A splicing mutation in VPS4B causes dentin dysplasia I

Area of Science:

• Genetics
• Developmental Biology
• Molecular Biology

Background:

• Dentin Dysplasia I (DDI) is an autosomal-dominant disorder.
• It is characterized by abnormal tooth development, including rootless teeth and altered pulp morphology.
• The genetic basis of DDI is complex and heterogeneous.

Purpose of the Study:

• To identify the genetic cause of Dentin Dysplasia I in a large Chinese family.
• To investigate the role of the identified gene in tooth formation and the Wnt/β-catenin signaling pathway.

Main Methods:

• Genome-wide linkage analysis was performed on a family with DDI.
• Mutation screening of candidate genes within the linked region was conducted.
• Functional studies including transcript analysis, protein structure prediction, and zebrafish model experiments were utilized.

Main Results:

• A novel splice site mutation (IVS7+46C>G) in the VPS4B gene was identified and co-segregated with DDI in the family.
• The mutation led to aberrant VPS4B transcripts, altered protein structure, reduced protein expression, and impaired subcellular localization, indicating a loss of function.
• VPS4B was found to regulate odontogenesis via the Wnt/β-catenin signaling pathway, and its depletion in zebrafish mimicked DDI phenotypes.

Conclusions:

• VPS4B is identified as a novel disease-causing gene for Dentin Dysplasia I.
• The study elucidates the critical role of VPS4B in tooth formation through the Wnt/β-catenin signaling pathway.