Morphology of the sella turcica in Axenfeld-Rieger syndrome with PITX2 mutation

Morphometric Analysis of the Sella Turcica on Cone-Beam Computed Tomography Images

INTRODUCTION

Sella turcica is an important anatomic formation that contains the pituitary gland and is in a close neighborhood with many vital structures. It is important to know the morphometry of the sella turcica, as it is a transition point during surgical interventions such as the endoscopic endonasal transsphenoidal approach to the region. The findings obtained are thought to be useful in the examination of sella turcica and surrounding structures and will contribute to the literature by knowing the morphometry of the region for the surgical method.

METHOD

In this study, cone-beam computed tomography images of 400 individuals, 200 females and 200 males, aged between 18 and 65 years, who did not have craniofacial pathology, who applied to Gaziantep University, Faculty of Dentistry between 2015 and 2020 for any reason, were evaluated retrospectively. In the sagittal section, 8 parameters were examined, 6 of which were transverse.

RESULTS

The length () of the sella turcica in the sagittal plane is 10.19±1.77 mm, the diameter of the sella turcica is 11.6±1.69 mm, the anterior height of the sella turcica is 7.88±1.56 mm, the median height of the sella turcica 8.18±1.42 mm, posterior height of sella turcica 6.98±1.31 mm, width of sella turcica 11.10±1.6 mm. The distance between anterior clinoid processes in the transverse plane was 24.93±2.57 mm, and the distance between posterior clinoid processes was 14.92±2.46 mm.

CONCLUSION

It was determined that there was an increase in many parameters with age, and length of the sella turcica and anterior clinoid processes were statistically significantly higher in males.

Evaluation of Sella Turcica Morphology and Morphometry Based on Gender and Age in Our Population Using Computed Tomography

In this study, it was aimed to determine the reference values for the healthy Turkish population by evaluating the age-related changes in the morphology and morphometry of Sella Turcica (ST) and the relationship with the body mass index. In addition, it has been investigated whether the morphology and morphometry of this structure vary in diabetes mellitus (DM) patients. The study group was consisted of a total of 524 individuals (266 females and 258 males) (426 healthy and 48 with DM) between the ages of 1 and 80, who applied to the Department of Radiology between January 2018 and February 2021. Axial brain computed tomography scans which have no pathology in ST were retrospectively examined. The ST length (STL), height (STH), diameter (STD), processus clinoideus anterior right-left (PCAR_L), processus clinoideus posterior right-left (PCPR_L) did not differ significantly in healthy individuals and individuals with DM (P>0.05). When the ST morphology according to the ST shape classification performed by Meyer Marcotti and colleagues and Axellson and colleagues was evaluated, it was observed that there was no statistically significant difference between the 2 groups (P>0.05). There was a significant difference in STL, STD values (P<0.05), however, there was no difference in STH, PCAR_L, PCPR_L values between genders (P>0.05). While the distance between STL, STD, PCAR_L showed a significant difference between the decades in all groups, there was no significant difference in the STH, PCPR_L in both classifications (P>0.05). When the relationship between the parameters and body mass index was evaluated, STL, STD, PCAR_L showed a significant difference between the groups (P<0.05). Detailed knowledge of the ST anatomy will be helpful in terms of early diagnosis of diseases that may be related and guiding surgical interventions in this region.

Association between sella turcica bridging and the impaction severity of palatally displaced canines: A retrospective study

INTRODUCTION

This retrospective study aimed to investigate the association between the extent of the bridging and dimensions of sella turcica and the impaction severity of palatally displaced canines. Secondarily, any possible association between skeletal age and gender was evaluated.

METHODS

Panoramic and cephalometric radiographs of 94 patients (63 female, 31 male; 19 pre-peak, 75 post-peak) with palatally displaced canines were evaluated. Sector classification and α angle were used to determine the impaction severity of palatally displaced canines on panoramic radiographs. The distance from the cusp tip of the palatally displaced canines to the occlusal plane (d) and the extent of the bridging and dimensions of the sella turcica were evaluated on cephalometric radiographs.

RESULTS

Sella turcica bridging and dimensions did not vary regarding the impaction severity of palatally displaced canines, but a significant association was found between sella turcica bridging and skeletal age (P = 0.038). Class II (33.3%) and Class III (12.0%) bridging was higher in postpubertal patients. No differences between females and males were detected for the extent of bridging and dimensions of the sella turcica.

CONCLUSIONS

These findings indicate no association between sella turcica bridging and dimensions and the impaction severity of palatally displaced canines. Sella turcica bridging is more frequent in the postpubertal period, whereas gender does not influence sella turcica bridging. More studies are needed to evaluate if the extent of sella turcica bridging may be indicative of severely impacted palatal canines, which in turn would allow for careful monitoring of patients from an early age and for the clinician to take preventive measures.

Pitx2 suppression at meiotic stages associates with seasonal inhibition of testis development in Rattus norvegicus caraco

The bicoid-related transcription factor 2 (Pitx2) plays a crucial role in the development of many organs and tissues by affecting the mitotic cell cycle. Postnatal testis development is related to mitosis and meiosis in multiple cell types, but the role of Pitx2 gene in seasonal inhibition of testicular development remains unknown in rodents. We analyzed PITX2 protein and Pitx2 mRNA expression features using both laboratory and wild male Rattus norvegicus caraco. In postnatal testicle of laboratory colony, we found that PITX2 was expressed in Leydig cells, pachytene spermatocytes, round spermatids, and elongating spermatids rather than spermatogonia and leptotene/zygotene spermatocytes. Pitx2b expression significantly increased along with the occurrence of pachytene spermatocytes and round spermatids, while decreased along with the processes of elongated spermatids. In wild male rats with similar testes weight, a significantly suppressed Pitx2b expression occurred with an active meiotic stage in the inhibited testes in autumn and winter, compared with the normally developing testes in spring and summer. These results indicate that Pitx2b expression suppression plays a crucial role in the seasonal inhibition of testis development.

Craniofacial and dental features of Axenfeld-Rieger syndrome patients with PITX2 mutations

We aimed to characterize the genetic basis and craniofacial and dental features of Finnish patients with Axenfeld-Rieger syndrome (ARS). Mutational analyses of seven patients in five families were performed by sequencing or comparative genomic hybridization. Phenotypic analysis was based on both clinical and radiographic examinations, as well as on medical data. Lateral cephalometric radiographs of five patients were analysed using Viewbox 3.1-Cephalometric Software. The cephalometric values were compared to Finnish population-standard values of the same age and gender. Two frameshift mutations and three whole gene deletions were detected in five families. Class III skeletal relationship with retrognathic maxilla and mildly retrognathic mandible were detected in all five patients studied. Significant differences compared with the control values were in SNA (P = .0014), ANB (P = .0043) and SNB angles (P = .013). Five patients had anterior crossbite. Six patients showed tooth agenesis. The average number of missing teeth (third molars excluded) was 9 (range 0-15). The tooth agenesis rate was 52% in maxilla and 26% in mandible. Maxillary central and lateral permanent incisors were most often missing (rate 71% equally) while no one lacked canines or first molars in mandible. Two patients had a supernumerary mandibular permanent incisor. Six patients had either taurodontic and/or single-rooted molars. Our results suggest that class III skeletal relationship with maxillary and mandibular retrognathism, anterior crossbite, maxillary incisor agenesis and taurodontic, even pyramidal, roots are common determinants of ARS caused by PITX2 mutations.

Relationship between palatally impacted canines and dimensions and morphology of sella turcica: A cone-beam computed tomography study

INTRODUCTION

This study aimed to analyze the association of unilateral and bilateral palatal canine impaction with the dimensions and morphology of sella turcica from 3-dimensional cone-beam computed tomography (CBCT) images.

METHODS

CBCT images of patients with bilateral (BPI) (n = 12; 9 female 3 male; 20.75 ± 5.88 years) and unilateral (UPI) (n = 35; 22 female 13 male; 19.28 ± 5.57 years) palatally impacted canines were compared with a control group (n = 56; 34 female 22 male; 20.82 ± 4.88 years). Linear measurements regarding sella turcica were made, and its morphologic variations were categorized. Two group comparisons were made with the Student t test or Mann-Whitney U-test, whereas one-way analysis of variance or Kruskal-Wallis tests were used for multiple group comparisons. Categorical variables were compared using the chi-square or Fisher exact test as appropriate. The binary logistic regression analyses and correlations using Spearman or Pearson correlation analyses were used to determine associations between variables (P <0.05).

RESULTS

Sella diameter was significantly smaller in the BPI group compared to UPI and control groups. There was a significant association between sella diameter and BPI when compared with the control group (χ2[1] = 9.150; P = 0.008). There were no significant differences between groups in the distribution of sella turcica morphology.

CONCLUSIONS

Despite the similar genetic origin of the sella turcica region and teeth, the association of palatal canine impaction with dimensions and morphology of sella turcica was weak. Both local and genetic factors might contribute to the ectopic position of the canine.

Sella Turcica Bridging and its Association with Dental Anomalies

Aim:

This study aimed to study the overall incidence of DA and its association with Sella Turcica bridging (STB).

Background:

Dental anomalies (DA) are associated with morphological changes in the Sella Turcica (ST).

Materials and Methods:

We retrieved the pretreatment patient records from March 2018 - March 2020 from the archives of the Orthodontics Department (n=806). We excluded the records with missing radiographs, concomitant cleft lip/ palate, history of surgical repair of cleft lip/ palate or any other craniofacial anomaly, history of trauma, and prior orthodontic treatment. A total of 676 patient records were included for initial screening, out of which 103 patients had DA (study group). A similar number of records (n=103) without any DA were randomly selected to constitute a control group. Determination of the extent of STB was done by calibrated and trained examiner. Age and sex were also recorded.

Results:

The incidence of DA was 15.24%. The most common anomalies recorded were impacted canines (6.8%) and hyperdontia (3.7%), followed by agenesis (2.1%) and others. Type III bridging in patients with DA was 22.3%, while being 9.7% in the control group. Type II bridging was observed in 36.8% of patients with DA as compared to 29.1% in the control group. The presence of partial and complete STB in patients with dental anomalies was significantly higher than in the control group (P=0.006). The study group showed significant association with STB (OR: 2.33; P=0.003; 95%CI: 1.33-4.11) after adjusting for sex.

Conclusion:

The results of our study revealed a significant association between STB and DA.

Is there a relationship between transverse maxillary deficiency and sella turcica: A cephalometric analysis study?

Objectives:

The aim of this study was to investigate the dimensions and morphological variations of sella turcica and to test whether a relationship exists between sella turcica and transverse maxillary deficiency.

Materials and Methods:

The cephalometric radiographs of patients older than 17.99 years, which have been taken before the orthodontic treatment, and patient records were analyzed to investigate sella turcica dimensional and morphological analysis. Linear measurements of sella are as follows sella length, sella width, sellar area, sella height anterior, posterior, and median. The sella turcica morphological shape analysis was performed into six groups (normal sella turcica, oblique anterior wall, sella turcica bridge, double contour of floor, irregularities of the posterior part of the dorsum sella, and pyramidal shape of the dorsum sella). The width of the maxillary arch is measured by the digital caliper. Male participants with a maxillary width of less than 30.8 mm and a maxillary width of less than 31.1 mm in female patients in the first molar region were determined as a transverse maxillary deficiency. The mean dimensions of sella turcica and the relationship between cases with transverse maxillary deficiency and non-skeletal anomaly were compared using independent samples t-tests. The transverse maxillary deficiency and the sellar morphology relationship were compared using Chi-square test. Post hoc multiple comparisons and analyzes were performed at 95% confidence interval by Bonferroni correction.

Results:

The sella length measurements yielded higher values among the patients with transverse maxillary deficiency (P < 0.05). The normal sella morphology had quantitative superiority in patients without skeletal anomaly in comparison with transverse maxillary deficiency cases (P < 0.05). It was observed that the sella turcica bridge had a statistically superiority in patients with transverse maxillary deficiency (P < 0.05).

Conclusion:

The increased sellar measurement and sella turcica bridging, may provide knowledge about possible transverse maxillary deficiency.

Diagnostic accuracy of lateral cephalograms and cone-beam computed tomography for the assessment of sella turcica bridging

INTRODUCTION

The purpose of this research was to assess the diagnostic accuracy of sella turcica bridging on lateral cephalograms when compared with true sella turcica bridging determined via cone-beam computed tomography (CBCT).

METHODS

A cross-sectional study was conducted using CBCT images from which lateral cephalograms were generated. The study included 185 subjects (118 females and 67 males; age range, 10-30 years; mean age, 16.63 ± 4.20 years). Sella turcica landmarks and related measurements were calculated for both diagnostic modalities and analyzed by 1 examiner. Subjects were classified into 1 of 3 outcome groups: no bridging, partial bridging, and complete bridging. Diagnostic accuracy was evaluated using sensitivity, specificity, positive and negative predictive values, and receiver operator characteristic curves.

RESULTS

Ten patients were diagnosed as complete bridging on CBCT, whereas 31 patients were diagnosed as complete bridging on lateral cephalogram. Although the lateral cephalogram detected all subjects with complete bridging, it incorrectly classified 12% of subjects. The percent agreement between both diagnostic methods was 55.68%, with a kappa statistic of 0.22 on the right sella turcica and 0.20 on the left sella turcica, indicating fair but statistically significant agreement. The overall accuracy of lateral cephalograms as a diagnostic modality in discriminating between no bridging and partial bridging was good as determined with the area under the curve values of 0.86 and 0.85 for right and left sides, respectively.

CONCLUSIONS

Although lateral cephalograms overestimate patients with complete bridging compared to CBCTs, they are a suitable screening modality for accurately suggesting complete sella turcica bridging and differentiating between patients with no bridging and partial bridging.

Sella Turcica Morphology in Patients With Genetic Syndromes: Protocol for a Systematic Review

Background

The sella turcica is an important anatomical reference used in orthodontics and the evaluation of craniofacial growth. Studies have found an association between variations in sella turcica morphology in patients with certain syndromes affecting the craniofacial complex. It is hypothesized that each related syndrome or pathological condition is associated with a specific pattern of malformation of the sella turcica.

Objective

This study outlines the protocol for a systematic review that aims to determine if genetic syndromes involving the craniofacial complex are associated with abnormal radiographic sella turcica morphology and if there is a pattern of malformation that is consistent with each syndrome.

Methods

An electronic database search was conducted using a planned search strategy to identify relevant studies. We included primary studies evaluating the morphology of the sella turcica based on imaging from a lateral view. Specifically, only studies with postnatal human participants with genetic syndromes involving the craniofacial complex were included in this review. We placed no restrictions on the language or time frame of these studies. Based on the search findings, studies were further screened for relevance and eligibility by two independent reviewers. Data were extracted from the selected studies. We assessed the selected studies for risk of bias and quality by using risk of bias tools from the Joanna Briggs Institute. We will provide a narrative synthesis of our findings and a structured summary based on prespecified themes.

Results

The protocol is registered with PROSPERO (#CRD42019148060) and approved by the University of Western Cape Biomedical Science Research Ethics Committee (BM205/3). The literature search was conducted in September 2019 and updated in July 2020. The study was completed in August 2020, and the findings will be published in an open-access journal.

Conclusions

The results of this systematic review are expected to provide a comprehensive list of morphological variations of the sella turcica, which will aid in the identification of syndromes associated with the craniofacial complex. We also expect to identify patterns of sella turcica morphology that highlight genotype-phenotype correlations, thus adding to the body of evidence relating to genetics and craniofacial malformations.

Trial Registration

PROSPERO International Prospective Register of Systematic Reviews CRD42019148060; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=148060

International Registered Report Identifier (IRRID)

RR1-10.2196/16633

Sella turcica morphology in patients with genetic syndromes: A systematic review

The sella turcica is an important anatomical reference used in orthodontics for the evaluation of craniofacial growth. Studies have found variations in the sella turcica morphology in patients with syndromes affecting the craniofacial complex. This review aims to determine whether genetic syndromes involving the craniofacial complex are associated with abnormal radiographic sella turcica morphology and whether there is a pattern of malformation which is consistent within each syndrome. An electronic database search was conducted to identify relevant studies. We included primary studies describing the morphology of the sella turcica on lateral radiographs in human subjects with genetic syndromes involving the craniofacial complex. No restrictions were placed on language or timeframe. PROSPERO registration CRD42019148060. Thirty-eight studies were included in this review. A 'J'-shaped sella was found in patients with Hutchinson-Gilford-Progeria syndrome and other syndromes. A bulbous dorsum sellae was highly prevalent Cleidocranial dysplasia, and a bulbous dorsum sellae and uneven contours of the clivus was found in Cri du chat syndrome. A steep clivus was described in patients with Axenfeld-Rieger syndrome. An oblique anterior wall was the most frequent malformation found in Down's syndrome. Genetic syndromes affecting the craniofacial complex are associated with abnormal morphology of the radiographic sella turcica. Clinicians should be observant of abnormal sella turcica morphology which can be a sign of undiagnosed or subclinical syndromes. More high-quality studies are needed which use standardized and objective methods of determining the morphology of the sella turcica.

Size and bridging of the sella turcica in Japanese orthodontic patients with tooth agenesis

The purpose of this study was to investigate the association between the size and bridging of the sella turcica and tooth agenesis, and whether the likelihood of second premolar agenesis can be predicted from the sella turcica size and bridging in Japanese orthodontic patients. Patients were divided into four groups of 32: groups 1 and 2 consisted of patients with agenesis of the maxillary and mandibular second premolars, respectively; group 3, patients with severe tooth agenesis; and group 4, patients without tooth agenesis. Each group was divided into two subgroups of 16 each based on the patient's age: patients under 14 years of age (groups 1A through 4A, group A) and patients 14 years of age or older (groups 1B through 4B, group B). Lateral cephalograms were used to evaluate the size and bridging of the sella turcica. The interclinoidal distance (ID) was significantly shorter in groups 1 and 3 than in group 4, and in group 3 than in group 2. Group B exhibited significantly greater depth, diameter, area, and perimeter of the sella turcica than group A. Groups 3 and 1B had a significantly higher prevalence of sella turcica bridging than groups 4 and 4B, respectively. Maxillary second premolar agenesis and severe tooth agenesis were associated with a reduced ID irrespective of age and increased occurrence of sella turcica bridging. The early emergence in life of a short ID might be a predictor of possible second premolar agenesis in later life.

Morphology, Incidence of Bridging, Dimensions of Sella Turcica, and Cephalometric Standards in Three Different Racial Groups

This study aims to assess the morphological appearance, incidence of bridging, linear dimensions of sella turcica and establish cephalometric standards in Bosnian, Chinese and Nepalese subjects. This retrospective study examined digital standardized lateral cephalograms of 540 subjects, which consisted of 116 females and 64 males with an age range of 8 to 28 years. The sella morphology, bridging, and size were analyzed on the lateral cephalograms. Steiner's and Rickett's analyses were performed on 270 subjects. Sella turcica presented a normal morphology in most Bosnian (86.7%), and Nepalese (90%) subjects whereas flat-shaped morphology was highly prevalent among Chinese subjects (36.7%). The frequency of full bridging was 7.2%, 2.8%, and 11.7% for Bosnian, Chinese, and Nepalese subjects, respectively. A significant correlation was detected between the length of sella turcica and gender of Bosnian subjects, whereas the size of sella turcica and gender of Chinese and Nepalese subjects were not affected. A direct correlation existed between age and size of sella turcica of Bosnian subjects. A significant correlation was detected between length and diameter of sella turcica and age in Chinese and Nepalese subjects. A statistically significant difference was found in length (P < 0.001), depth (P < 0.01) and diameter (P < 0.001) of sella turcica with race. The diameter of sella turcica was the only parameter significantly associated with race, gender and age. Significant differences were found between cephalometric norms in different racial groups. These findings assist orthodontists, neurosurgeons, and forensic medical investigatiors during orthodontic treatment planning, diagnosis of pathology of the pituitary gland, and age determination.

Novel PITX2 mutations identified in Axenfeld-Rieger syndrome and the pattern of PITX2-related tooth agenesis

OBJECTIVES

To investigate the mutations in patients with Axenfeld-Rieger syndrome (ARS) and the pattern of PITX2-related tooth agenesis.

METHODS

Whole-exome sequencing (WES) and copy number variation (CNV) array were used to screen the mutations in four ARS probands. After Sanger sequencing and quantitative polymerase chain reaction (qPCR) validation, secondary structure prediction and dual-luciferase assay were employed to investigate the functional impact. Eighteen PITX2-mutated patients with definite dental records were retrieved from our database and literatures, and the pattern of PITX2-related tooth agenesis was analyzed.

RESULTS

A novel de novo segmental deletion of chromosome 4q25 (GRCh37/hg19 chr4:111, 320, 052-111, 754, 236) encompassing PITX2 and three novel PITX2 mutations c.148C > T, c.257G > A, and c.630insCG were identified. Preliminary functional studies indicated the transactivation capacity of mutant PITX2 on Distal-less homeobox 2 (DLX2) promoter was compromised. The maxillary teeth showed significantly higher rate of agenesis (57.94%) than the mandibular teeth (44.05%). The most often missing teeth were upper lateral incisors (83.33%) and upper second premolars (69.44%). Teeth with the least agenesis rate were the lower second molars (19.44%) and lower first molars (8.33%).

CONCLUSIONS

We identified a novel 4q25 microdeletion including PITX2 and three novel PITX2 mutations, and statistically analyzed the PITX2-related tooth agenesis pattern.

Association between sella turcica bridging and congenitally missing maxillary lateral incisors

Background/purpose

Sella turcica bridging (STB) and its association with dental anomalies has been investigated and reported in literature. This is the first study that exclusively compared STB among the orthodontic patients with congenital missing maxillary lateral incisors (CMMLI) and individuals with complete dentition.

Materials and methods

The retrospective study has recruited 49 patients with CMMLI (13 males and 36 females aged between 12 and 43 years) and 49 patients with complete dentition. Sella dimensions and association of STB with CMMLI were evaluated and the results were analysed using descriptive and inferential statistics.

Results

The comparison of mean diameter, length, and depth of sella between groups showed reduction in length among the CMMLI (p = 0.04). CMMLI group has shown a significant higher (p < 0.05) number of subjects (69.4%) with calcification when compared to control group (46.9%). The odds of having sella's bridging in patients with CMMLI were 2.5 times greater than patients with full set of teeth. Age showed a significant (p < 0.001) positive correlation with sella's width only in CMMLI.

Conclusion

Patients with CMMLI tend to have an increased frequency of STB, and decreased sella turcica length.

Aniridia and Axenfeld-Rieger Syndrome: Clinical presentations, molecular genetics and current/emerging therapies

Aniridia and Axenfeld-Rieger Syndrome are related, human ocular disorders that are typically inherited in an autosomal dominant manner. Both result from incorrect development of the eye and have, as their most serious consequences, elevated risk to develop the blinding condition glaucoma. This review will focus on describing the clinical presentations of Aniridia and Axenfeld-Rieger Syndrome as well as the molecular genetics and current and emerging therapies used to treat patients.

Connecting muscle development, birth defects, and evolution: An essential role for muscle connective tissue

Skeletal muscle powers all movement of the vertebrate body and is distributed in multiple regions that have evolved distinct functions. Axial muscles are ancestral muscles essential for support and locomotion of the whole body. The evolution of the head was accompanied by development of cranial muscles essential for eye movement, feeding, vocalization, and facial expression. With the evolution of paired fins and limbs and their associated muscles, vertebrates gained increased locomotor agility, populated the land, and acquired fine motor skills. Finally, unique muscles with specialized functions have evolved in some groups, and the diaphragm which solely evolved in mammals to increase respiratory capacity is one such example. The function of all these muscles requires their integration with the other components of the musculoskeletal system: muscle connective tissue (MCT), tendons, bones as well as nerves and vasculature. MCT is muscle's closest anatomical and functional partner. Not only is MCT critical in the adult for muscle structure and function, but recently MCT in the embryo has been found to be crucial for muscle development. In this review, we examine the important role of the MCT in axial, head, limb, and diaphragm muscles for regulating normal muscle development, discuss how defects in MCT-muscle interactions during development underlie the etiology of a range of birth defects, and explore how changes in MCT development or communication with muscle may have led to the modification and acquisition of new muscles during vertebrate evolution.

Morphology, incidence of bridging, and dimensions of sella turcica in different racial groups

OBJECTIVES

This study was performed to assess the morphological appearance, incidence of bridging, and linear dimensions of the sella turcica (ST) in Bosnian and Iraqi subjects, and to identify associations of sex, age, and racial group with the size of the ST.

METHODS

The digital standardised lateral cephalograms of 360 Bosnian and Iraqi patients (116 female, 64 male; age range 8-28 years) were retrospectively analysed. The following ST-related parameters were analysed on the lateral cephalograms: sella morphology, sella bridging, and sella size. The data were correlated with sex, age, and race.

RESULTS

The ST exhibited a normal morphology in most subjects of both races (86.7%). The frequency of partial bridging was found in 38.9 and 37.2% of Bosnian and Iraqi subjects, respectively. A significant correlation was detected between the length of the ST and sex in both the Bosnian and Iraqi subjects (p < 0.05). A direct correlation was present between patient age and the size of the ST in both races at the 0.01 and 0.001 levels for depth, length, and diameter. When race was compared with sella size, a significant difference was found in the length and depth of the ST (p <  0.001).

CONCLUSIONS

Similarities were found between Bosnian and Iraqi subjects in the morphology, incidence of bridging, and linear dimensions of the ST. Length was the only parameter significantly associated with sex, age, and racial group. These findings could be used as reference standards for studying the ST in both races.

The versatile hippo pathway in oral-maxillofacial development and bone remodeling

The Hippo signaling pathway is implicated in key aspects of cell proliferation, control of organ size, stem cell functions and tumor suppression. Its functions are primarily mediated either through direct effects on transcription factors to influence target gene expression or through crosstalk with other signaling pathways that regulate multiple physiological activities. Studies are revealing Hippo pathway involvement in diverse functions including renewal of intestinal epithelium, promotion of myocardial cell proliferation, cancer suppression, etc. In this review we discuss Hippo pathway signaling in oral-maxillofacial development and bone remodeling under normal and pathological conditions and highlight promising future research directions.

Sella Turcica Bridging As A Predictor Of Class II Malocclusion-An Investigative Study

BACKGROUND

Sella turcica, the bony depression located in sphenoid bone houses and protects the pituitary gland. Formation and development of the sella turcica and teeth share, in common, the involvement of neural crest cells. The anterior part of the sella turcica is believed to develop mainly from neural crest cells, and dental epithelial progenitor cells differentiate through sequential and reciprocal interaction with neural crest-derived mesenchyme. Thus, any structural deviations in the sella, like bridging or roofing, are believed to be related to specific deviations in the facial skeleton and dental anomalies. Until now, there have been no studies concerning the prevalence of sella turcica bridging in skeletal Class II subjects.

OBJECTIVE

The aim of this study was to analyse the prevalence of sella turcica bridging in subjects with class I and class II skeletal types and to check whether sella can be considered as diagnostic marker for skeletal class II malocclusion.

MATERIALS AND METHODS

Lateral cephalometric images of 205 subjects in the age range of 13 to 25 years were retrospectively analysed and classified for the type of skeletal malocclusion and the radiographs were evaluated for the prevalence of bridging of the sella in these subjects.

RESULTS

The results show significance in the prevalence of sella turcica bridging (partial/complete) among subjects with skeletal class II malocclusion.

Accurate prediction of functional, structural, and stability changes in PITX2 mutations using in silico bioinformatics algorithms

Mutations in PITX2 have been implicated in several genetic disorders, particularly Axenfeld-Rieger syndrome. In order to determine the most reliable bioinformatics tools to assess the likely pathogenicity of PITX2 variants, the results of bioinformatics predictions were compared to the impact of variants on PITX2 structure and function. The MutPred, Provean, and PMUT bioinformatic tools were found to have the highest performance in predicting the pathogenicity effects of all 18 characterized missense variants in PITX2, all with sensitivity and specificity >93%. Applying these three programs to assess the likely pathogenicity of 13 previously uncharacterized PITX2 missense variants predicted 12/13 variants as deleterious, except A30V which was predicted as benign variant for all programs. Molecular modeling of the PITX2 homoedomain predicts that of the 31 known PITX2 variants, L54Q, F58L, V83F, V83L, W86C, W86S, and R91P alter PITX2's structure. In contrast, the remaining 24 variants are not predicted to change PITX2's structure. The results of molecular modeling, performed on all the PITX2 missense mutations located in the homeodomain, were compared with the findings of eight protein stability programs. CUPSAT was found to be the most reliable in predicting the effect of missense mutations on PITX2 stability. Our results showed that for PITX2, and likely other members of this homeodomain transcription factor family, MutPred, Provean, PMUT, molecular modeling, and CUPSAT can reliably be used to predict PITX2 missense variants pathogenicity.

A CBCT Investigation of the Association between Sella-Turcica Bridging and Maxillary Palatal Canine Impaction

Objectives

To investigate the association between unilateral/bilateral maxillary canine impaction and sella-turcica bridging using CBCT imaging.

Methods

This retrospective comparative study analyzed 76 CBCT images of the craniofacial complex including sella-turcica. The impacted cuspid group consisted of thirty-eight subjects (7 males, 31 females; mean age, 14.6 ± 3.2 years) diagnosed with unilateral (left n = 14, right n = 11) or bilateral (n = 13) palatal canine impaction. The control group included thirty-eight subjects matched by sex (7 males, 31 females; mean age, 19.5 ± 3.6 years) with no impaction. Multinomial logistic regression analysis was used to determine the association between unilateral/bilateral canine impaction and right and left sella-turcica bridging.

Results

The prevalence of sella-turcica bridging was 59.3% and 50% in the impacted canine and control groups, respectively. Although the odds for unilateral canine impaction were increased in the right and left sella-turcica bridging groups compared to the controls, the difference was not statistically significant. The risk of bilateral impaction was different between the two sides of sella-turcica bridging, but, again, the findings were not statistically significant.

Conclusion

Contrary to previous 2D studies, there is no statistically significant association between unilateral/bilateral palatal canine impaction and sella-turcica bridging when using 3D CBCT.

Sella turcica bridging and ossified carotico-clinoid ligament: Correlation with sex and age

Aim Sella turcica bridging and ossified carotico-clinoid ligament are two variants of the sella turcica, the origin of which is partially unknown. These variations should be properly recognised, as they may hamper the removal of the anterior clinoid process in surgical procedures. Therefore, our aim was to determine the prevalence of these two anatomical variants and to investigate their prevalence according to patient sex and age in a series of maxilla computed tomography scans. Materials and methods We revised 300 computed tomography scans of the head from northern Italian patients, stratified into three age groups (18-40 years, 41-60 years, >60 years): a logistic regression analysis was used to explore an association of sella turcica bridging with age and sex through Matlab software, also including a test for the extracted model ( P < 0.05). Results The mean prevalence of sella turcica bridging and ossified carotico-clinoid ligament were 0.16 ± 0.06 (48/300, 16.0%) and 0.09 ± 0.03 (26/300, 8.7%), respectively. Statistically significant differences according to sex were found neither for sella turcica bridging ( P = 0.345) nor for ossified carotico-clinoid ligament ( P = 0.412). Only sella turcica bridging showed a correlation with age ( P = 0.007). In addition, the two variants were often associated, as patients without sella turcica bridging usually did not show ossified carotico-clinoid ligament ( P < 0.001). Discussion Our results suggest an association between the two variants, and provide a novel contribution to the debate around their origin.

Sella turcica bridging and dental anomalies: is there an association?

BACKGROUND

Sella turcica bridging (STB), or calcification of the interclinoid ligament of sella turcica, has been reported to be associated with some dental anomalies (palatal canine impaction and transposition).

HYPOTHESIS OR AIM

The aim of the study was to find any association between canine impaction, hyperdontia or hypodontia and sellar dimensions or bridging.

DESIGN

Lateral cephalometric radiographs from 78 patients with impacted canines, 68 with dental agenesis and 17 with hyperdontia were collected. Linear dimensions of sella turcica were calculated and compared to those of a control group (47 individuals). A standardize scoring scale was used to quantify the extent of STB from each radiographs.

RESULTS

The frequency of partial and complete calcifications of sella in patients with dental anomalies is increased when compared to controls. STB can influence the interclinoid distance but does not affect other linear dimensions of sella. No statistically significant difference has been found in sellar dimensions and STB expression when evaluating radiographs at different ages.

CONCLUSIONS

STB is frequently found in patients with dental abnormalities.

Glaucoma spectrum and age-related prevalence of individuals with FOXC1 and PITX2 variants

Variation in FOXC1 and PITX2 is associated with Axenfeld-Rieger syndrome, characterised by structural defects of the anterior chamber of the eye and a range of systemic features. Approximately half of all affected individuals will develop glaucoma, but the age at diagnosis and the phenotypic spectrum have not been well defined. As phenotypic heterogeneity is common, we aimed to delineate the age-related penetrance and the full phenotypic spectrum of glaucoma in FOXC1 or PITX2 carriers recruited through a national disease registry. All coding exons of FOXC1 and PITX2 were directly sequenced and multiplex ligation-dependent probe amplification was performed to detect copy number variation. The cohort included 53 individuals from 24 families with disease-associated FOXC1 or PITX2 variants, including one individual diagnosed with primary congenital glaucoma and five with primary open-angle glaucoma. The overall prevalence of glaucoma was 58.5% and was similar for both genes (53.3% for FOXC1 vs 60.9% for PITX2, P=0.59), however, the median age at glaucoma diagnosis was significantly lower in FOXC1 (6.0±13.0 years) compared with PITX2 carriers (18.0±10.6 years, P=0.04). The penetrance at 10 years old was significantly lower in PITX2 than FOXC1 carriers (13.0% vs 42.9%, P=0.03) but became comparable at 25 years old (71.4% vs 57.7%, P=0.38). These findings have important implications for the genetic counselling of families affected by Axenfeld-Rieger syndrome, and also suggest that FOXC1 and PITX2 contribute to the genetic architecture of primary glaucoma subtypes.

Bridging the Gap: Sella Turcica in Unilateral Cleft Lip and Palate Patients

Objectives

The aims of this study were to analyze the prevalence of sella turcica bridging and to measure the size of the sella turcica on profile cephalograms in a homogenous group of surgically repaired unilateral cleft lip and palate (UCLP) patients.

Setting

Tertiary care center.

Design

Retrospective cross-sectional study.

Patients

Preorthodontic lateral cephalometric radiographs of 64 UCLP individuals between the ages of 16 and 29 years along with an equal number of age- and sex-matched skeletal Class I controls.

Main Outcome Measures

The extent of calcification of the interclinoid ligament was quantified (completely calcified, partially calcified, no calcification) and mean values compared. Length, depth, and diameter of the sella turcica were also measured. The results were statistically analyzed using paired t test and Wilcoxon signed ranks test.

Results

Complete sella bridging of both type A (4.6%) and type B (21.7%) was significantly higher in UCLP patients. This has not been reported previously. Partial sella bridging was also higher in cleft patients as evaluated by two methods (42.18%, 39.06%). This study demonstrated a statistically significant decrease in all dimensions of sella turcica in UCLP patients.

Conclusions

The UCLP patients apparently had higher predilection for sella turcica bridging. The dimensions of sella turcica were also seen to be significantly smaller than the control group. Defective proliferation and deviated pathways of neural crest cell migration as well as premature rupture of contact between neuroepithelium and oral ectoderm as postulated causes are discussed.

Indications for a systemic work-up in glaucoma

Most glaucomas are primary in nature. However, many adult and childhood glaucomas are secondary, and they require systemic evaluation to pick up associated systemic disease. Conditions such as nocturnal hypotension and sleep apnea may contribute to glaucomatous progression, whereas neurologic diseases may mimic normal tension glaucoma based on disc appearance. This review highlights those conditions in which a focused systemic work-up can improve glaucoma management and potentially discover life-threatening disease.

Combined pituitary hormone deficiency: current and future status

Over the last two decades, the understanding of the mechanisms involved in pituitary ontogenesis has largely increased. Since the first description of POU1F1 human mutations responsible for a well-defined phenotype without extra-pituitary malformation, several other genetic defects of transcription factors have been reported with variable degrees of phenotype-genotype correlations. However, to date, despite the identification of an increased number of genetic causes of isolated or multiple pituitary deficiencies, the etiology of most (80-90 %) congenital cases of hypopituitarism remains unsolved. Identifying new etiologies is of importance as a post-natal diagnosis to better diagnose and treat the patients (delayed pituitary deficiencies, differential diagnosis of a pituitary mass on MRI, etc.), and as a prenatal diagnosis to decrease the risk of early death (undiagnosed corticotroph deficiency for instance). The aim of this review is to summarize the main etiologies and phenotypes of combined pituitary hormone deficiencies, associated or not with extra-pituitary anomalies, and to suggest how the identification of such etiologies could be improved in the near future.

Dimensions and morphologic variations of sella turcica in type 1 diabetic patients

INTRODUCTION

Some chronic diseases are associated with changes in the morphology of sella turcica, and type 1 diabetes is the most common chronic disease in children and adolescents. Therefore, the aim of this study was to evaluate the size and morphology of sella turcica in patients with type 1 diabetes compared with a healthy control group.

METHODS

The study included 76 type 1 diabetic patients (38 boys, 38 girls; ages, 14.16 ± 2.46 years) and 76 controls (38 boys, 38 girls; ages, 14 ± 2.08 years). The groups were categorized as pubertal and postpubertal according to bone age. The length, height, and diameter of sella turcica were measured. Then the morphology of sella turcica was analyzed and categorized as normal, oblique anterior wall, bridging, double contour of the floor, irregularity in the posterior part of dorsum sellae, or pyramidal shape of the dorsum sellae. All measurements were made on tracings of cephalometric radiographs. Differences between the groups were tested with the Mann-Whitney U test. Categorical data were evaluated with the Fisher exact test, and the Bonferroni correction was made. The significance level was assigned as P <0.05.

RESULTS

There was no statistically significant difference in the dimensions of sella between the diabetic patients (diameter, 12.20 ± 1.49 mm; length, 10.49 ± 1.55 mm; height, 8.07 ± 1.25 mm) and the controls (diameter, 12.45 ± 1.43 mm; length, 10.90 ± 1.73 mm; height, 8.29 ± 1.66 mm). However, diameter and length increased with age in the overall assessment. Length was greater in the postpubertal controls (11.39 ± 1.69 mm) compared with the pubertal controls (10.41 ± 1.64 mm). Diameter was greater in the postpubertal diabetic patients (1.283 ± 1.55 mm) than in the pubertal diabetic patients (11.56 ± 1.12 mm) and was specifically higher in postpubertal boys. Normal sella morphology was less common in general in the diabetic patients, particularly in the diabetic boys and diabetic pubertal boys (P <0.05).

CONCLUSIONS

The measurements concerning sella were similar in the type 1 diabetic and control subjects, but dysmorphologic types were more common in diabetic patients.

Absent sella turcica: a case report and a review of the literature

Absent sella turcica is an extremely rare and dramatic radiographic finding. It may be isolated or occur in the presence of other anomalies, often involving the adenohypophysis. Our evaluation of a female infant with multiple anomalies including absence of the sella turcica, a normal pituitary in the craniopharyngeal canal, normal pituitary function, choanal atresia and anomalies of the appendiceal skeleton prompted a review of the occurrence and biology of an absent sella turcica.

Two cases of axenfeld-rieger syndrome, report of the complex pathology and treatment

The purpose of this case report is to report the orthodontic surgical treatment and subsequent dental rehabilitation in two patients with Axenfeld-Rieger syndrome. Axenfeld-Rieger syndrome is a rare autosomal dominant condition characterized by ocular, dental, craniofacial, and periumbilical abnormalities. The treatment of two patients with various anomalies in Axenfeld-Rieger syndrome is described and discussed. Early recognition of the syndrome and referral during childhood to a specialized oral and maxillofacial surgery, special dental care, and orthodontic unit provide the optimal starting point for this complex treatment.

Magnetic resonance imaging findings in Axenfeld-Rieger syndrome

Axenfeld–Rieger syndrome (ARS) is a genetic disorder representing a disease spectrum resulting from neural crest cell maldevelopment. Glaucoma is a common complication from the incomplete formation of the iridocorneal angle structures. Neural crest cells also form structures of the forebrain and pituitary gland, dental papillae, aortic arch walls, genitalia, and long bones; therefore, patients with ARS manifest a wide range of systemic findings. To our knowledge, detailed magnetic resonance imaging findings have not been previously reported. We report a case of a 19-month-old Indian male diagnosed with ARS with emphasis on magnetic resonance imaging findings of the globes, brain, teeth, and skull base.

PITX2 AND PITX1 regulate thyrotroph function and response to hypothyroidism

Pitx2 is a homeodomain transcription factor required in a dose-dependent manner for the development of multiple organs. Pitx2-null homozygotes (Pitx2(-/-)) have severe pituitary hypoplasia, whereas mice with reduced-function alleles (Pitx2(neo/neo)) exhibit modest hypoplasia and reduction in the developing gonadotroph and Pou1f1 lineages. PITX2 is expressed broadly in Rathke's pouch and the fetal pituitary gland. It predominates in adult thyrotrophs and gonadotrophs, although it is not necessary for gonadotroph function. To test the role of PITX2 in thyrotroph function, we developed thyrotroph-specific cre transgenic mice, Tg(Tshb-cre) with a recombineered Tshb bacterial artificial chromosome that ablates floxed genes in differentiated pituitary thyrotrophs. We used the best Tg(Tshb-Cre) strain to generate thyrotroph-specific Pitx2-deficient offspring, Pitx2(flox/-;)Tg(Tshb-cre). Double immunohistochemistry confirmed Pitx2 deletion. Pitx2(flox/-);Tg(Tshb-cre) mice have a modest weight decrease. The thyroid glands are smaller, although circulating T(4) and TSH levels are in the normal range. The pituitary levels of Pitx1 transcripts are significantly increased, suggesting a compensatory mechanism. Hypothyroidism induced by low-iodine diet and oral propylthiouracil revealed a blunted TSH response in Pitx2(flox/-);Tg(Tshb-cre) mice. Pitx1 transcripts increased significantly in control mice with induced hypothyroidism, but they remained unchanged in Pitx2(flox/-);Tg(Tshb-cre) mice, possibly because Pitx1 levels were already maximally elevated in untreated mutants. These results suggest that PITX2 and PITX1 have overlapping roles in thyrotroph function and response to hypothyroidism. The novel cre transgene that we report will be useful for studying the function of other genes in thyrotrophs.

The role of homeodomain transcription factors in heritable pituitary disease

The anterior pituitary gland secretes hormones that regulate developmental and physiological processes, including growth, the stress response, metabolic status, reproduction and lactation. During embryogenesis, cellular determination and differentiation events establish specialized hormone-secreting cell types within the anterior pituitary gland. These developmental decisions are mediated in part by the actions of a cascade of transcription factors, many of which belong to the homeodomain class of DNA-binding proteins. The discovery of some of these regulatory proteins has facilitated genetic analyses of patients with hormone deficiencies. The findings of these studies reveal that congenital defects-ranging from isolated hormone deficiencies to combined pituitary hormone deficiency syndromes-are sometimes associated with mutations in the genes encoding pituitary-acting developmental transcription factors. The phenotypes of affected individuals and animal models have together provided useful insights into the biology of these transcription factors and have suggested new hypotheses for testing in the basic science laboratory. Here, we summarize the gene regulatory pathways that control anterior pituitary development, with emphasis on the role of the homeodomain transcription factors in normal pituitary organogenesis and heritable pituitary disease.

Potential novel mechanism for Axenfeld-Rieger syndrome: deletion of a distant region containing regulatory elements of PITX2

PURPOSE

Mutations in PITX2 are associated with Axenfeld-Rieger syndrome (ARS), which involves ocular, dental, and umbilical abnormalities. Identification of cis-regulatory elements of PITX2 is important to better understand the mechanisms of disease.

METHODS

Conserved noncoding elements surrounding PITX2/pitx2 were identified and examined through transgenic analysis in zebrafish; expression pattern was studied by in situ hybridization. Patient samples were screened for deletion/duplication of the PITX2 upstream region using arrays and probes.

RESULTS

Zebrafish pitx2 demonstrates conserved expression during ocular and craniofacial development. Thirteen conserved noncoding sequences positioned within a gene desert as far as 1.1 Mb upstream of the human PITX2 gene were identified; 11 have enhancer activities consistent with pitx2 expression. Ten elements mediated expression in the developing brain, four regions were active during eye formation, and two sequences were associated with craniofacial expression. One region, CE4, located approximately 111 kb upstream of PITX2, directed a complex pattern including expression in the developing eye and craniofacial region, the classic sites affected in ARS. Screening of ARS patients identified an approximately 7600-kb deletion that began 106 to 108 kb upstream of the PITX2 gene, leaving PITX2 intact while removing regulatory elements CE4 to CE13.

CONCLUSIONS

These data suggest the presence of a complex distant regulatory matrix within the gene desert located upstream of PITX2 with an essential role in its activity and provides a possible mechanism for the previous reports of ARS in patients with balanced translocations involving the 4q25 region upstream of PITX2 and the current patient with an upstream deletion.

Dental and Craniofacial Anomalies Associated with Axenfeld-Rieger Syndrome with PITX2 Mutation

Axenfeld-Rieger syndrome (ARS) (OMIM Nr.: 180500) is a rare autosomal dominant disorder (1  :  200000) with genetic and morphologic variability. Glaucoma is associated in 50% of the patients. Craniofacial and dental anomalies are frequently reported with ARS. The present study was designed as a multidisciplinary analysis of orthodontic, ophthalmologic, and genotypical features. A three-generation pedigree was ascertained through a family with ARS. Clinically, radiographic and genetic analyses were performed. Despite an identical genotype in all patients, the phenotype varies in expressivity of craniofacial and dental morphology. Screening for PITX2 and FOXC1 mutations by direct DNA-sequencing revealed a P64L missense mutation in PITX2 in all family members, supporting earlier reports that PITX2 is an essential factor in morphogenesis of teeth and craniofacial skeleton. Despite the fact that the family members had identical mutations, morphologic differences were evident. The concomitant occurrence of rare dental and craniofacial anomalies may be early diagnostic indications of ARS. Early detection of ARS and elevated intraocular pressure (IOP) helps to prevent visual field loss.

Genetic forms of hypopituitarism and their manifestation in the neonatal period

The anterior pituitary gland is a central regulator of growth, reproduction and homeostasis. The development of the pituitary gland depends on the sequential temporal and spatial expression of transcription factors and signalling molecules. Naturally occurring and transgenic murine models have demonstrated a role for many of these molecules in the aetiology of congenital hypopituitarism. These include the transcription factors HESX1, PROP1, POU1F1, LHX3, LHX4, PITX1, PITX2, OTX2, SOX2 and SOX3. Mutations in any of the genes involved in pituitary development may result in congenital hypopituitarism, which manifests as the deficiency in one or more pituitary hormones. The phenotype can be highly variable and may consist of isolated hypopituitarism, or more complex disorders such as septo-optic dysplasia (SOD) and holoprosencephaly. Neonates with congenital hypopituitarism may present with non-specific symptoms, with or without associated developmental defects such as ocular, midline and genital abnormalities. Alternatively, they may be initially asymptomatic but at risk of developing pituitary hormone deficiencies over time. The overall incidence of mutations in known transcription factors in patients with hypopituitarism is low, indicating that many genes remain to be identified. Their characterization will further elucidate the pathogenesis of this complex condition and will shed light on normal pituitary development.

Bridging of the sella turcica in skeletal Class III subjects

Several investigations have analysed the frequency of sella turcica anomalies in patients with severe craniofacial deviations. Until now, there have been no studies concerning the prevalence of sella turcica bridging in homogenous groups of patients. Therefore, the aims of this controlled study were to analyse the prevalence of sella turcica bridging and measure the size of the sella turcica in two well-defined groups of Caucasian individuals. In a multicentre retrospective study, 400 pre-treatment lateral cephalograms of adult patients (over 17 years of age) with a skeletal Class III (n = 250, 132 females and 118 males) or a skeletal Class I (n = 150, 94 females and 56 males) malocclusion were analysed. The morphology, length, depth, and diameter of the sella turcica were investigated. For statistical analysis, chi-square and t-tests were used. Skeletal Class III patients presented a significantly higher rate of sella turcica bridging, 16.8 per cent (P = 0.031), in comparison with skeletal Class I patients, whose rate was 9.4 per cent. No differences between females and males were detected for the length, depth, and diameter of the sella turcica. Bridging of the sella turcica could be seen radiographically in skeletal Class III subjects.