CTSK
Chr 1ARcathepsin K
Also known as: CTS02, CTSO, CTSO1, CTSO2, PKND, PYCD
Cathepsin K is a lysosomal cysteine protease that degrades extracellular matrix and mediates osteoclastic bone resorption. Mutations cause pycnodysostosis, an autosomal recessive skeletal dysplasia characterized by osteosclerosis, short stature, and increased bone fragility. The gene shows very low constraint against loss-of-function variants (pLI 0.00003), which is consistent with the recessive inheritance pattern.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
CTSK · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
External Resources
Links to major genomics databases and tools