Craniofacial Growth in Apert Syndrome as Measured by Finite-Element Scaling Analysis

Richtsmeier, Joan T.

doi:10.1159/000146614

Cited by 28 publications

(12 citation statements)

References 5 publications

(6 reference statements)

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“…Accordingly, Kohn et al (1993) showed that annular deformations of the cranial vault produce significant effects on the morphology of the cranial base and face. Similar conclusions arise from experimental vault deformation in mice (Pucciarelli 1978), and studies of premature closure of cranial sutures (Babler et al 1987), and craniosynostoses (Moss 1959;Kreiborg 1981;Richtsmeier 1987Richtsmeier , 1988Richtsmeier , 2002. Even when these previous studies focused on absolute morphological differences rather than on covariances among traits, their results are useful to evaluate and compare the degree of localization of the effect of biomechanical different ACD types.…”

Section: Developmental Constraintsmentioning

confidence: 60%

Developmental and Genetic Constraints on Neurocranial Globularity: Insights from Analyses of Deformed Skulls and Quantitative Genetics

et al. 2009

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Neurocranial globularity is one of the few derived traits defining anatomically modern humans. Variations in this trait derive from multiple and complex interactions between portions of the brain and the size and shape of the cranial base, among other factors. Given their evolutionary and functional importance, neurocranial globularity is expected to present high genetic and developmental constraints on their phenotypic expression. Here we applied two independent approaches to investigate both types of constraints. First, we assessed if patterns of morphological integration are conserved or else disrupted on a series of artificially deformed skulls in comparison to nondeformed (ND) ones. Second, after the estimation of the genetic covariance matrix for human skull shape, we explored how neurocranial globularity would respond to putative selective events disrupting the normal morphological patterns. Simulations on these deviations were explicitly set to replicate the artificial deformation patterns in order to compare developmental and genetic constraints under the same biomechanical conditions. In general terms, our results indicate that putative developmental constraints help to preserve some aspects of normal morphological integration even in the deformed skulls. Moreover, we find that the response to selection in neurocranial globularity is pervasive. In other words, induced changes in the vault generate a global response, indicating that departures from normal patterns of neurocranial globularity are genetically constrained. In summary, our combined results suggest that neurocranial globularity behaves as a highly genetic and developmental constrained trait.

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Section: Developmental Constraintsmentioning

confidence: 60%

Developmental and Genetic Constraints on Neurocranial Globularity: Insights from Analyses of Deformed Skulls and Quantitative Genetics

et al. 2009

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“…The data are examined lon-within each sample: normal, Crouzon, and gitudinally in alternate studies (Richtsmeier, Apert. One by one, within each age class, the ,1987Richtsmeier and Cheverud, 1986). age-specific standard (normal mean) is deReaders interested in the composition of the formed into each of the normal individuals three samples by individual and age group which combine to make the mean.…”

Section: Datamentioning

confidence: 99%

“…The mode of statistical analysis applied here is a single example of the possible ways in which to test hypotheses about morphological differences between groups of forms. Alternate quantities and methods have been used to summarize form change calculated by finite element and other related methods (Moss et al, 1985(Moss et al, , 1987Cheverud and Richtsmeier, 1986;Richtsmeier and Cheverud, 1986;Lavelle, 1985;Grayson et al, 1985;Richtsmeier, 1987). Experience will determine the values and methods which are most appropriate to specific research problems.…”

Section: No Deformationmentioning

confidence: 99%

“…The finite element scaling (FES) method, based on a composite of principles developed in finite element analysis and continuum mechanics, has recently been applied to the study of variation in biological forms (Niklas, 1977;Lew and Lewis, 1977;Lewis et al, 1980;Cheverud et al, 1983;Patel, 1983;Moss et al, 1985Moss et al, , 1987Richtsmeier, 1985Richtsmeier, , 1987Cheverud and Richtsmeier, 1986;Richtsmeier and Cheverud, 1986;Lozanoff and Diewart, 1986). By using this registration-free method, observer invariant quantities are obtained which measure localized morphological change without reference to any fixed, arbitrary center.…”

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confidence: 99%

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Comparative study of normal, Crouzon, and Apert craniofacial morphology using finite element scaling analysis

Richtsmeier

1987

American J Phys Anthropol

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Finite element scaling analysis is used to study differences in morphology between the craniofacial complex of normal individuals and those affected with the syndromes of Apert and Crouzon. Finite element scaling quantifies the differences in shape and size between forms without reference to any fixed, arbitrary registration point or orientation line and measures the amount of form change required to deform one object into another. Two-dimensional coordinates of landmarks digitized from annual sets of cephalometric radiographs were used in the analysis. A simple tabulation shows no difference in variances between the normal and pathological samples. A test of mean differences depicts the Apert and Crouzon morphologies as significantly different from normal. The Apert palate differs from normal in shape in the older age groups analyzed, and palatal size differences are most common at the posterior nasal spine. The Apert pituitary fossa and basi-occiput are significantly larger than normal. The Crouzon pituitary fossa is also larger than normal, but the difference is not always significant. The typical morphology of the Crouzon nose is due more to differences in shape than size. The Crouzon basi-occiput is significantly smaller than normal. An age association of the differences between the normal and pathological craniofacies was found in Apert syndrome but not in Crouzon syndrome. Apert syndrome is characterized by a more homogeneous pattern of craniofacial dysmorphology from 6 months to 18 years of age than Crouzon syndrome.

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“…Whether or not a specific pattern of malgrowth is the process responsible for this age progressivity in dysmorphology has not been sufficiently determined (but see Kreiborg, 1986;Richtsmeier, 1988).…”

Section: Example 2: Dysmorphology In Apert Syndromementioning

confidence: 99%

On comparing biological shapes: Detection of influential landmarks

Lele

Richtsmeier

1992

American J Phys Anthropol

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For problems of classification and comparison in biological research, the primary focus is on the similarity of forms. A biological form consists of size and shape. Several approaches for comparing biological forms using landmark data are available. If the two biological forms are demonstrated to be different, the next important issue is to localize the differences by identifying those areas which differ most between the two objects. In this paper we suggest a technique to detect influential landmarks, those which contribute most to the difference between forms. We study the effectiveness of the technique using three-dimensional simulated data sets and two examples. Results suggest that the technique is useful in the study of biological form and its variation.

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Craniofacial Growth in Apert Syndrome as Measured by Finite-Element Scaling Analysis

Cited by 28 publications

References 5 publications

Developmental and Genetic Constraints on Neurocranial Globularity: Insights from Analyses of Deformed Skulls and Quantitative Genetics

Developmental and Genetic Constraints on Neurocranial Globularity: Insights from Analyses of Deformed Skulls and Quantitative Genetics

Comparative study of normal, Crouzon, and Apert craniofacial morphology using finite element scaling analysis

On comparing biological shapes: Detection of influential landmarks

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