Genetic Variant NM_001491.3:c.577T>G (chr6-10557000-T-G) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_001491.3(GCNT2):c.577T>G(p.Phe193Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,472 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 (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

GCNT2
NM_001491.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 6.08

Variant links:

Genes affected

GCNT2 (HGNC:4204): (glucosaminyl (N-acetyl) transferase 2 (I blood group)) This gene encodes the enzyme responsible for formation of the blood group I antigen. The i and I antigens are distinguished by linear and branched poly-N-acetyllactosaminoglycans, respectively. The encoded protein is the I-branching enzyme, a beta-1,6-N-acetylglucosaminyltransferase responsible for the conversion of fetal i antigen to adult I antigen in erythrocytes during embryonic development. Mutations in this gene have been associated with adult i blood group phenotype. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq, Jul 2008]

GCNT2 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.978

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCNT2	NM_001491.3 link	c.577T>G	p.Phe193Val	missense_variant	Exon 1 of 3	ENST00000316170.9	NP_001482.1	Q8N0V5-2
GCNT2	NM_145649.5 link	c.925+27164T>G		intron_variant	Intron 3 of 4	ENST00000495262.7	NP_663624.1	Q8N0V5-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCNT2	ENST00000316170.9 link	c.577T>G	p.Phe193Val	missense_variant	Exon 1 of 3	1	NM_001491.3	ENSP00000314844.3		Q8N0V5-2
GCNT2	ENST00000495262.7 link	c.925+27164T>G		intron_variant	Intron 3 of 4	2	NM_145649.5	ENSP00000419411.2		Q8N0V5-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000399

AC:

AN:

250756

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135498

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000882

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461472

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727044

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Cataract 13 with adult I phenotype

Uncertain:1

Feb 25, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a GCNT2-related disease. This sequence change replaces phenylalanine with valine at codon 193 of the GCNT2 protein (p.Phe193Val). The phenylalanine residue is highly conserved and there is a small physicochemical difference between phenylalanine and valine. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.22

BayesDel_noAF

Uncertain

0.080

CADD

Benign

DANN

Uncertain

0.99

Eigen

Pathogenic

0.84

Eigen_PC

Pathogenic

0.75

FATHMM_MKL

Uncertain

0.93

M_CAP

Benign

0.022

MetaRNN

Pathogenic

0.98

D;D

MetaSVM

Benign

-0.95

PROVEAN

Pathogenic

-6.9

D;.

REVEL

Uncertain

0.52

Sift4G

Pathogenic

0.0010

D;.

Vest4

0.79

MutPred

0.93

Loss of ubiquitination at K196 (P = 0.0877);Loss of ubiquitination at K196 (P = 0.0877);

MVP

0.60

ClinPred

0.99

GERP RS

5.0

Splicing

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over