Genetic research links KDF1 mutation to impaired dental epithelial organization

Dental enamel is the hardest substance in the human body, protecting teeth from wear, temperature changes, and decay. However, enamel cannot regenerate once damaged. Inherited disorders, such as amelogenesis imperfecta, disrupt enamel formation during development, leaving affected individuals with fragile, discolored, and decay-prone teeth. Although several genes have been linked to this condition, the mechanisms by which specific mutations impair enamel-forming cells have remained unclear.

Addressing this challenge, a research team was led by Professor Wei Zhao and Professor Dongsheng Yu from the Department of Oral Emergency, Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology at Sun Yat-sen University, Guangzhou, China. The researchers investigated a patient-derived keratinocyte differentiation factor 1 (KDF1) mutation, p.R303P, previously associated with inherited enamel defects.

Using genetically engineered mice, molecular analyses, imaging techniques, and dental epithelial cell experiments, they explored how the mutation disrupts tooth development. Their findings were published in Volume 18 of the journal International Journal of Oral Science on May 21, 2026.

The team first examined KDF1 activity during tooth development. They found that KDF1 was highly expressed in dental epithelial cells and was closely associated with regions of cell-cell contact, suggesting a role in maintaining epithelial organization. Although the mutation did not reduce KDF1 production, it impaired proper membrane localization, suggesting disruption of cellular interactions essential for enamel formation.

To assess the effects of the mutation, the researchers studied mice carrying one or two mutant copies of KDF1. Both groups developed enamel abnormalities, with the most severe defects observed in homozygous animals. Analyses revealed thinner enamel, reduced mineral density, abnormal enamel prism structure, and delayed tooth eruption. Mutant mice also showed lower levels of key enamel proteins and enzymes, including amelogenin, ameloblastin, and matrix metalloproteinase 20, which are necessary for enamel secretion and maturation.

Further experiments showed that the mutation disrupted adhesive structures that connect ameloblasts, the cells responsible for enamel production. Levels of important adhesion molecules, including E-cadherin and integrin β4, were significantly reduced. As adhesion weakened, Hippo pathway regulation became disrupted, allowing excessive accumulation of YAP in the nucleus. This activated genes that promote cell proliferation. Rather than maturing into enamel-producing cells, mutant ameloblasts remained in a proliferative state and failed to differentiate properly.

Our findings reveal that KDF1 is much more than a structural protein. It acts as a critical coordinator that links cell adhesion to signaling pathways controlling whether ameloblasts continue dividing or mature to form enamel. When this balance is lost, enamel development is severely compromised."

Wei Zhao, Professor, Department of Oral Emergency, Guanghua School of Stomatology, Hospital of Stomatology

The researchers next tested whether correcting this signaling imbalance could improve enamel development. Using verteporfin, a drug that inhibits YAP-TEAD1 interactions, they partially reversed the abnormal cellular behavior. Treated cells showed reduced proliferation and improved differentiation, while mutant mice displayed increased enamel volume. Although enamel mineralization was not completely restored, the findings demonstrated that the disease process can be modified therapeutically.

"This work provides a strong foundation for developing targeted treatments for hereditary enamel disorders," said Prof. Yu. "By identifying a drug-responsive pathway, we have opened new opportunities for translating fundamental developmental biology into future clinical interventions."

The implications extend beyond dentistry. Because cell adhesion and Hippo-YAP signaling regulate tissue growth in many organs, the findings may stimulate collaborations in regenerative medicine, stem cell biology, tissue engineering, craniofacial research, and precision medicine. In the short term, the study improves understanding of the genetic basis of enamel disorders and may support earlier diagnosis. Over the longer term, these insights could contribute to therapies that preserve, repair, or regenerate dental tissues, improving oral health outcomes for future generations.

Overall, the study uncovers a previously unknown mechanism linking a disease-causing KDF1 mutation to enamel defects through disrupted cell adhesion and Hippo-YAP signaling. By showing that pharmacological intervention can partially rescue these abnormalities, the researchers provide new insight into tooth development and a promising path toward future treatments for inherited enamel disorders.