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Updated: May 21, 2026

Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
Published on: August 22, 2022
Craniofacial variations in the tricho-dento-osseous syndrome
T Nguyen1, C Phillips, S Frazier-Bower
1Department of Orthodontics, University of North Carolina, Chapel Hill, NC 27599–7450, USA. nguyent@dentistry.unc.edu
Tricho-dento-osseous (TDO) syndrome, linked to the DLX3 gene, causes distinct hair, teeth, and bone issues. TDO-affected individuals exhibit a Class III skeletal pattern and specific mandibular and ramus variations compared to unaffected family members.
Area of Science:
- Genetics
- Craniofacial Biology
- Dental Anthropology
Background:
- Tricho-dento-osseous (TDO) syndrome is an autosomal dominant disorder.
- It presents with characteristic hair, dental, and bone anomalies.
- The genetic basis involves a DLX3 gene deletion, but craniofacial variations require further characterization.
Purpose of the Study:
- To compare craniofacial variations in TDO-affected individuals versus unaffected family members.
- To provide detailed phenotypic characterization of TDO syndrome.
- To clarify the craniofacial classification within TDO syndrome.
Main Methods:
- Cephalometric analysis of 53 TDO-affected subjects and 34 controls.
- Digitization of standardized cephalograms.
- Statistical analysis using a general linear model with family as a random effect.
Main Results:
- Significant craniofacial variability observed in both groups.
- TDO-affected subjects displayed a Class III skeletal pattern (reduced SNA and ANB angles).
- Longer mandibular corpus length (GoGn) and shorter ramus height were noted in TDO-affected individuals (p < 0.05).
Conclusions:
- TDO syndrome is associated with specific craniofacial morphological differences.
- Cephalometric analysis reveals a Class III tendency and distinct mandibular dimensions in affected individuals.
- Further research can refine TDO classification based on these craniofacial findings.
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