One gene, many teeth: How C2CD3 shapes dental development — and evolution

One gene, many teeth: How C2CD3 shapes dental development — and evolution

A new study published in PNAS has identified the gene C2CD3 as a key regulator of tooth development in humans and animals alike. Researchers from King's College London and an international team linked rare variants in this gene to a broad spectrum of dental abnormalities in 24 patients — including missing teeth, extra teeth, unusual shapes, and teeth present at birth.

C2CD3 works by building primary cilia, tiny antenna-like structures on cells that help process developmental signals. When the gene is disrupted, it throws off a critical pathway called Sonic hedgehog (SHH) signaling — ramping it up in the upper jaw while dialing it down in the lower jaw. That position-dependent effect explains how one gene can produce seemingly opposite outcomes: extra teeth in some spots, missing teeth in others.

Key Takeaways:

• C2CD3 disruption in mice closely mirrored the dental abnormalities seen in human patients
• Chicken embryos carrying a C2CD3 variant grew tooth-like structures, suggesting birds retain dormant tooth-forming machinery
• The findings may help refine treatments for patients with complex dental conditions

Why it matters: This research doesn't just explain rare dental defects — it offers a window into how tooth development evolved across vertebrates, and why birds may have lost their teeth over the course of evolution.