---
title: "HGVS Variant Converter (c. <-> g. <-> p.)"
method: POST
path: "/hgvs_convert"
tags: ["Alignment & variants"]
---

# HGVS Variant Converter (c. <-> g. <-> p.)

`POST /hgvs_convert`

## Request

- Base URL: `https://seqbench.com/api/v1`
- URL: `https://seqbench.com/api/v1/hgvs_convert`
- Auth: none required

Parse an HGVS "c." variant description (by gene symbol, RefSeq NM_, or Ensembl ENST accession), convert it to genomic (g.) coordinates via a real, live-fetched Ensembl exon/CDS map (transcripts resolved through the bundled MANE RefSeq<->Ensembl crosswalk), apply 3'-rule normalization to any del/dup/ins, and predict the protein (p.) effect where that is safely computable. Also accepts a genomic "g." position on a chromosome or RefSeqGene (NC_/NG_, GRCh38 or GRCh37): it is validated and placed on GRCh38 by NCBI, projected onto the MANE Select transcript by Ensembl, and converted back by this tool's own engine, which must agree — so the answer rests on two independent conversions. And the "NC_/NG_(NM_…):c." form converts on the transcript in parentheses. A "c." on a RefSeq transcript outside MANE is placed by NCBI and converted on the gene's MANE Select transcript. A single amino-acid substitution ("TP53:p.Pro72Arg") is read as its codon change when exactly one single-base change produces it; otherwise every candidate is listed. Refuses cleanly — rather than guessing — for circular/mitochondrial genomes, RNA-level input, other protein-level input, uncertain/mosaic syntax, and splice-junction-adjacent or inversion protein effects.

## Request body

- object
  - `variant` string, required: A full HGVS description: a "c." on a gene symbol or transcript ("NM_000546.6:c.215C>G", "TP53:c.215C>G"), a "g." position on a chromosome or RefSeqGene ("NC_000017.11:g.7676154G>C", "NG_017013.2:g.16397C>G"), a "c." with its transcript in parentheses ("NC_000017.11(NM_000546.6):c.215C>G"), or a single amino-acid substitution ("TP53:p.Pro72Arg", "TP53:p.P72R"). Substitution (">"), deletion ("del"), duplication ("dup"), insertion ("ins"), delins, and inversion ("inv") are supported.

## Response `200`

Tool ran successfully.

- SuccessResponse: Standard success envelope returned by every single-tool call.
  - `ok` unknown, required
  - `tool` string, required: The tool slug that ran.
  - `result` object, required: Tool-specific output object. Its shape depends on the tool — call `GET /{tool}` or see the docs for each tool's fields.
  - `gate` GateResult
    - `pass` boolean, required: True if and only if every hard check passed.
    - `checks` GateCheck[], required
      - `id` string, required
      - `label` string, required
      - `severity` 'hard' | 'soft', required
      - `pass` boolean, required
      - `message` string, required
      - `value` number
      - `threshold` string
    - `notChecked` string[], required: Honest list of what this gate does NOT verify.
  - `provenance` Provenance, required
    - `apiVersion` string, required
    - `tool` union, required: Tool slug, or an array of slugs (one per step) for a workflow.
      - string
      - string[]
    - `generatedAt` string, date-time, required: ISO 8601 timestamp of when the result was generated.

## Other responses

- `400`: Invalid argument or the tool could not run.
- `404`: Unknown tool.
- `429`: Rate limited (metered tools only). Body carries code `rate_limited` and retryable `true`; honor the Retry-After header.
- `503`: A metered tool is momentarily at capacity. The identical request should succeed after Retry-After; body carries code `upstream_unavailable`.

---

[API](https://skmtc.dev/seqbench/apis/seqbench-api.md) · [All operations](https://skmtc.dev/seqbench/apis/seqbench-api/llms.txt) · [OpenAPI document](https://skmtc.dev/seqbench/apis/seqbench-api/revisions/132575216865?raw)