Built for His Daughter: A Father’s Biotech Mission to Cure Rett Syndrome
Uncommon Therapeutics is a trailblazing biotech startup based in San Francisco, founded in 2024 by Noah Auerhahn and Ryan Lim. The company is on a mission to create multi-billion-dollar therapeutics for complex genetic diseases—starting with Rett Syndrome. What sets Uncommon apart is its deeply personal origin, its focus on disease-specific polytherapy strategies, and its novel approach to drug development that fuses biotech expertise with technology-driven innovation.
At its core, Uncommon Therapeutics challenges the traditional orthodoxy of biotech. Rather than betting on a single molecule or platform, it deploys an “uncommon” strategy: designing multiple therapeutics for each disease, leveraging the full spectrum of modern modalities—gene editing, ASOs, small molecules—and combining them based on deep biological insight and patient-centered urgency.
How Did a Personal Crisis Spark a Biotech Revolution?
The inception of Uncommon Therapeutics was born from a life-altering diagnosis. In 2021, co-founder Noah Auerhahn’s 18-month-old daughter was diagnosed with Rett Syndrome—a rare and devastating neurological disorder affecting 1 in 10,000 girls. Within months, she began losing the ability to walk, talk, and use her hands. The prognosis was bleak.
Noah, a successful tech entrepreneur, pivoted his entire life. He read over 300 scientific papers in nine months, built a Rolodex of leading researchers, and immersed himself in the world of drug development. But he didn’t stop at understanding—he took action.
By identifying a unique polytherapy cocktail of repurposed drugs not commonly prescribed for Rett, he was able to halt his daughter’s decline. Today, she is five years old, walking, smiling, learning to read, and ranked in the top 1% of individuals with Rett in terms of quality of life. This unprecedented progress proved to Noah that more could be done—not just for his daughter, but for thousands of others.
Why Is Now the Best Time to Build a Disease-Focused Biotech?
Biotech is undergoing a tectonic shift. For decades, drug development was the exclusive domain of a few well-funded institutions with proprietary platforms. Today, the rules have changed. Intellectual property around modalities such as CRISPR, mRNA, and ASOs is maturing or expiring. Mature Contract Research Organizations (CROs) exist for every stage of drug development. Expertise is widely available, and AI tools are drastically accelerating research timelines.
Unlike in other industries, where value accrues to platform builders, in biotech, the winners are increasingly the ones who create the drug assets themselves. Tools like machine learning, high-throughput screening, and gene editing no longer require in-house platforms—they can be accessed as services. The playing field has been leveled.
Uncommon Therapeutics is seizing this moment. It’s a biotech company born in the age of open-source tools, AI-driven discovery, and rapid iteration. With fewer barriers to entry and faster feedback cycles, small teams can do what once took entire institutions.
What Is Rett Syndrome and Why Start There?
Rett Syndrome is a rare genetic neurological disorder caused by mutations in the MECP2 gene. It primarily affects girls and leads to severe impairments in cognitive, motor, and verbal functions. Patients often face a cascade of symptoms including seizures, scoliosis, breathing abnormalities, and regression of previously acquired skills.
There is no known cure.
This complexity makes Rett a disease that defies the “one drug, one target” model of treatment. That’s why Uncommon’s polytherapy approach is so critical—it combines multiple therapeutics to tackle the layered biology of Rett from different angles simultaneously.
The company’s early success in improving one child’s quality of life validates the strategy and sets the stage for broader application.
Who Are the Founders Behind Uncommon Therapeutics?
Uncommon’s founders bring a potent combination of personal motivation and deep domain expertise.
Noah Auerhahn, Co-Founder and CEO, is a serial tech entrepreneur. He sold his first company to Rakuten for $15 million and raised over $75 million for his second. But his daughter’s diagnosis shifted his focus entirely. He committed over $1 million of personal funds to build an early-stage therapeutic pipeline for Rett and is deeply involved in the company’s scientific and strategic direction.
Ryan Lim, PhD, Co-Founder and CSO, is a seasoned biomedical scientist and biotech entrepreneur with over a decade of experience in neurodegenerative diseases. At Uncommon, he leads efforts in gene editing, antisense oligonucleotides, and small-molecule development. Previously, at Modulo Bio, he spearheaded AI-driven drug discovery and advanced a therapeutic candidate through IND-enabling studies.
Together, Noah and Ryan form a two-person powerhouse, poised to build what could be the first billion-dollar biotech company with just two employees.
How Does Uncommon Therapeutics Develop Its Drugs?
Uncommon Therapeutics follows a radically efficient drug development model.
With an initial investment of just $1 million, the team used the best available CROs, tools, and advisory networks to design three novel therapeutic candidates for Rett Syndrome. All three are now showing efficacy in patient-derived cell lines—a major milestone that typically takes larger companies years and tens of millions of dollars to achieve.
Their approach includes:
- Repurposing Approved Drugs: Fastest path to patients with safety profiles already established.
- ASO (Antisense Oligonucleotides): Targeting the root cause at the RNA level for gene-specific intervention.
- Gene Editing (e.g., CRISPR): For long-term, potentially curative effects.
- AI-Driven Drug Discovery: Accelerating screening and optimization by orders of magnitude.
This multi-pronged pipeline not only increases the likelihood of clinical success but also builds defensible IP across multiple therapeutic categories.
What’s Next for Uncommon Therapeutics?
Uncommon is now preparing for the next major leap: in vivo validation and early-stage clinical development. With promising results in patient cells, the company is focused on translating these into treatments that can be administered safely and effectively in humans.
The path to the clinic includes:
- Toxicology studies
- Pharmacokinetics and pharmacodynamics
- Preclinical animal studies
- IND (Investigational New Drug) submission
Given the urgency and founder-driven nature of the mission, timelines are aggressive—but grounded in scientific rigor.
The company is also exploring expansion into other genetic diseases using the same polytherapy approach, building multiple high-value therapeutics per disease, not just per company.
Why Could This Be One of the Most Important Biotech Companies of the Decade?
Uncommon Therapeutics isn’t just building drugs. It’s building a new playbook for biotech.
In an industry often plagued by bureaucracy, slow timelines, and risk aversion, Uncommon operates with speed, conviction, and a founder’s sense of urgency. The company blends the hacker mindset of Silicon Valley with the precision of modern molecular biology.
And it’s working. Already, Uncommon has achieved more progress with fewer resources than most early-stage biotech startups. If their therapeutics make it through clinical validation, the financial and human impact could be immense, not just for Rett Syndrome, but for countless other diseases that require equally nimble, personalized, and multi-modal approaches.