Advancing genotype-phenotype analysis through 3D facial morphometry: insights from Cri-du-Chat syndrome

Area of Science:

• Genetics
• Medical Imaging
• Anthropology

Background:

• Facial dysmorphism is a key indicator in numerous monogenic disorders, posing diagnostic challenges.
• Accurate assessment of complex facial shape variations in syndromes is crucial for clinical practice.

Purpose of the Study:

• To introduce and validate three-dimensional (3D) morphometric methods for analyzing facial dysmorphism.
• To utilize Cri-du-Chat syndrome (CdCS) as a model for demonstrating the utility of 3D facial analysis.

Main Methods:

• Analysis of 3D facial images from 24 CdCS participants, 4540 controls, and 5 individuals with 5p15.33-15.32 deletions.
• Application of age- and sex-correction methods to account for normal facial variation.
• Quantification of phenotypic variation and exploration of genotype-phenotype correlations in CdCS.

Main Results:

• Identified age-related changes in CdCS facial features.
• Demonstrated consistent directional differences in facial shape between CdCS patients and controls.
• Delineated critical regions for facial dysmorphism on chromosome 5p by distinguishing CdCS from 5p15.33-15.32 deletion phenotypes.

Conclusions:

• 3D facial morphometry offers a valuable complement to standard clinical assessments of facial dysmorphism.
• The study provides insights into the genetic underpinnings of facial shape in CdCS.
• 3D morphometric techniques show significant potential for improving clinical diagnostics, variant interpretation, and syndrome classification.