sift	Benign	1.0	T
Sift4G	Benign	1.0	T
Polyphen		0.0010	B
Vest4		0.47
MutPred		0.62		Gain of relative solvent accessibility (P = 0.1571);
MVP		0.96
MPC		1.1
ClinPred		0.66	D
GERP RS		5.8
Varity_R		0.39
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs587784392; hg19: chr1-43393286;