# KIT D816V

Source: https://onco.cc/biomarkers/kit-d816v/  
OnCo record `kit-d816v` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

KIT D816V is the mutation behind almost every case of systemic mastocytosis. It makes the disease resistant to imatinib, and it is detected by a highly sensitive blood PCR; avapritinib treats the disease whether or not the mutation is confirmed.

## Summary

The exon 17 D816V substitution locks KIT in the active conformation and is present in over 90 percent of systemic mastocytosis, often at low allele burden requiring sensitive allele-specific PCR of blood or marrow. The FDA companion diagnostic list carries the ARUP KIT D816V Assay for imatinib in aggressive systemic mastocytosis (a humanitarian device exemption, H140006, 2015): imatinib is labelled for aggressive systemic mastocytosis without the D816V mutation or with unknown status, so the test selects patients by excluding D816V. Avapritinib's labels for advanced and indolent systemic mastocytosis do not require D816V testing; the mutation is also found in core-binding-factor AML and some GISTs where it confers imatinib resistance.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: KIT D816V; D816V; c-KIT D816V; KIT exon 17 mutation; KIT D816V mastocytosis
- Tags: biomarker; kit

## Sources

- AYVAKIT prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=645c887c-8cd4-4623-8da9-ac223d71a8b9
- FDA: List of FDA-Authorized Companion Diagnostic Devices: https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools

## Connected records

- biomarkers: [PDGFRA exon 18 mutation (D842V)](https://onco.cc/biomarkers/pdgfra-exon-18-d842v/)
- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Gastrointestinal stromal tumour (GIST)](https://onco.cc/cancers/gist/), [Systemic mastocytosis](https://onco.cc/cancers/systemic-mastocytosis/)
- drugs: [Avapritinib](https://onco.cc/drugs/avapritinib/), [Imatinib](https://onco.cc/drugs/imatinib/)
- terms: [On-target resistance mutations (gatekeeper, solvent-front, compound)](https://onco.cc/terms/gatekeeper-mutation/)
- targets: [KIT](https://onco.cc/targets/kit/)

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JSON: https://onco.cc/api/v1/entities/kit-d816v.json