GCNT2

Chr 6

glucosaminyl (N-acetyl) transferase 2 (I blood group)

Also known as: CCAT, CTRCT13, GCNT2C, GCNT5, IGNT, II, NACGT1, NAGCT1

NCBI Gene: 2651ENSG00000111846UniProt: Q8N0V5

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]

ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtCataract 13, with adult i phenotype

Clinical highlights

Interpreting a novel variant
Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.
0
Active trials
17
Pubs (1 yr)
—
P/LP submissions
—
P/LP missense
1.16
LOEUF
LOF
Mechanism· G2P
Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?
1.16LOEUF
pLI 0.000
Z-score 1.14
OE 0.67 (0.40–1.16)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?
-1.10Z-score
OE missense 1.21 (1.09–1.34)
262 obs / 216.5 exp
Tolerant

Tolerant to missense variation

Observed / Expected Ratios?
LoF OE?0.67 (0.40–1.16)
0≤0.351.4
Missense OE?1.21 (1.09–1.34)
0≤0.61.4
Synonymous OE?1.17
0≤1.21.6
LoF obs/exp: 9 / 13.5Missense obs/exp: 262 / 216.5Syn Z: -1.28

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

GCNT2 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients