Craniofacial morphology in young patients with Turner syndrome

Developmental Abnormalities of the Skull Base in Patients with Turner Syndrome

The skull base is one of the most complex anatomic structures of the skeleton that is responsible for protecting and supporting the brain and is also involved in the development of the facial structures. The main objective of our study was to evaluate skull base abnormalities in a group of patients diagnosed with Turner syndrome by assessing lateral cephalometric radiographs. A total of 7 patients diagnosed with Turner syndrome in the Endocrinology Department of the Emergency Clinical County Hospital of Craiova were included in the study. The following cephalometric variables were measured in our study: total skull base (N-Ba): Nasion (N)-Basion (Ba); anterior skull base (N-S): Nasion (N)-Sella (S); posterior skull base (S-Ba): Sella (S)-Basion (Ba). Regarding the investigated cephalometric variables, the mean±standard deviation (SD) recorded values in our study were 86.34±4.26mm for the total skull base (N-Ba), 63.87±2.54mm for the anterior skull base (N-S) and 38.33±4.87mm for the posterior skull base (S-Ba). The results of our study were compared to the ones provided by one of the most representative studies described in the literature. A reduced size of the posterior base of the skull is considered pathognomonic in subjects diagnosed with Turner syndrome. Also, the posterior base of the skull directly influences the maxillomandibular skeletal relationships and it is therefore necessary to calculate this cephalometric variable, which is easily highlighted on a lateral cephalometric radiograph.

Tooth Crown Morphology in Turner and Klinefelter Syndrome Individuals from a Croatian Sample

Objective

Turner syndrome (TS) and Klinefelter syndrome (KS) represent the two most common X chromosome aneuploidies, each associated with systemic disruptions to growth and development. Effects of these conditions on tooth crown morphology are explored in a sample of Croatian individuals.

Materials and Methods

The sample included 57 TS, 37 KS and 88 control individuals. Dental crown morphology was scored on dental casts according to the Turner-Scott Dental Anthropology System.

Results

Incisor shoveling and the hypocone were significantly different between TS individuals and both control and KS individuals. Individuals with TS exhibit lower grades of expression than either group. Furthermore, the number of lingual cusps on the mandibular premolars, the hypoconulid on the mandibular second molar, and cusp 7 on the mandibular first molar were significantly different, though pair-wise comparisons did not elucidate these differences. Tuberculum dentale, distal accessory ridge, and Carabelli's trait were expressed similarly to the control. KS individuals were not significantly different from control individuals for any trait, though this may be related to sample size.

Conclusions

Previous studies suggest the loss of an X chromosome has a reducing effect on dental crown morphology, which is confirmed in this research. TS individuals exhibit generally simpler dental morphology compared to the control sample, though some traits are expressed comparably to the control sample. The effects of KS are less clear. Though previous studies suggest that the presence of an extra X chromosome increases dental crown dimensions, there was no notable effect on crown morphology in this study.

The Role of Ellis-Van Creveld 2(EVC2) in Mice During Cranial Bone Development

EvC syndrome is a type of autosomal-recessive chondrodysplasia. Previous case studies in patients suggest abnormal craniofacial development, in addition to dwarfism and tooth abnormalities. To investigate how craniofacial development is affected in EvC patients, surface models were generated from micro-CT scans of control mice, Evc2 global mutant mice and Evc2 neural crest-specific mutant mice. The anatomic landmarks were placed on the surface model to assess the morphological abnormalities in the Evc2 mutants. Through analyzing the linear and angular measurements between landmarks, we identified a smaller overall skull, shorter nasal bone, shorter frontal bone, and shorter cranial base in the Evc2 global mutants. By comparing neural crest-specific Evc2 mutants with control mice, we demonstrated that the abnormalities within the mid-facial regions are not accounted for by the Evc2 mutation within these regions. Additionally, we also identified disproportionate length to width ratios in the Evc2 mutants at all levels from anterior to posterior of the skull. Overall, this study demonstrates a more comprehensive analysis on the craniofacial morphological abnormalities in EvC syndrome and provides the developmental insight to appreciate the impact of Evc2 mutation within the neural crest cells on multiple aspects of skull deformities. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:46-55, 2018. © 2017 Wiley Periodicals, Inc.

Growth hormone positive effects on craniofacial complex in Turner syndrome

OBJECTIVE

Turner syndrome occurs in phenotypic females with complete or partial absence of X chromosome. The leading symptom is short stature, while numerous but mild stigmata manifest in the craniofacial region. These patients are commonly treated with growth hormone to improve their final height. The aim of this study was to assess the influence of long-term growth hormone therapy on craniofacial morphology in Turner syndrome patients.

DESIGN

In this cross-sectional study cephalometric analysis was performed on 13 lateral cephalograms of patients with 45,X karyotype and the average age of 17.3 years, who have received growth hormone for at least two years. The control group consisted of 13 Turner syndrome patients naive to growth hormone treatment, matched to study group by age and karyotype. Sixteen linear and angular measurements were obtained from standard lateral cephalograms. Standard deviation scores were calculated in order to evaluate influence of growth hormone therapy on craniofacial components.

RESULTS

In Turner syndrome patients treated with growth hormone most of linear measurements were significantly larger compared to untreated patients. Growth hormone therapy mainly influenced posterior face height, mandibular ramus height, total mandibular length, anterior face height and maxillary length. While the increase in linear measurements was evident, angular measurements and facial height ratio did not show statistically significant difference. Acromegalic features were not found.

CONCLUSIONS

Long-term growth hormone therapy has positive influence on craniofacial development in Turner syndrome patients, with the greatest impact on posterior facial height and mandibular ramus. However, it could not compensate X chromosome deficiency and normalize craniofacial features.

Karyotyping, dermatoglyphic, and sweat pore analysis of five families affected with ectodermal dysplasia

Background:

Hereditary ectodermal dysplasia is a genetic recessive trait characterized by hypohydrosis, hypotrichosis, and hypodontia. The affected individual show characteristic physiognomy like protruded forehead, depressed nasal bridge, periorbital wrinkling, protruded lips, etc. There is marked decrease in sweat and salivary secretion. Due to skin involvement palm and sole ridge patterns are disrupted.

Aim:

In this study an attempt has been made to classify the affected members according to the degree of penetrance by pedigree analysis and also study karyotyping for cytogenetics, dermatoglyphic analysis for the various ridge patterns and variations in the number of sweat glands by sweat pore analysis in affected individuals.

Materials and Methods:

A total of five families who were affected with ectodermal dysplasia were considered. Pedigree analysis was drawn up to three generation by obtaining history. Dermatoglyphics and sweat pore analysis was done by obtaining palm and finger print impression using stamp pad ink. Karyotyping was done by collecting 3–5 ml peripheral blood. Karyotyping was prepared using lymphocyte culture. Chromosomes were examined at 20 spreads selected randomly under ×100 magnification. Results were analyzed by calculating mean values and percentage was obtained.

Results:

Karyotyping did not show any abnormalities, dermatoglyphic analysis and sweat pore counts showed marked variations when compared with normal. Moreover, pedigree analysis confirmed the status of the disease as that of the recessive trait.

Conclusion:

Large number of affected patients needs to be evaluated for dermatoglypic analysis. Genetic aspect of the disease needs to be looked into the molecular level in an attempt to locate the gene locus responsible for ectodermal dysplasia and its manifestation.

Ontogenetic changes of craniofacial complex in Turner syndrome patients treated with growth hormone

OBJECTIVE

The present study assessed changes of craniofacial complex in Turner syndrome (TS) patients treated with growth hormone (GH) during development. The objective was to examine the growth rate and pattern of craniofacial structures and to establish effects of GH on craniofacial development.

MATERIALS AND METHODS

The study population consisted of 15 TS patients treated with GH aged 5-18.5 years (13.3 ± 4.4) and corresponding control group of 45 females aged 6.8-18.7 (11.4 ± 2.6). According to the stage of cervical vertebral maturation, subjects were categorized into pre-growth (5 TS and 15 controls) and growth (10 TS and 30 controls) subgroups. The cephalometric analysis comprised angular and linear variables, measured on lateral cephalometric radiographs.

RESULTS

The mandibular corpus/anterior cranial base ratio increased significantly only in controls during development. In growth period, ramus/corpus ratio was significantly larger in TS group. SNA and SNB angles were significantly smaller in TS growth subgroup compared to corresponding controls. Among other variables, no statistically significant differences were revealed.

CONCLUSIONS

In TS patients treated with GH, growth capacities of cranial base and maxilla are adequate which can be attributed to GH treatment. Shape of mandible is altered due to decreased growth of corpus and overdeveloped ramus. Both maxillary and mandibular retrognathism are becoming more expressed during development.

CLINICAL RELEVANCE

Favorable influence of GH on craniofacial complex growth rate and altered growth pattern revealed in this study should be considered while planning both orthodontic treatment and retention.

Cephalometric analysis of pharyngeal airway space dimensions in Turner syndrome

Turner syndrome (TS) that is due to a total or partial lack of an X chromosome affects about 1 in 2000 girls. The syndrome is characterized by short stature and gonadal dysgenesis. Its documented craniofacial features include retrognathic jaws, a short mandible, and a large cranial base angle. Our aim was to find out whether the syndrome also has an effect on the pharyngeal airway space. We retrospectively analysed lateral cephalograms of 35 TS subjects whose age ranged from 6.5 to 21 years and of 35 healthy female controls matched for age. On those, we did 7 linear and 10 angular cephalometric measurements and 9 pharyngeal measurements. Differences between the subjects with TS and their controls were assessed by paired two-tailed T-test. In the girls with TS, both the maxilla and the mandible were more retrognathic (SNA, P = 0.015 and SNB, P < 0.001), the mandible was shorter (TM-Pgn, P = 0.016), and the cranial base angle was larger (SNBa, P = 0.025) than in the controls, confirming the results of earlier studies. Notably, all six pharyngeal airway measurements were smaller in girls with TS. Two of them, PNS-ad2 and PAS, were statistically significantly smaller (P = 0.019 and P = 0.012, respectively). Thus, a narrow pharynx, either as a primary finding or as a consequence of the maxillo-mandibular retrognathism, further delineates the phenotype. This may imply an elevated risk of sleep apnoea in females with TS.

Developmental expression of Dkk1-3 and Mmp9 and apoptosis in cranial base of mice

The Dickkopf (Dkk) family and Mmp9 are important for apoptosis and a number of other developmental processes. However, little is known about their roles in the development of cranial base, which is an important structure for coordinated development and growth of the craniofacial skeletons. In order to establish whether and in what way these genes are involved in cranial base development, we examined their expression patterns and cell apoptosis. Dkk1 was first seen in the perichondral mesenchyme in restricted domains from E14, and later in the migrating mesenchymal cells within the cartilage. Thereafter, it was widespread throughout the bones of the cranial base. The expression was downregulated in postnatal stages. Dkk2 was localized in the perichondral mesenchyme outlining the anterior cranial base in embryogenesis. Dkk3 was mainly detected in the occipital-vertebral joint at E13 and E14. Mmp9 transcripts were clustered in the inner layer of perichondral mesenchyme, juxtaposed with the terminally differentiated hypertrophic chondrocytes from E14. Later Mmp9-expressing cells were found at the sites of chondrocyte apoptosis. This was particularly clear at the distal ends of the synchondroses. These data indicate that Mmp9 regulates skeletogenesis in cranial base in a manner that is largely similar to that of the appendicular skeletons. Expression of Dkks suggests other roles that remain to be defined.

Cranial base in craniofacial development: developmental features, influence on facial growth, anomaly, and molecular basis

The cranial base is of crucial importance in integrated craniofacial development. As distinct from facial bones, it is formed through endochondral ossification. The posterior and anterior cranial bases are derived from distinct embryologic origins and grow independently--the anterior cranial base solely from the neural crest, the posterior cranial base from the paraxial mesoderm. The anterior cranial base has more prolonged and active growth and exerts more influence on facial growth than does the posterior cranial base. Cranial base angulation is a unique feature in modern human beings. Cranial base anomalies have been identified in many genetic and developmental disorders. The molecular basis of cranial base development and growth is being clarified. In this review, these aspects of cranial base are discussed in detail, with a focus on developmental features, roles in craniofacial growth, anomalies, and the genetic basis of development.

Phenotype, ovarian function, and growth in patients with 45,X/47,XXX Turner mosaicism: implications for prenatal counseling and estrogen therapy at puberty

OBJECTIVE

Our objective was to determine whether girls with the rare Tur-ner 45,X/47,XXX mosaic karyotype are less severely affected than girls with 2 commoner karyotypes.

STUDY DESIGN

We evaluated growth status, phenotype, and ovarian function in 7 girls with 45,X/47,XXX mosaicism, age-matching each with 2 girls with 45,X and 1 with 45,X/46,Xi(X)(q10) karyotypes.

RESULTS

For the index, 45,X, and 45,X/46,Xi(X)(q10) groups, respectively, the median/mean height SD score at the start of growth hormone therapy/comparable age was -2.0 (-1.2), -2.3 (-2.4), and -2.6 (-2.6), cardiac anomalies were identified in 0 of 7, 4 of 14, and 1 of 7, renal abnormalities in 0 of 7, 4 of 14, and 3 of 7, middle ear problems in 2 of 7, 11 of 14, and 4 of 7, and special educational needs in 0 of 7, 3 of 14, and 1 of 7. Complete spontaneous puberty with menarche was seen in all but 1 girl older than 12 years in the index group compared with only 1 girl in the comparison groups. Ovarian tissue was identified in 6 of 7, 0 of 14, and 1 of 7 girls, and the mean follicle-stimulating hormone was 6, 25, and 21 U/L, respectively.

CONCLUSION

Girls with 45,X/47,XXX karyotype are mildly affected, with good preservation of ovarian function. This result has important implications for prenatal counseling and the need for estrogen therapy at puberty.