Correction: The effect of sex and age on facial shape directional asymmetry in adults: A 3D landmarks-based method study.

[This corrects the article DOI: 10.1371/journal.pone.0288702.].

Classification performance of the Sella-Tunis et al. (2017) sex estimation method in Czech population: different posterior probability threshold approaches.

In this study we tested classification performance of a sex estimation method from the mandible originally developed by Sella-Tunis et al. (2017) on a heterogeneous Israeli population. Mandibular linear dimensions were measured on 60 CT scans derived from the Czech living population. Classification performance of Israeli discriminant functions (DFs-IL) was analyzed in comparison with calculated Czech discriminant functions (DFs-CZ) while different posterior probability thresholds (currently discussed in the forensic literature) were employed. Our results comprehensively illustrate sensitivity of different discriminant functions to population differences in body size and degree of sexual dimorphism. We demonstrate that the error rate may be biased when presented per posterior probability threshold. DF-IL 1 showed least sensitivity to population origin and fulfilled criteria of sufficient classification performance when applied on the Czech sample with a minimum posterior probability threshold of 0.88 reaching overall accuracy ≥ 95%, zero sex bias, and 80% of classified individuals. The last parameter was higher in DF-CZ 1 which was the main difference between those two DFs suggesting relatively low dependance on population origin. As the use of population-specific methods is often prevented by complicated assessment of population origin, DF-IL 1 is a candidate for a sufficiently robust method that could be reliably applied outside the reference sample, and thus, its classification performance deserves further testing on more population samples.

The influence of biological relatedness on sexual dimorphism and sex classification based on external morphology of the frontal bone.

The most significant sexual differences in the human skull are located in the upper third of the face (the frontal bone), which is a useful research object, mainly in combination with virtual anthropology methods. However, the influence of biological relatedness on sexual dimorphism and frontal bone variability remains unknown. This study was directed at sexual difference description and sex classification using the form and shape of the external surface of the frontal bones from a genealogically documented Central European osteological sample (nineteenth to twentieth centuries). The study sample consisted of 47 cranial CT images of the adult members of several branches of one family group over 4 generations. Three-dimensional virtual models of the frontal bones were analyzed using geometric morphometrics and multidimensional statistics. Almost the entire external frontal surface was significantly different between males and females, especially in form. Significant differences were also found between this related sample and an unrelated one. Sex estimation of the biologically related individuals was performed using the classification models developed on a sample of unrelated individuals from the recent Czech population (Cechová et al. in Int J Legal Med 133: 1285 1294, 2019), with a result of 74.46% and 63.83% in form and shape, respectively. Failure of this classifier was caused by the existence of typical traits found in the biologically related sample different from the usual manifestation of sexual dimorphism. This can be explained as due to the increased degree of similarity and the reduction of variability in biologically related individuals. The results show the importance of testing previously published methods on genealogical data.

How reliable is the application of the sex classifier based on exocranial surface (Musilová et al., 2016) for geographically and temporally distant skull series.

Sex estimation is one of the crucial trends in cases of findings of unknown skeletal remains in forensics and bioarchaeology. The changing nature of sexual dimorphism (population specificity, secular trend, other external and internal factors influence) brings challenges to developing new methods; and there are new aims to be independent of these changes such, as the method by Musilová et al. (2016). These methods need to be evaluated on different datasets to determine if they are truly reliable among populations from different places and times, in the case of bioarchaeology. This study assessed the application of the aforementioned method on non-European contemporary and ancient populations to identify the reliability of the method on this separate dataset. The study sample consisted of 96 CT scans of skulls from contemporary Egyptians and 54 3D models of skulls from the Egyptian Old Kingdom Period (2700-2180 BC). The classifier method, previously tested on both Czech and French populations, yielded high accuracies (over 90 %) for sex estimation. For the contemporary Egyptian skull sample, the classifier was able to determine males versus females with an 89.59 % accuracy rate and an AUC value (area under the curve - a measure of the combined specificity and sensitivity of the test) of 0.99; this proves that the classifier is reliable even with a lower degree of accuracy. Conversely, the Old Kingdom Period sample yielded a lower level of accuracy at around 70 % (61.11 %, precisely), although with an AUC value of 0.92, the result is not considered reliable.

The effect of sex and age on facial shape directional asymmetry in adults: A 3D landmarks-based method study.

OBJECTIVES: Facial directional asymmetry research, including age-related changes, is crucial for the evaluation of treatment of craniofacial malformations/trauma in orthodontics, facial surgery and forensic sciences. The aim was to describe facial directional asymmetry (DA) in different age categories of adults using 3D methods. According to our hypothesis, facial shape DA (1) depends on sex; (2) differs among age groups; and (3) has wider variability in older age. MATERIAL AND METHODS: A cross-sectional sample of healthy Czech adults without craniofacial trauma or anomalies consisted of 300 3D facial models (151 females). The age-range in the study was between 20-80 years. The shape asymmetry of 28 3D landmarks was evaluated using geometric morphometrics and multivariate statistics. RESULTS: The manifestation of DA was similar in both sexes and in each age category; however, there were some statistical differences. In contrast to the ideal symmetrical face, the mean asymmetrical faces tended to create a slightly bent "C" shape of the midline. Therefore, the upper face was rotated slightly clockwise and the lower face counter-clockwise. The right eye was located slightly higher, with the nasal tip and mandibular region tilting to the left. Sex differences in facial DA were significant before the age of 40. DA was more significant in the youngest males than in the oldest, while the women's DA did not change. CONCLUSIONS: The DA patterns were similar in both sexes and in all age categories (a slightly bent C shape of the midline); however, some significant local differences between male age groups were found. A significantly more pronounced asymmetry compared to other age groups was found only in the youngest males from 20 to 40 years. Moreover, significant sexual dimorphism of DA rapidly decreased after middle age, likely caused by the same age-related changes of the face during aging.

Morphometric Assessment of Facial Morphology in Infants with Orofacial Clefts up to two Years of Age: A Three-Dimensional Cross-Sectional Study.

OBJECTIVE: To assess modelled facial development of infants with unilateral cleft lip (CL) and cleft lip and palate (UCLP) compared to controls up to two years of age. DESIGN AND PARTICIPANTS: A total of 209 facial images of children (CL: n = 37; UCLP: n = 39; controls: n = 137) were obtained in four age categories (T0 = 0.2-0.5; T1 = 0.6-1.0; T2 = 1.1-1.5; T3 = 1.6-2.0 years) and were evaluated using stereophotogrammetry and geometric morphometry. All patients underwent lip surgery before T0, patients with UCLP underwent palatoplasty (T0, T1 before palatoplasty; T2, T3 after palatoplasty). RESULTS: In patients with CL, the forehead was significantly retracted (p ≤ 0.001), while the supraorbital and ocular regions were prominent (p ≤ 0.001). The oronasal region appeared convex (p ≤ 0.001). The lower lip and chin were non-significantly protruded. In patients with UCLP, a significantly retracted forehead and prominent supraorbital region were apparent (p ≤ 0.001). A retrusive oronasal region (p ≤ 0.001) was observed in the middle face. The chin was anteriorly protruded (p ≤ 0.01). No progression of deviations was found with increasing age. After the first year, a slight improvement in the morphological features became apparent. The shape variability of the clefts and controls overlapped, suggesting a comparable modelled facial development. CONCLUSIONS: The facial morphology of individuals with cleft was comparable to the norm. Shape deviation was apparent in the oronasal region, forehead, and chin, which minimised with increasing age even in complete clefts.

Palatal surface development from 6 years of age to early adulthood: data modelling using 3D geometric morphometrics.

OBJECTIVES: The study followed the modelling of postnatal growth of a healthy palate of the Central European (Czech) population sample based on transverse data on sex and age from 6 to 19 years. MATERIALS AND METHODS: Digitised 3D models of 212 healthy palatal surfaces were evaluated using 3D geometric morphometrics and superimpositions. The individuals were grouped based on age (preschool, younger and older school age, younger and older adolescents, young adults) and sex (♂ n = 101, ♀ n = 111). RESULTS: Female palatal development was non-linear and was interrupted between the 10-12 years and then proceeded intensively until the age of 15 when it ceased. In contrast, male-modelled growth was consistent throughout the follow-up and continued linearly until at least 19 years of age. The palate did not widen further with increasing age, and primarily palatal vaulting and heightening were found. The characteristics and distribution of areas with extensive modelled growth changes were comparable in females and males, as confirmed by the location of principal components (PC1 and PC2) within modal space and growth trajectories. The extent of sexual dimorphism increased from 15 years of age due to pubertal spurt combined with earlier completion of palatal development in females. CONCLUSIONS: The study showed modelled healthy palatal development from 6 years of age to early adulthood, which might be utilised as reference standards for the Central European population sample. CLINICAL RELEVANCE: The comparison of normal reference subjects with patients with cranio-maxillo-facial dysmorphologies represents the first step in diagnosing and establishing effective therapy.

Three-dimensional analysis of modeled facial aging and sexual dimorphism from juvenile to elderly age.

A detailed understanding of craniofacial ontogenetic development is important in a variety of scientific disciplines dealing with facial reconstruction, forensic identification, ageing prediction, and monitoring of pathological growth, including the effect of therapy. The main goals of this study were (1) the construction of the facial aging model using local polynomial regression fitting separately for both sexes, (2) evaluation of the aging effect not only on facial form as a whole but also on dimensions important for clinical practice, and (3) monitoring of the development of shape facial sexual dimorphism. Our study was based on the form and shape analysis of three-dimensional facial surface models of 456 individuals aged 14-83 years. The facial models were obtained using a structured light-based optical scanner and divided (for some analyses) into four age categories (juveniles, young adults, middle adults, and elderly adults). The methodology was based on geometric and classic morphometrics including multivariate statistics. Aging in both sexes shared common traits such as more pronounced facial roundness reducing facial convexity, sagging soft tissue, smaller visible areas of the eyes, greater nose, and thinner lips. In contrast to female faces, male faces increase in size until almost 30 years of age. After the age of 70, male facial size not only stagnates, like in females, but actually decreases slightly. Sexual dimorphic traits tended to diminish in the frontal and orbitonasal areas and increase in the gonial area.

Kinship and the familial occurrence of skeletal developmental anomalies in the noble Swéerts-Sporck family (Bohemia, 17th to 20th centuries).

OBJECTIVE: To determine the degree of similarity of biologically related individuals according to the occurrence of skeletal developmental anomalies (SDA), to see whether these anomalies reflect documented biological relationships. MATERIAL AND METHODS: The sample consists of the skeletal remains of seven members of the noble Swéerts-Sporck family from the 17th-20th centuries. Eighty-nine SDA were examined using morphological assessment, X-ray and CT. The degree of similarity was calculated using a similarity coefficient (Cvrcek et al., 2018). RESULTS: There were three shared SDA in the sample (cranial shift at the C-T border, cervical ribs, hypoplasia of rib 12), and another fifteen individual SDA were reported. The degree of similarity between individuals supports their documented relationships. The greatest similarity was found in closely related individuals such as father/son or siblings, and the least between unrelated individuals. CONCLUSIONS: SDA can be used as a supportive tool for detecting family relationships. The results correspond to the conclusions of earlier analyses of non-metric traits and frontal sinuses in the same sample: the smaller the biological distance between individuals, the greater the degree of their similarity. SIGNIFICANCE: Using unique human skeletal collections, this communication contributes to the expansion of knowledge about the familial occurrence of SDA. LIMITATIONS: The small number of individuals limits the use of statistical approaches. SUGGESTIONS FOR FURTHER RESEARCH: The results call for research on this topic using a larger sample with known genealogical data and the same approaches, to confirm our conclusions.

Familial occurrence of skeletal developmental anomalies as a reflection of biological relationships in a genealogically documented Central European sample (19th to 20th centuries).

Skeletal developmental anomalies (SDA) are a subject of constant interest across scientific disciplines, but still mostly as isolates and curiosities. The aim of this study was to find out to what extent the occurrence of SDA reflects documented biological relationships. The skeletal remains of 34 individuals with known genealogical data were available, members of one family over four generations (19th to 20th centuries, Bohemia, Czech Republic), including some inbred individuals. The occurrence of 89 SDA was assessed on the basis of scopic morphological evaluation and X-ray and CT examinations. The degree of similarity between individuals was calculated using a "similarity coefficient" (SC). A linear model was used to test the relationship between positive values of the SC and the relatedness of biologically related individuals. Simultaneously, based on population frequencies of the evaluated anomalies, those that could be considered familial were recorded. A statistically significant relationship between morphological similarity and the biological distance between individuals was found. The greatest similarity was found among close relatives such as parents and children, siblings, or grandparents and grandchildren. The effect of increased consanguinity on the occurrence of anomalies was not confirmed, however. Seventeen SDA shared by closely related individuals were found in the sample, supporting the documented family relationships among them. Eleven of these were selected as possibly familial, but only five were statistically significant: an elongated styloid process, a cervical block vertebrae (arch, facet joints), hamate hamulus aplasia, anteater nose sign, and incomplete fusion of the S1 spinous process. There were also 28 cases of individual occurrences of 17 different SDA, without connection to the documented relationships between individuals.

Age-related differences in cranial sexual dimorphism in contemporary Europe.

Biomechanical load and hormonal levels tended to change just like the soft and skeletal tissue of the elderly with age. Although aging in both sexes shared common traits, it was assumed that there would be a reduction of sexual dimorphism in aged individuals. The main goals of this study were (1) to evaluate age-related differences in cranial sexual dimorphism during senescence, (2) to determine age-related differences in female and male skulls separately, and (3) to compare skull senescence in Czech and French adult samples as discussed by Musilová et al. (Forensic Sci Int 269:70-77, 2016). The cranial surface was analyzed using coherent point drift-dense correspondence analysis. The study sample consisted of 245 CT scans of heads from recent Czech (83 males and 59 females) and French (52 males and 51 females) individuals. Virtual scans in the age range from 18 to 92 years were analyzed using geometric morphometrics. The cranial form was significantly greater in males in all age categories. After size normalization, sexual dimorphism of the frontal, occipital, and zygomatic regions tended to diminish in the elderly. Its development during aging was caused by morphological changes in both female and male skulls but secular changes must also be taken into account. The most notable aging changes were the widening of the neurocranium and the retrusion of the face, including the forehead, especially after the age of 60 in both sexes. Sexual dimorphism was similar between the Czech and French samples but its age-related differences were partially different because of the population specificity. Cranial senescence was found to degrade the accuracy of sex classification (92-94%) in the range of 2-3%.

Palatal growth changes in newborns with unilateral and bilateral cleft lip and palate from birth until 12 months after early neonatal cheiloplasty using morphometric assessment.

OBJECTIVES: To compare palatal growth changes in infants with complete unilateral (UCLP) or bilateral (BCLP) cleft lip and palate during the first year of life. MATERIALS AND METHODS: Upper dental arches of 68 neonates with UCLP and BCLP were evaluated using 2D and 3D morphometry based on dental casts obtained in two age categories (T0 before early neonatal cheiloplasty-UCLP 4 ± 3 days, BCLP 6 ± 5 days; T1 before palatoplasty-UCLP 10 ± 2 months, BCLP 12 ± 3 months). RESULTS: Intensive palatal growth was manifested in both directions of the palate. Palatal growth in the anterior direction was not restricted, despite the intercanine (CC´) and anterior (LL´) widths being significantly narrowed in the BCLP group (CC´ p = 0.019, LL´ p = 0.009). The posterior dental arches were significantly enlarged (UCLP p ≤ 0.001; BCLP p ≤ 0.001). The negative effect of cleft severity on palatal length was not confirmed (p = 0.802). Variability of the palate was immense mainly in BCLP infants (T0); however, it decreased in both cleft types, confirming the formative effect of palatal growth leading to alveolar cleft closure (UCLP p ≤ 0.001; BCLP p = 0.006 on the right, 0.005 on the left). CONCLUSIONS: Both analyzed cleft groups (UCLP, BCLP) grew favorably during the first year of life, and the palatal growth was not limited in any direction. CLINICAL RELEVANCE: Geometric morphometry allowed a comprehensive analysis of the palate, which can contribute to the improvement of surgical methods.

Three-dimensional mixed longitudinal study of facial growth changes and variability of facial form in preschool children using stereophotogrammetry.

OBJECTIVES: Since the normal, non-pathological facial growth in preschool children is not sufficiently reported, the aim was to follow growth changes of facial surface, sex differences and facial variability in preschool children using 3D stereophotogrammetry. SETTINGS AND SAMPLE POPULATION: Mixed longitudinal sample of healthy Caucasian preschool children without head and facial trauma or craniofacial anomalies from 3.4 to 6.7 years of age consisted of 25 girls and 17 boys. MATERIALS AND METHODS: 136 3D facial models from optical scanner Vectra 3D were evaluated by geometric morphometrics (CPC-DCA, PCA, per-vertex t test). RESULTS: In both sexes, the lower face was widened and elongated, and the prominences of the superciliary arches, lower orbital region, nose, lips and chin increased. Facial surface increments were more even in girls with a maximum between the fourth and fifth year of age, while in boys, there was the most intensive growth between fifth and sixth year of age. Sexual dimorphism was very stable during investigated period, only less statistically significant at the age of 3 years. Boys had more prominent lateral lower part of forehead, nose and lips than girls in every age category. CONCLUSIONS: The longitudinal growth of the face between third and sixth year of age was similar in both sexes, facial sex differences were found in terms of intensity, size and timing. Variability of facial form showed that boys' faces were larger on average and facial shape did not differ. The knowledge of facial growth is essential for diagnostics and clinical practice.

A test of the Bulut et al. (2016) landmark-free method of quantifying sex differences in frontal bone roundness in a contemporary Czech sample.

The skull, along with the pelvic bone, serves an important source of clues as to the sex of human skeletal remains. The frontal bone is one of the most significant sexually dimorphic structures employed in anthropological research, especially when studied by methods of virtual anthropology. For this reason, many new methods have been developed, but their utility for other populations remains to be verified. In the present study, we tested one such approach-the landmark-free method of Bulut et al. (2016) for quantifying sexually dimorphic differences in the shape of the frontal bone, developed using a sample of the Turkish population. Our study builds upon this methodology and tests its utility for the Czech population. We evaluated the shape of the male and female frontal bone using 3D morphometrics, comparing virtual models of frontal bones and corresponding software-generated spheres. To do so, we calculated the relative size of the frontal bone area deviating from the fitted sphere by less than 1 mm and used these data to estimate the sex of individuals. Using our sample of the Czech population, the method estimated the sex correctly in 72.8% of individuals. This success rate is about 5% lower than that achieved with the Turkish sample. This method is therefore not very suitable for estimating the sex of Czech individuals, especially considering the significantly greater success rates of other approaches.

Three-dimensional development of the palate in bilateral orofacial cleft newborns 1 year after early neonatal cheiloplasty: Classic and geometric morphometric evaluation.

OBJECTIVES: The aim of this study was to assess palatal growth in newborns with complete bilateral cleft lip and palate (cBCLP) and bilateral cleft lip and palate with tissue bridges (BCLP + B) 1 year after early neonatal cheiloplasty (ENC). MATERIAL AND METHODS: The methodology was based on classic and morphometric analysis of dental models of newborns with cBCLP or BCLP + B. These analyses included metric analysis, coherent point drift-dense correspondence analysis, superprojection methods, and multivariate statistics. Dental casts were observed in two age categories, which were compared with each other. The first cast was obtained from each patient before ENC (T0, 5 ± 5 days) and the second one prior to palatoplasty (T1, 12 ± 6 months). RESULTS: Fifty-two dental models obtained from 26 newborns with cBCLP and BCLP + B were evaluated. The results showed that over the 12-month period, alveolar clefts were narrowed in both cleft types due to anterior growth combined with the formative effect of suturing. This was confirmed by decreases in the dimensions of the right (T0 9.93 ± 2.80 mm, T1 6.64 ± 2.43 mm; p ≤ 0.003) and left (T0 10.71 ± 4.13 mm, T1 6.69 ± 4.29 mm; p ≤ 0.003) alveolar clefts in cBCLP patients. Similar reductions in alveolar cleft widths occurred on the left side (T0 11.69 ± 4.75 mm, T1 4.34 ± 2.97 mm; p ≤ 0.001) of BCLP + B patients, while on the right side, which was connected by a combined tissue bridge, there was non-significant narrowing of the alveolar cleft (T0 1.61 ± 1.34 mm, T1 1.04 ± 0.70 mm; p = 0.120). The ENC did not restrict posterior palatal growth, meaning that intertuberosity width was extended in cBCLP (T0 32.80 ± 3.15 mm, T1 35.86 ± 2.80 mm; p ≤ 0.001) and in BCLP + B neonates (T0 34.01 ± 2.15 mm, T1 36.21 ± 2.14 mm; p ≤ 0.004). Width and length measurements in the observed groups showed growth tendencies equivalent to those in noncleft or LOP patients. Palatal variability was greater in neonatal cBCLP, but was reduced during the monitored period, approximating that for BCLP + B. Regions with the most notable palatal growth were located primarily at the premaxilla and at the anterior and partially posterior ends of the maxillary segments. CONCLUSION: Early neonatal cheiloplasty had no negative effect on palatal growth in any direction. There was no reduction in the length or width of the palate during the first year of life, nor was there narrowing of the dentoalveolar arch. The formative effect of the operated lip on the anterior part of the palate was confirmed. This, in combination with the favorable growth, lead to closure of the alveolar cleft.

Sex estimation using external morphology of the frontal bone and frontal sinuses in a contemporary Czech population.

Sex estimation is a task of utmost importance in forensic anthropology and bioarcheology. Along with the pelvic bone, the skull is the most important source of sexual dimorphism. On the human skull, the upper third of the face (i.e., the frontal bone) is one of the most significant sexually dimorphic structures useful in anthropological research, especially when studied by methods of virtual anthropology. This study was focused on sex estimation using the form and shape of the external surface of the frontal bone with or without the inclusion of its sinuses. The study sample consisted of 103 cranial CT images from a contemporary Czech population. Three-dimensional virtual models of the frontal bones and sinuses were analyzed using geometric morphometrics and multidimensional statistics: coherent point drift-dense correspondence analysis (CPD-DCA), principal component analysis (PCA), and support vector machine (SVM). The whole external frontal surface was significantly different between males and females both in form and shape. The greatest total success rate of sex estimation based on form was 93.2%, which decreased to 86.41% after crossvalidation, and this model identified females and males with the same accuracy. The best estimation based on shape reached a success rate of 91.26%, with slightly greater accuracy for females. After crossvalidation, however, the success rate decreased to 83.49%. The differences between sexes were significant also in the volume and surface of the frontal sinuses, but the sex estimation had only 64.07% accuracy after crossvalidation. Simultaneous use of the shape of the frontal surface and the frontal sinuses improved the total success rate to 98.05%, which decreased to 84.46% after crossvalidation.

Sex and ancestry related differences between two Central European populations determined using exocranial meshes.

Assessing sex and population affinity is an important part of the process of biologically identifying unknown human remains, and the skull is usually one of the best structures for assessing both these components of the biological profile. Population affinity is known to be a hugely important variable when estimating sex because the manifestation of sexually dimorphic traits, body size or social and behavioural habits differs across populations. Therefore, for forensic purposes, the estimation of ancestry is a necessary step in the identification of bone remains. The present study improves on the results of a previously developed virtual method using the exocranial surface for sex estimation and assessing population affinity. The ability to assess these components of the biological profile was successfully tested on 208 individuals from two recent European populations. The original classifier was based on geometric morphometric analyses (CPD-DCA, PCA, SVM) and was able to assess the sex of individuals belonging to one French population with an accuracy exceeding 90 % Musilová et al. [1]. To improve the reliability of the method, the Czech population sample was added to the dataset, yielding the highest accuracy of 96.2 %; using the combined dataset, the reliability of the method was 91.8 %. Secondly, we used the same method utilizing inter-population differences to classify individuals based on the shape of the skull. The greatest accuracy rate was 92.8 %, which makes our method a promising tool for sex estimation and assessing population affinity.

Simulation of facial growth based on longitudinal data: Age progression and age regression between 7 and 17 years of age using 3D surface data.

Modelling of the development of facial morphology during childhood and adolescence is highly useful in forensic and biomedical practice. However, most studies in this area fail to capture the essence of the face as a three-dimensional structure. The main aims of our present study were (1) to construct ageing trajectories for the female and male face between 7 and 17 years of age and (2) to propose a three-dimensional age progression (age -regression) system focused on real growth-related facial changes. Our approach was based on an assessment of a total of 522 three-dimensional (3D) facial scans of Czech children (39 boys, 48 girls) that were longitudinally studied between the ages of 7 to 12 and 12 to 17 years. Facial surface scans were obtained using a Vectra-3D scanner and evaluated using geometric morphometric methods (CPD-DCA, PCA, Hotelling's T2 tests). We observed very similar growth rates between 7 and 10 years in both sexes, followed by an increase in growth velocity in both sexes, with maxima between 11 and 12 years in girls and 11 to 13 years in boys, which are connected with the different timing of the onset of puberty. Based on these partly different ageing trajectories for girls and boys, we simulated the effects of age progression (age regression) on facial scans. In girls, the mean error was 1.81 mm at 12 years and 1.7 mm at 17 years. In boys, the prediction system was slightly less successful: 2.0 mm at 12 years and 1.94 mm at 17 years. The areas with the greatest deviations between predicted and real facial morphology were not important for facial recognition. Changes of body mass index percentiles in children throughout the observation period had no significant influence on the accuracy of the age progression models for both sexes.

Modeling age-specific facial development in Williams-Beuren-, Noonan-, and 22q11.2 deletion syndromes in cohorts of Czech patients aged 3-18 years: A cross-sectional three-dimensional geometric morphometry analysis of their facial gestalt.

Three-dimensional (3D) virtual facial models facilitate genotype-phenotype correlations and diagnostics in clinical dysmorphology. Within cross-sectional analysis of both genders we evaluated facial features in representative cohorts of Czech patients with Williams-Beuren-(WBS; 12 cases), Noonan-(NS; 14), and 22q11.2 deletion syndromes (22q11.2DS; 20) and compared their age-related developmental trajectories to 21 age, sex and ethnically matched controls in 3-18 years of age. Using geometric morphometry statistically significant differences in facial morphology were found in all cases compared to controls. The dysmorphic features observed in WBS were specific and manifested in majority of cases. During ontogenesis, dysmorphic features associated with increased facial convexity become more pronounced whereas other typical features remained relatively stable. Dysmorphic features observed in NS cases were mostly apparent during childhood and gradually diminished with age. Facial development had a similar progress as in controls, while there has been increased growth of patients' nose and chin in adulthood. Facial characteristics observed in 22q11.2DS, except for hypoplastic alae nasi, did not correspond with the standard description of its facial phenotype because of marked facial heterogeneity of this clinical entity. Because of the sensitivity of 3D facial morphometry we were able to reach statistical significance even in smaller retrospective patient cohorts, which proves its clinical utility within the routine setting.

Kinship and morphological similarity in the skeletal remains of individuals with known genealogical data (Bohemia, 19th to 20th centuries): A new methodological approach.

OBJECTIVES: This article proposes a new approach, called the "similarity coefficient" (SC) for verifying family relationships from skeletal remains using nonmetric traits. Based on this method and further analyses, the authors aim to show the degree of similarity between individuals with varying degrees of kinship, including inbred individuals. MATERIALS AND METHODS: Our sample includes the skeletal remains of 34 individuals with known genealogical data (four generations, 19th to 20th centuries). A total of 243 skeletal nonmetric traits were evaluated with respect to their anatomical characteristics. The SC was calculated by quantifying the agreement of trait occurrence between individuals. We also identified the traits that support the biological relationships of particular individuals by accounting for their population frequencies. RESULTS: There was a positive correlation between the morphological similarity of biologically related individuals and their biological distance. In some cases, we found greater degree of morphological similarity between first cousins than among other close relatives such as parents and children. At the same time, there was no statistically significant difference in the degree of similarity between inbred individuals and common relatives. Proven family relationships were best reflected by cranial traits, especially bone bridges associated with the courses of blood vessels and nerves. CONCLUSIONS: The use of skeletal nonmetric traits for the detection of relatives is possible. There is a relationship between biological distance and the degree of morphological similarity in related individuals. It also appears that inbreeding, despite previous assumptions, does not lead to a significant reduction in morphological variation.