2-69345903-C-T

Position:

• chr2-69345903-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_001244710.2(GFPT1):​c.1105+1G>A variant causes a splice donor 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: GFPT1 NM_001244710.2 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.82

Genes affected

GFPT1 (HGNC:4241): (glutamine--fructose-6-phosphate transaminase 1) This gene encodes the first and rate-limiting enzyme of the hexosamine pathway and controls the flux of glucose into the hexosamine pathway. The product of this gene catalyzes the formation of glucosamine 6-phosphate. [provided by RefSeq, Sep 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.045238096 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-69345903-C-T is Pathogenic according to our data. Variant chr2-69345903-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 540351.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GFPT1	NM_001244710.2	c.1105+1G>A		splice_donor_variant		ENST00000357308.9	NP_001231639.1
GFPT1	NM_002056.4	c.1051+1G>A		splice_donor_variant			NP_002047.2
GFPT1	XM_017003801.2	c.1180+1G>A		splice_donor_variant			XP_016859290.1
GFPT1	XM_017003802.3	c.1126+1G>A		splice_donor_variant			XP_016859291.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GFPT1	ENST00000357308.9	c.1105+1G>A		splice_donor_variant		5	NM_001244710.2	ENSP00000349860
GFPT1	ENST00000361060.5	c.1051+1G>A		splice_donor_variant		1		ENSP00000354347	P1
GFPT1	ENST00000674438.1	c.835+1G>A		splice_donor_variant				ENSP00000501469
GFPT1	ENST00000674507.1	c.1051+1G>A		splice_donor_variant				ENSP00000501332

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 19

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myasthenic syndrome 12 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 03, 2017

This variant is not present in population databases (ExAC no frequency). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in GFPT1 are known to be pathogenic (PMID: 23794683). This variant has not been reported in the literature in individuals with GFPT1-related disease. This sequence change affects a donor splice site in intron 11 of the GFPT1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. The GFTP1 gene has multiple clinically relevant isoforms. The c.1051+1G>A variant in the primary transcript (NM_002056.3) corresponds to position c.1105+1G>A in alternative transcript NM_001244710.1. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553389102; hg19: chr2-69573035;