The Craniofacial Phenotype of the Crouzon Mouse: Analysis of a Model for Syndromic Craniosynostosis Using Three-Dimensional MicroCT

2006 ◽  
Vol 43 (6) ◽  
pp. 740-747 ◽  
Author(s):  
Chad A. Perlyn ◽  
Valerie B. DeLeon ◽  
Christian Babbs ◽  
Daniel Govier ◽  
Lance Burell ◽  
...  
Keyword(s):  
Mouse Model ◽  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Distance Matrix ◽  
Mutant Mice ◽  
Matrix Analysis ◽  
Crouzon Syndrome ◽  
Wild Type ◽  
Skull Morphology ◽  
Euclidean Distance Matrix

Objective: To characterize the craniofacial phenotype of a mouse model for Crouzon syndrome by a quantitative analysis of skull morphology in mutant and wild-type mice and to compare the findings with skull features observed in humans with Crouzon syndrome. Methods: MicroCT scans and skeletal preparations were obtained on previously described Fgfr2C342Y/+ Crouzon mutant mice and wild-type mice at 6 weeks of age. Three-dimensional coordinate data from biologically relevant landmarks on the skulls were collected. Euclidean Distance Matrix Analysis was used to quantify and compare skull shapes using these landmark data. Results: Obliteration of bilateral coronal sutures was observed in 80% of skulls, and complete synostosis of the sagittal suture was observed in 70%. In contrast, fewer than 40% of lambdoid sutures were found to be fully fused. In each of the 10 Fgfr2C342Y/+ mutant mice analyzed, the presphenoid-basisphenoid synchondrosis was fused. Skull height and width were increased in mutant mice, whereas skull length was decreased. Interorbital distance was also increased in Fgfr2C342Y/+ mice as compared with wild-type littermates. Upper-jaw length was shorter in the Fgfr2C342Y/+ mutant skulls, as was mandibular length. Conclusion: Skulls of Fgfr2C342Y/+ mice differ from normal littermates in a comparable manner with differences between the skulls of humans with Crouzon syndrome and those of unaffected individuals. These findings were consistent across several regions of anatomic interest. Further investigation into the molecular mechanisms underlying the anomalies seen in the Crouzon mouse model is currently under way.

scholarly journals Fluctuating Asymmetry and Developmental Instability in Sagittal Craniosynostosis

2009 ◽  
Vol 46 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Valerie Burke DeLeon ◽  
Joan T. Richtsmeier
Keyword(s):  
Fluctuating Asymmetry ◽  
Three Dimensional ◽  
Distance Matrix ◽  
Developmental Instability ◽  
Matrix Analysis ◽  
Control Group ◽  
Euclidean Distance Matrix ◽  
Sagittal Craniosynostosis ◽  
Landmark Data ◽  
Cranial Shape

Objective: To determine whether premature sagittal craniosynostosis is associated with developmental instability in the skull by analyzing fluctuating asymmetry in skull shape. Design: Cranial shape was quantified by collecting coordinate data from landmarks located on three-dimensional reconstructions of preoperative computed tomography (CT) images of 22 children with sagittal craniosynostosis and 22 age-matched controls. A fluctuating asymmetry application of Euclidean distance matrix analysis (EDMA) was used to quantify and compare asymmetry in cranial shape using these landmark data. Results: In contrast to expectations, the sagittal craniosynostosis group did not show a statistically significant increase in the overall level of fluctuating asymmetry relative to the control group. However, we discerned statistically significant localized increases in fluctuating asymmetry in the sagittal craniosynostosis group at pterion and the anterior clinoid processes (α  =  .05). We also determined a significant correlation of fluctuating asymmetry values between the two groups (r  =  .71). Conclusions: We conclude that there is no evidence of a role for system-wide developmental instability in the etiology of nonsyndromic sagittal craniosynostosis. However, the localized evidence of asymmetry at the anterior clinoid processes in the sagittal synostosis group suggests an association with the tracts of dura mater that attach there.

The Effect of Neurocranial Surgery on Basicranial Morphology in Isolated Sagittal Craniosynostosis

2001 ◽  
Vol 38 (2) ◽  
pp. 134-146 ◽  
Author(s):  
Valerie Burke DeLeon ◽  
Michael P. Zumpano ◽  
Joan T. Richtsmeier
Keyword(s):  
Three Dimensional ◽  
Distance Matrix ◽  
Cranial Base ◽  
Growth Patterns ◽  
Matrix Analysis ◽  
Sagittal Synostosis ◽  
Euclidean Distance Matrix ◽  
Cross Sectional ◽  
Sagittal Craniosynostosis ◽  
Base Angle

Objective Isolated sagittal craniosynostosis produces a scaphocephalic neurocranium associated with abnormal basicranial morphology, providing additional evidence of the developmental relationship of the neurocranium and basicranium. Corrective surgical procedures vary, but the immediate impact of the surgical procedure is restricted to the neurocranium. This study addresses the secondary effects of neurocranial surgery on the cranial base. Design Three-dimensional (3-D) computed tomography (CT) scans were obtained for preoperative (n = 25) and postoperative (n = 12) patients with isolated sagittal synostosis. Landmark data from 14 landmarks on and around the cranial base were collected from 3-D CT reconstructions and analyzed using Euclidean distance matrix analysis. Subsamples of age-matched patients were used to identify basicranial differences in pre- and postoperative patients and to compare postoperative growth patterns identified in longitudinal data with preoperative growth patterns characterized in cross-sectional data. Results Statistically significant differences (p ≤ 0.10) were found in the morphology of the cranial base in preoperative and postoperative patients. The relative positions of the landmarks nasion, right asterion, and left asterion are similar in preoperative and postoperative patients. However, the position of these landmarks relative to the cranial base is different in the two groups, being positioned relatively more anteriorly in postoperative patients. In addition, we found that the cranial base angle, on average, neither increases nor decreases in the first postoperative year. These morphological differences are associated with divergent growth trajectories in the operated and unoperated cranial base. Conclusion Regardless of specific procedure, neurocranial surgery in sagittal synostosis patients affects growth patterns of the cranial base. The lack of change in the postoperative cranial base angle suggests that neurocranial surgery alleviates the occipital rotation and decreased cranial base angle described in the sagittal synostosis basicranium.

Methods for Studying Morphological Integration and Modularity

2010 ◽  
Vol 16 ◽  
pp. 213-243 ◽  
Author(s):  
Anjali Goswami ◽  
P. David Polly
Keyword(s):  
Distance Matrix ◽  
Japanese Macaques ◽  
Morphological Integration ◽  
Matrix Analysis ◽  
Euclidean Distance Matrix ◽  
Phenotypic Data ◽  
Graphical Modelling ◽  
Landmark Data ◽  
Competing Models ◽  
Matrix Correlation

Morphological integration and modularity are closely related concepts about how different traits of an organism are correlated. Integration is the overall pattern of intercorrelation; modularity is the partitioning of integration into evolutionarily or developmentally independent blocks of traits. Modularity and integration are usually studied using quantitative phenotypic data, which can be obtained either from extant or fossil organisms. Many methods are now available to study integration and modularity, all of which involve the analysis of patterns found in trait correlation or covariance matrices. We review matrix correlation, random skewers, fluctuating asymmetry, cluster analysis, Euclidean distance matrix analysis (EDMA), graphical modelling, two-block partial least squares, RV coefficients, and theoretical matrix modelling and discuss their similarities and differences. We also review different coefficients that are used to measure correlations. We apply all the methods to cranial landmark data from and ontogenetic series of Japanese macaques,Macaca fuscatato illustrate the methods and their individual strengths and weaknesses. We conclude that the exploratory approaches (cluster analyses of various sorts) were less informative and less consistent with one another than were the results of model testing or comparative approaches. Nevertheless, we found that competing models of modularity and integration are often similar enough that they are not statistically distinguishable; we expect, therefore, that several models will often be significantly correlated with observed data.

Comparison of Numeric Techniques in the Analysis of Cleft Palate Dental Arch Form Change

1997 ◽  
Vol 34 (4) ◽  
pp. 281-291 ◽  
Author(s):  
Mona E. McAlarney ◽  
Wei-Kwang Chiu
Keyword(s):  
Finite Element ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Distance Matrix ◽  
Matrix Analysis ◽  
Dental Arch ◽  
Scaling Analysis ◽  
Euclidean Distance Matrix ◽  
Arch Form ◽  
Form Change

Objective: Quantitative descriptions of form (size and shape) changes are significant to the understanding of the development, treatment planning, and prognosis of patients born with cleft lip and palate. This study compared the results of traditional dental arch form change measurements, such as width, depth, perimeter, and area, with four numeric methods: finite element scaling analysis, macroelement method, Euclidean distance matrix analysis, and conventional least-squares and resistant-fit theta rho Procrustes analyses. Design: Using tooth cusp landmarks on maxillary study casts, form change measurements of a male with complete bilateral cleft lip and palate at ages 2, 5, and 6 years were made comparing each age to the next older. Results and Conclusions: With the exception of the 2- to 5-year resistant-fit analysis, all numeric methods: 1) provide comparable results, 2) provide more detailed descriptions than do traditional methods, and 3) provide results that correlate well with the reported effects of increased lip pressure due to lip closure surgery. The use of finite-element scaling analysis on study casts is somewhat limited since: 1) there is more than one solution at teeth shared by many finite elements, 2) gross averaging of form change occurs within triangular elements, and 3) solutions can vary with the choice of element location. The use of the macroelement method circumvented the above finite element limitations with out compromising finite-element advantages. Procrustes results vary with the chosen superposition algorithm. The choice of the most appropriate Procrustes method required some a priori knowledge of form difference. The large number of results obtained by Euclidean distance matrix analysis and the nongraphic presentation of these results hamper quick interpretation but may be best suited for definitive statistical analysis. The graphic representation of both the magnitude and direction of: 1) landmark displacement in the Procrustes analyses (once size difference is eliminated), and 2) the rate of form change in the macroelement method provide an intuitive appreciation of how and where the casts differ.

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