KRT13

Chr 17AD

keratin 13

Also known as: CK13, K13, WSN2

NCBI Gene: 3860 ENSG00000171401 UniProt: P13646

The protein encoded by this gene is a member of the keratin gene family. The keratins are intermediate filament proteins responsible for the structural integrity of epithelial cells and are subdivided into cytokeratins and hair keratins. Most of the type I cytokeratins consist of acidic proteins which are arranged in pairs of heterotypic keratin chains. This type I cytokeratin is paired with keratin 4 and expressed in the suprabasal layers of non-cornified stratified epithelia. Mutations in this gene and keratin 4 have been associated with the autosomal dominant disorder White Sponge Nevus. The type I cytokeratins are clustered in a region of chromosome 17q21.2. Alternative splicing of this gene results in multiple transcript variants; however, not all variants have been described. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

White sponge nevus 2MIM #615785

Active trials

Pathogenic / LP

145

ClinVar variants

Pubs (1 yr)

-0.5

Missense Z

0.84

LOEUF

Clinical Summary— KRT13

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Population Constraint (gnomAD)

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

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ClinVar Variants

8 Pathogenic / Likely Pathogenic· 73 VUS of 145 total submissions

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.

0.84LOEUF

pLI 0.001

Z-score 2.06

OE 0.46 (0.27–0.84)

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.

-0.52Z-score

OE missense 1.09 (0.99–1.20)

303 obs / 278.7 exp

Tolerant

Tolerant to missense variation

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.0.46 (0.27–0.84)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.1.09 (0.99–1.20)

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.1.11

0≤1.21.6

LoF obs/exp: 8 / 17.2Missense obs/exp: 303 / 278.7Syn Z: -0.94

0.95top 5%

GOF

0.94top 5%

LOF

0.1598th %ile

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

DNprediction above median

GOFprediction 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.