GALNT12

Chr 9

polypeptide N-acetylgalactosaminyltransferase 12

Also known as: CRCS1, GalNAc-T12

NCBI Gene: 79695 ENSG00000119514 UniProt: Q8IXK2

This gene encodes a member of a family of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases, which catalyze the transfer of N-acetylgalactosamine (GalNAc) from UDP-GalNAc to a serine or threonine residue on a polypeptide acceptor in the initial step of O-linked protein glycosylation. Mutations in this gene are associated with an increased susceptibility to colorectal cancer.[provided by RefSeq, Mar 2011]

Primary Disease Associations & Inheritance

{Colorectal cancer, susceptibility to, 1}MIM #608812

UniProtColorectal cancer 1

Active trials

Pathogenic / LP

ClinVar variants

Pubs (1 yr)

0.1

Missense Z

0.94

LOEUF

Clinical Summary— GALNT12

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Gene-Disease Validity (ClinGen)

colorectal cancer, susceptibility to, 1 · ADLimited

Limited evidence — not for standalone diagnostic reporting

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.

0.94LOEUF

pLI 0.000

Z-score 1.77

OE 0.59 (0.39–0.94)

Tolerant

Typical tolerance to LoF variation

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.

0.13Z-score

OE missense 0.98 (0.89–1.08)

272 obs / 278.2 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.

LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.59 (0.39–0.94)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.98 (0.89–1.08)

0≤0.61.4

Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.98

0≤1.21.6

LoF obs/exp: 13 / 22.0Missense obs/exp: 272 / 278.2Syn Z: 0.14

0.6649th %ile

GOF

0.6930th %ile

LOF

0.2581th %ile

This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

GOFprediction above median

DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.