Overlapping DSPP mutations cause dentin dysplasia and dentinogenesis imperfecta.

Area of Science:

• Genetics
• Oral Biology
• Molecular Medicine

Background:

• Dentinogenesis imperfecta (DGI) and dentin dysplasia (DD) are rare genetic disorders affecting dentin formation.
• These conditions are typically caused by mutations in the dentin sialophosphoprotein (DSPP) gene and often exhibit distinct phenotypes within families.
• Previous research suggested a correlation between the location of DSPP frameshift mutations and the resulting phenotype, with mutations in the early repeat domain linked to DD and 3' mutations to DGI.

Purpose of the Study:

• To investigate a family presenting with dentin dysplasia (DD) and a novel DSPP mutation.
• To determine if DSPP mutations can result in variable phenotypes (DGI or DD) within families.
• To explore the potential role of genetic modifiers in DSPP-related disorders.

Main Methods:

• Genetic analysis of a family with dentin dysplasia.
• Identification and characterization of a novel frameshift mutation in the DSPP gene (c.3141delC).
• Comparison of mutation location and associated phenotype with previously reported cases.

Main Results:

• A novel 1-base pair deletion frameshift mutation (c.3141delC) in the DSPP gene was identified in a family with dentin dysplasia (DD).
• This mutation is located within the DSPP repeat domain, an area previously associated exclusively with the DGI phenotype.
• The findings demonstrate that mutations in the same region of the DSPP gene can lead to either DGI or DD.

Conclusions:

• Overlapping DSPP mutations can result in either dentinogenesis imperfecta or dentin dysplasia phenotypes.
• The specific phenotype (DGI or DD) associated with certain DSPP mutations may be influenced by genetic modifiers.
• Further research is needed to identify the genetic modifier(s) closely linked to DSPP that influence disease presentation.