Journal of craniofacial genetics and developmental biology最新文献

The purpose of this study was to describe the location and morphology of notochordal remnants in the cranial base in normal and pathological conditions and to relate these findings to the morphological appearance of the sella turcica. Serially cut sagittal sections of paraffin-embedded sella turcica tissue blocks from 88 normal and pathological fetuses, 13 to 24 weeks of gestation, were examined. Twenty-seven specimens out of 88 had visible notochordal remnants in the cranial base, and these constituted the material available for this study. A straight notochordal course is always seen in normal sella turcica morphology, and a non-straight notochordal course is always seen in malformed sella turcica. Among the fetuses diagnosed at autopsy as "normal fetuses," both normal and pathological findings in the sella turcica regions were observed. The pathological findings were always found in the spontaneously aborted fetuses (five cases). Among the fetuses diagnosed at autopsy as "pathological fetuses," both normal and pathological findings were also observed in the sella region. Our conclusion is that the morphological appearance of the notochordal remnants in the dorsum sellae is associated with the morphology of the sella turcica. These structures ought to be analyzed on larger materials of both normal and pathological fetuses. One of the more obvious perspectives opened up by the present study is the probable disclosure of malformations in spontaneously aborted fetuses without external malformations.

The purpose of this study was to determine whether the morphology of the midface differed in normal (Class I) and midfacially-retrognathic (Class III) prepubertal subjects, and to localize differences morphometrically. Lateral cephalographs of 133 European-American children between 5-11 years of age were traced and average geometries, scaled to an equivalent size, were generated based upon seven nodes (pterygoid point, PTS; rhinion, RO; posterior nasal spine, PNS; midpalatal point, MPP; anterior nasal spine, ANS; subspinale, A; and prosthion, Pr). The samples also were subdivided into seven age- and sex-matched groups for morphometric comparisons. Procrustes analysis indicated that the overall midfacial configurations differed statistically (P < 0.05). Therefore, a color-coded finite element (FEM) program was used to localize differences in morphology graphically. Comparing Class I and III groups for size-change, FEM revealed that negative allometry was evident in the posterior half of the midfacial configuration localized between PTS, PNS, and MPP. The anterior half was more isotropic, however, but the anterior-most aspect of the configuration between Pr and RO showed some positive allometry particularly in the premaxillary and incisor regions. For shape-change, major differences in shape over the entire midface were not as evident, with an isotropic midfacial morphology for normal and Class III subjects. It is concluded that an identifiable pattern of deformation is evident for the Class III subjects during the prepubertal growth period. Therefore, midfacial retrognathia associated with Class III malocclusions results, at least in part, from deficient anteroposterior elongation of the midfacial complex allied with deformation of the premaxillary region.

The aim of the study was to analyze craniofacial development in 54 patients with osteogenesis imperfecta (OI), who were classified into OI types I, III, and IV according to clinical criteria, and to relate the findings to the abnormalities in collagen I production. In 33 patients, analysis of radioactively labelled procollagen was performed. Cephalometric radiographs, facial photographs, and CT-scans (a single case) were analyzed and mean facial diagrams for lateral and frontal films were produced based on registration of 221 reference points. Radiographs of 102 male and 51 female Danish students served as control material. In OI type I, size of the skull and jaws was generally slightly reduced, but morphology was within normal limits. In OI type IV and especially type III more severe abnormalities were found; the cranial base was flattened, the maxilla posteriorly inclined, and nearly all size-measurements were reduced. In OI type III the sagittal jaw relations were reduced and a mandibular overjet recorded. Three OI type I patients, whose fibroblasts produced structurally abnormal collagen I, had the stature and several features in the craniofacial region, which corresponded to those recorded for the OI type IV group. Also, in three OI type IV patients whose fibroblasts produced a reduced amount of normal collagen I, craniofacial morphology showed several features resembling type I patients. We conclude that structural abnormalities of collagen I generally give rise to more severe alterations of the craniofacial features than a quantitative defect of collagen I. OI type I patients are only slightly affected in their craniofacial region, while patients with OI type IV and especially type III are moderately to severely affected. The combined cephalometric and biochemical findings suggest that future classification of patients with osteogenesis imperfecta should be based on biochemical/molecular and radiological analyses in combination with clinical criteria rather than on clinical features alone.

Aspartylglucosaminuria (AGU) is a lysosomal storage disorder with progressive mental retardation as a presenting manifestation. The disorder is caused by a single nucleotide change in the gene encoding aspartylglucosaminidase (AGA). This rare disease is relatively common in Finland: we were able to examine 81 Finnish AGU-patients for dental and oral changes. Tooth crown size and crown shape were normal, but dental malocclusions were common, and prevalences of spacing, large overjet, anterior open bite, and lateral crossbite exceeded Finnish population prevalences (P < 0.0001). Dental arches were already large in childhood, and in adult patients, when compared to Finnish population standards, the lower dental arch was larger in all dimensions (P < 0.001). Almost all patients had abnormally large tongues, which we assumed to be the reason for the structural abnormalities observed.

Nonsyndromic cleft lip with or without cleft palate (CL/P) has an incidence of 1.5 per 1,000 live births in Chile, with 1.7 per 1,000 in males and 1.3 per 1,000 in females, which is nearly the same as the level found in Asian populations. The high rate of occurrence of CL/P in Chile is probably due to the presence of Amerindian genes in Chilean populations. Using the computer program PAP, a complex segregation analysis of CL/P was conducted for 67 multigeneration pedigrees from Chile, each ascertained from one affected proband. These pedigrees yielded 162 affected individuals and over 898 family members who were included in the analysis. The most parsimonious model of transmission indicated the presence of an autosomal dominant gene with reduced (20-25%) penetrance.

At the outset of the 20th century in England there arose a venomous dispute between Mendelian geneticists such as Bateson and anti-Mendelian biometricians such as Pearson over the genetic etiology of such "physical deformities" as cleft lip and palate. To Pearson et al., such traits were an expression of physical and racial degeneracy which could be traced to polygenically poor protoplasm. To Bateson et al., such traits were Mendelian unit characters whose segregation could be seen in carefully constructed family pedigrees. Bateson dismissed the work of the anti-Mendelians as "unsound in construction" and predicted such thinking would inevitably lead to "brutal" control of those the larger society deemed unfit. History proved Bateson astutely prescient.

The purpose of the present study was to investigate whether the course of Meckel's cartilage could reveal the mandibular movements during the elevation and fusion of the soft tissue palatal shelves. Histological sections, cut serially in the horizontal plane from 64 human mandibles, 16-104 mm CRL, were analyzed. The course of the anterior and medial part of Meckel's cartilage changed markedly during the three palatal stages, i.e., before, during, and after palate formation. The medial part changed during these stages from a straight course through a curled, S-shaped course to a crochet-hook-shaped course. The anterior part of Meckel's cartilage developed from a separation in the symphysis menti region to a fusion and later to a separation again. It is suggested that these changes in the course of Meckel's cartilage are due to different muscle activities. It is supposed that during the palatal developmental stages the activity of the geniohyoid and genioglossus muscles caused the mandibular retraction and the widening of the angulation between the bilateral hemimandibles. The S-shape of Meckel's cartilage is a result of these movements. Later mandibular proclination and narrowing of the bilateral hemimandibles resulted in an anterior mechanical fusion of Meckel's cartilage due to the activity of the mylohyoid muscle. This stage is followed by a retraction and re-widening of the angulation between the bilateral bony components, which disrupts the fusion of Meckel's cartilage in the symphysis menti region. Thus, the course of Meckel's cartilage revealed the mandibular movements in the sagittal and transverse planes during palate formation.

The object of this investigation was to determine whether children of the same age with different headforms differ in their three-dimensional soft-tissue facial characteristics. The three-dimensional coordinates of 22 standardized facial landmarks were automatically collected in a sample of 70 boys and 71 girls age 11 to 13 years attending a junior high school. From the collected landmarks, several three-dimensional facial angles, linear distances, linear distance ratios, and volumes were calculated. For each subject the cephalic index (maximal head breadth/ maximal head length x 100) was computed and three groups of measurements for each sex were obtained (dolicho-, meso- and brachycephalic). A two-way factorial analysis of variance compared the effects of sex and headform, and the interaction sex x headform. On average, boys had significantly (P < or = 0.05) longer and wider faces than girls, with a larger lower third facial volume relative to middle third facial volume. A significant (P < or = 0.05) effect of headform over facial morphology was found for all angles with a prevalent axial orientation. Conversely, no effect was demonstrated for angles with a sagittal orientation, nor for any other considered parameters. For each sex, the dolichocephalic children had smaller values than the brachycephalic children (i.e., more convex faces in the left-right direction), while the mesocephalic children had intermediate values. No sex x headform interactions were found. Results confirm that a different headform (skull) is associated with a different three-dimensional facial morphology (combined effect of skull and soft tissues), but without size differences.

Since the 1890s oral biological researchers have been interested in the idea that strenuous mastication of unprocessed food will stimulate proper oral-facial growth and occlusal relationships. Conversely, lack of such function due to consumption of refined food is one hypothesis among many for the etiology of malocclusion in industrialized humans. Adequately controlled experimental testing of the idea has been limited to rats. To investigate the "disuse" theory in a larger-bodied and more occlusally relevant animal model, we raised four Yucatan minipigs from weaning on hard diet (HD) and another four on softened but equivalent diet (SD). The animals were monitored for eight months, sacrificed, and then occlusal and osteometric data collected. Variations due to dietary regime are pervasive and not due to caries, periodontitis, or attrition differences. Whereas HD body weight is 10% greater than SD, the deep masseter is 25% greater, with similar disproportion in superficial masseter and temporalis weight. Facial prognathism, arch narrowness, tooth crowding/maleruption and posterior cranial tapering are markedly different in the two groups. A curious posterior torsional difference in the mandibular rami, as well as broadness and flatness of the mandibular symphysis, also occur in SD. We performed a Q-mode principal coordinates analysis of the 19 logged variables for the specimens, bootstrapping the variable list, to demonstrate a statistically significant (P < .01) overall pattern of dramatic differences. Having controlled other celebrated orthodontic etiologies (genetic background, respiratory mode, infectious degeneration and interproximal attrition), these results support the proposition that dietary consistency relates directly to human craniofacial growth.

Microradiographic and histological analyses point out a focal disturbed chondrogenesis of both the skull base and the axial skeleton in a case of oculo-auriculo-vertebral spectrum. Cartilage showed disturbed endochondral ossification with defects in calcification, deficient resorption, and abnormal crumpled areas of mineralized cartilage.