# med.halowerk.com Gene Crosswalk

> med.halowerk.com Gene Crosswalk is a paid API for AI agents from med.halowerk.com, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-15).

Resolves a gene symbol or identifier and returns cross-referenced identifiers (Entrez, Ensembl), genomic location, biotype, description, and associated transcripts with protein products.

## Facts

- Endpoint: POST https://med.halowerk.com/v1/gene-crosswalk
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/med-halowerk-com-gene-crosswalk-e47f9ffc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LKm_vka1Mfr_NN4sJlpmb

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability med-halowerk-com-gene-crosswalk-e47f9ffc -d '<json body>'
```

Example prompt: Can you look up the gene BRCA2 and give me its Entrez and Ensembl identifiers, genomic location, biotype, and all its transcripts with protein products?

## When to prefer this

Use this endpoint when you need to cross-reference gene identifiers between NCBI (Entrez) and Ensembl databases in a single call, especially when you also need genomic coordinates, biotype, official description, and transcript-to-protein mappings. Prefer it over manual database lookups or separate API calls to NCBI and Ensembl when building bioinformatics pipelines, annotation tools, or research workflows that require normalized gene metadata.

## Known failure modes

- Unrecognized gene symbol returns an error or empty result
- Ambiguous identifier matching multiple genes may return unexpected results
- Gene identifiers not present in NCBI or Ensembl databases return no data
- Deprecated or retired gene symbols may fail to resolve
- Network or upstream database unavailability causes timeout

## How this service works

Resolves a gene symbol or identifier and returns the corresponding identifiers across NCBI and Ensembl: the gene with its Entrez and Ensembl identifiers, the genomic location with assembly, the biotype, the description, and the transcripts with their protein products.

## Output

Returns a structured record for the resolved gene including: Entrez gene ID, Ensembl gene ID, genomic location with assembly version, biotype (e.g. protein-coding, lncRNA), official gene description, and a list of transcripts each with their corresponding protein product identifiers.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string",
   "maxLength": 100,
   "minLength": 2,
   "description": "Gene symbol like TP53, an Ensembl id like ENSG00000141510, or an Entrez gene id."
  },
  "species": {
   "type": "string",
   "default": "homo_sapiens",
   "maxLength": 60,
   "description": "Ensembl species name. Required in practice — the same symbol exists in many species."
  },
  "include_transcripts": {
   "type": "boolean",
   "default": true
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/med-halowerk-com-gene-crosswalk-e47f9ffc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from med.halowerk.com](https://www.zero.xyz/host/med.halowerk.com/llms.txt)