Genetic Variant GCNT2:c.-26A>G (chr6-10528886-A-G) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_145649.5(GCNT2):c.-26A>G variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000013 in 1,540,258 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 7.2e-7 ( 0 hom. )

Consequence

GCNT2
NM_145649.5 5_prime_UTR

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.0690

Publications

5 publications found

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 Gene-Disease associations (from GenCC):

cataract 13 with adult I phenotype
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
total early-onset cataract
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

GCNT2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.81).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_145649.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GCNT2	NM_145649.5	MANE Select	c.-26A>G		5_prime_UTR	Exon 3 of 5	NP_663624.1	Q8N0V5-1
	GCNT2	NM_001374747.1		c.-26A>G		5_prime_UTR	Exon 1 of 3	NP_001361676.1	Q8N0V5-1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
GCNT2	ENST00000495262.7	TSL:2 MANE Select	c.-26A>G	5_prime_UTR	Exon 3 of 5	ENSP00000419411.2	Q8N0V5-1
GCNT2	ENST00000379597.7	TSL:1	c.-26A>G	5_prime_UTR	Exon 1 of 3	ENSP00000368917.3	Q8N0V5-1
GCNT2	ENST00000410107.5	TSL:1	c.67+19728A>G	intron	N/A	ENSP00000386321.1	B7ZBL3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152148

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

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

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251022

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.0000617

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

7.20e-7

AC:

AN:

1387992

Hom.:

Cov.:

AF XY:

0.00000144

AC XY:

AN XY:

695004

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32056

American (AMR)

AF:

0.00

AC:

AN:

44638

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25672

East Asian (EAS)

AF:

0.00

AC:

AN:

39324

South Asian (SAS)

AF:

0.00

AC:

AN:

84794

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53192

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5124

European-Non Finnish (NFE)

AF:

9.57e-7

AC:

AN:

1045230

Other (OTH)

AF:

0.00

AC:

AN:

57962

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152266

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74450

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000241

AC:

AN:

41556

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2114

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

112

Bravo

AF:

0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.81

CADD

Benign

4.3

(source)

DANN

Benign

0.49

PhyloP100

0.069

Splicing

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over