# NTHL1-associated polyposis

Source: https://onco.cc/terms/nthl1-associated-polyposis/  
OnCo record `nthl1-associated-polyposis` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

NTHL1-associated polyposis is a rare inherited condition in which a person has two faulty copies of the NTHL1 gene and develops many bowel polyps, bowel cancer and, in women, womb cancer. Care is planned at a specialist centre because there are too few patients for a fixed schedule.

## Summary

Autosomal recessive. Weren 2015 (Nature Genetics) found a homozygous NTHL1 nonsense variant, a base-excision repair gene, in seven people from three families with adenomatous polyposis; each family progressed to colorectal cancer in at least one member, all three affected women had an endometrial malignancy or premalignancy, and the tumours were not hypermutated but enriched for cytosine-to-thymine transitions. NTHL1 is one of the multiple-adenoma genes beyond APC and MUTYH, with GREM1, POLE, POLD1 and MSH3.

BSG 2020 found insufficient data for specific guidance and recommends referral to a multidisciplinary expert centre.

## Fields

- Kind: Term
- Last checked: 2026-11-04
- Also known as: NTHL1 polyposis; NTHL1-related polyposis
- Tags: gap-fill; hereditary

## Notes

- Orphanet ORPHA:454840. In the NHS directory it is tested under R211, inherited polyposis.

## Sources

- Weren, Nat Genet 2015: a germline homozygous NTHL1 mutation causes adenomatous polyposis and colorectal cancer: https://doi.org/10.1038/ng.3287
- Monahan, Gut 2020: BSG, ACPGBI and UKCGG guidelines for the management of hereditary colorectal cancer: https://doi.org/10.1136/gutjnl-2019-319915
- Orphanet ORPHA:454840: https://www.orpha.net/en/disease/detail/454840

## Connected records

- terms: [Colonoscopy](https://onco.cc/terms/colonoscopy/), [Hereditary cancer syndromes](https://onco.cc/terms/hereditary-cancer-syndromes/), [MUTYH-associated polyposis](https://onco.cc/terms/mutyh-associated-polyposis/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Endometrial cancer](https://onco.cc/cancers/endometrial/)
- technologies: [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/)
- targets: [NTHL1](https://onco.cc/targets/nthl1/)
- drugs: [Quest Comprehensive Hereditary Cancer Panel (66 genes)](https://onco.cc/drugs/quest-hereditary-cancer-panel/)

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