About Key Proteo
Key Proteo is a Seattle diagnostics company that builds proteomic tests to screen newborns for rare, treatable genetic disorders. Its Immuno-SRM platform measures proteins that are present in very small amounts. The first four targets are Wilson disease, Wiskott Aldrich syndrome, X-linked agammaglobulinemia and adenosine deaminase (ADA) deficiency. It plans to serve public health, reference and hospital laboratories. In March 2024 it was pursuing FDA De Novo classification of a test kit for those four disorders.
Dr. Sihoun Hahn, a physician, laboratorian and academic researcher, co-founded the company in 2019. He is chief executive officer and chairman of the board. Jae-Hoon Song, MD, PhD, is a board member. The company received CLIA certification in April 2025, which lets its laboratory perform diagnostic testing on human specimens. It announced it would offer diagnostic testing for the same four diseases. In March 2024 it announced plans for a 5,000-square-foot Seattle facility with a CLIA laboratory, corporate headquarters and research space.
Funding Rounds (SEC Form D)
| First sale | Filed with SEC | Amount sold | Investors | Avg. check | Terms | Filing |
|---|---|---|---|---|---|---|
| Mar 25, 2026 | Oct 23, 2026 | $2,330,000of $2.5M target | 3 | $776K | EquityRule 506(b) | Form D ↗ |
| May 4, 2023 | May 19, 2023 | $3,028,381of $5.0M target | 3 | $1.0M | EquityRule 506(b) | Form D ↗ |
| Total, two offerings | $5,358,381 | |||||
First sale is the date the first investor in the offering committed to invest. Companies must file Form D within 15 days of that date, so filing dates run later.
Rounds announced by Key Proteo
What the company said publicly about its funding. Announced amounts can differ from Form D figures: an announcement can combine several closings, and some money is raised without a Form D.
| Announced | Round | Amount | Investors | Source |
|---|---|---|---|---|
| Aug 23, 2023 | Series A | $5 million | BRV Capital Management, Ignite Innovations and Mint Venture Partners (co-leads) | Key Proteo press release ↗ |
Why Investors Backed Key Proteo
Key Proteo is a Seattle company that builds proteomic tests to screen newborns for rare genetic disorders that can be treated. Dr. Sihoun Hahn, a physician with more than 30 years of experience, co-founded it in 2019. A $5 million Series A in 2023 was meant to speed its path to FDA clearance. It has since earned CLIA certification and had Wilson disease abstracts accepted at EASL 2026.
The problem it targets
Key Proteo's case is that many people with treatable genetic disorders may have no symptoms until later childhood or early adulthood. Left undiagnosed, these disorders can have irreversible or fatal outcomes. Sources Key Proteo cites put the average time to diagnose a rare disease at four to five years. They also put the average economic burden at $266,000 per patient per year. Early screening aims to spare families that diagnostic odyssey before symptoms start.
What the product does
The Immuno-SRM platform is patent pending. Key Proteo's claim is that it has shown faster turnaround and lower costs than next-generation sequencing. The assay in its first paper is a multiplexed LC-MS/MS proteomic test for Wilson disease and inherited immune disorders. Key Proteo also plans services for biopharma and research groups that run clinical research supporting gene therapy development. The website carries a "for research use only" label.
Progress so far
The pilot behind that first paper used over 30,000 Washington State samples. The journal accepted the paper in January 2025. In May 2026, EASL 2026 accepted abstracts on Key Proteo's ATP7B peptide testing. The abstracts report high sensitivity for Wilson disease in groups where it is common. In Gran Canary Island, the validated AUC was 0.94. Sardinia data are pending because the sample size is limited. Key Proteo is also the peptide analysis partner for a Spanish National Grant study of about 150 Wilson disease patients and controls. It has signed memoranda of understanding with Eton Pharmaceutical and Thermo-Fisher.
Who backs it
BRV Capital Management, Ignite Innovations and Mint Venture Partners led the $5 million Series A announced on August 23, 2023. The money was meant to speed FDA clearance for the first four disorders on the test menu. At that time, Key Proteo was running a large pilot study to validate the platform. It was also collaborating with the Washington State Department of Health's newborn screening program.
We wrote this summary from public statements by Key Proteo and its investors. It is not investment advice.
Key Proteo in the News
Leadership Team
Executive officers and directors listed on Key Proteo's Form D filed Oct 23, 2026.
Earlier filings also listed William Parr (director, last listed May 2023).
Sources
- SECKey Proteo, Inc. filing history
- CompanyKey Proteo: About Us
- CompanyKey Proteo: News & Events
- CompanyKey Proteo: EASL 2026 abstracts and Spanish grant study
- CompanyKey Proteo: CLIA certification
- CompanyKey Proteo: first manuscript accepted
- CompanyKey Proteo: clinical laboratory expansion plans
- PressPR Newswire: clinical laboratory expansion plans