Crouzon's syndrome: A review of literature and case report

Radiological Diagnosis of Crouzon Syndrome: A Case Study

Crouzon syndrome, distinguished by a classic trio of an atypical skull structure, distinctive facial features, and protruding eyes, ranks among the most prevalent types of craniofacial dysostosis. Therefore, patients presenting with dental abnormalities are under-reported in medical literature despite the developmental neurological defects. We report a rare case of Crouzon syndrome in a four-year-old girl who had forward displacement of the lower jaw, bulging eyes, undeveloped upper jaw, and dental abnormalities. She was evaluated with cranial computed tomography with three-dimensional reconstruction; genetic studies confirmed the findings.

Crouzon Syndrome Spanning Three Generations: Advances in the Treatment of Syndromic Midface Deficiency

Background

Crouzon syndrome is an autosomal dominant genetic disorder characterized by craniosynostosis, midface retrusion, and exophthalmos. Over the past century, the treatment of craniofacial disorders like Crouzon syndrome has evolved significantly.

Methods

An institutional review board-approved retrospective study was conducted to ascertain the treatment of three individuals with Crouzon syndrome from one family, complemented with a series of literature searches to examine the evolution of craniofacial surgical history.

Results

Dr. David Williams Cheever developed the Le Fort I level to correct malocclusion, maxillomandibular malformations, and midface hypoplasia. Later, Dr. Paul Tessier introduced the Le Fort II and III osteotomies to treat syndromic midface hypoplasia. In 1978, Dr. Fernando Ortiz-Monasterio and Dr. Antonio Fuente del Campo published the first series of monobloc osteotomies, allowing for simultaneous correction of supraorbital and midface malformations, although complicated by blood loss and high infection rates. In 1992, McCarthy et al introduced the concept of gradual distraction to the craniofacial skeleton. In 1995, Polley et al performed the first monobloc advancement using external distraction. Subsequently, in 1997, Polley and Figueroa introduced a rigid external distraction device with multiple vector control to manage severe cleft maxillary hypoplasia. The technique was further refined and applied to treat syndromic midface hypoplasia, reducing complication rates. Currently, either external or internal distraction approaches are used to safely treat this challenging group of patients.

Conclusion

The treatment of syndromic midface deficiency has significantly evolved over the past 50 years, as evidenced by this report of three generations of Crouzon syndrome.

Crouzon syndrome with acanthosis nigricans: A case report and literature review

Crouzon’s syndrome with acanthosis nigricans is an autosomal dominant disease, with typical features of classic Crouzon craniosynostosis, verrucous hyperplasia, and hyperpigmentation of the skin. While several mutations in FGFR2 cause classic Crouzon syndrome, Crouzon syndrome with acanthosis nigricans results from a point mutation in the fibroblast growth factor receptor 3 gene (FGFR3). We report an 8-year-old Vietnamese girl diagnosed with Crouzon syndrome with acanthosis nigricans, showing typical clinical features, including a crouzonoid face and dark plaques on skin. Genetic testing showed a missense variation in FGFR3, associated with Crouzon syndrome with acanthosis nigricans. Following diagnosis, we treated acanthosis nigricans with 10% urea cream. This case study and literature review discusses the cutaneous manifestations and dermatological treatments, while demonstrating the importance of clinical examination and evaluation of the patient’s medical history during diagnosis. Our findings contribute to the global pool of data, providing practical insights into the manifestations of Crouzon syndrome.

Crouzon syndrome in a fraternal twin: A case report and review of the literature

BACKGROUND

Crouzon syndrome (CS; OMIM 123500) is an autosomal dominant inherited craniofacial disorder caused by mutations in the fibroblast growth factor receptor 2 (FGFR2) gene. CS is characterized by craniofacial dysostosis, exophthalmos, and facial anomalies with hypoplastic maxilla and relative mandibular prognathism.

CASE SUMMARY

Our report involves a 6-year-old fraternal twin boy with many caries in the oral cavity who presented with characteristic features of CS based on clinical and radiographic examinations along with Sanger sequencing. The fraternal girl did not show any abnormalities indicating CS. Carious teeth and poor oral hygiene were managed promptly through administering appropriate behavior guidance, orthodontic treatment was planned, and preventive procedures were described.

CONCLUSION

CS could occur in a fraternal twin caused by a de novo mutation of the FGFR2 gene. Oral hygiene instruction, preventive programs on oral hygiene, orthodontic treatment, and maxillary osteotomy were required for treatment.

The need to belong: Subjective experiences of living with craniofacial conditions and undergoing appearance-altering surgery

The purpose of this study was to better understand how individuals with craniofacial conditions experience living with visible differences and make sense of appearance-altering surgery. We conducted semi-structured qualitative interviews with 11 adults with Goldenhar or Crouzon syndrome. Interviews were analysed using a hermeneutic-phenomenological approach to thematic analysis. Our analysis revealed the following overarching theme, To see myself as other people see me, which encompassed three main themes: a) Striving to fit in, b) Altering the way I look and c) Support from family and friends. The participants' sense of their own appearance seemed to be connected to how they perceived others to evaluate their appearance. All had experienced negative reactions from others. They experienced themselves as different and had a desire to belong. All participants had undergone appearance-altering surgery, hoping that by changing appearance, they would reduce negative reactions and feel more connected to and accepted by other people. The process of undergoing appearance-changing surgery was experienced as challenging, and participants wished for a dialogue with surgeons which included psychological and emotional aspects of changing appearance. A better understanding of how to strengthen positive identity processes and feelings of belongingness should be a key focus of future research.

Imaging diagnosis of Crouzon syndrome in two cases confirmed on genetic studies - with a brief review

Crouzon syndrome is the most common form of craniofacial dysostosis, characterised by a classical triad of abnormal skull shape, abnormal facies, and exophthalmos. The clinically overt dental abnormalities in these patients, distracts clinicians from the developmental neurological defects and therefore this entity remains relatively under - highlighted in radiology literature. We report and highlight the role of imaging in diagnosis of Crouzon syndrome in two patients, and discuss the relevant differential diagnosis. Moreover, our report is among the few Indian studies in which Crouzon syndrome was confirmed by genetic studies. The classical clinical triad of Crouzon syndrome was observed in both patients. The skull radiographs and cranial CT with 3D reconstruction VRT (Volume rendered technique), revealed characteristic radiological features. Genetic studies reconfirmed the clinical and radiological diagnosis of Crouzon syndrome, in both patients.

Transcriptome Analysis Identifies Multifaceted Regulatory Mechanisms Dictating a Genetic Switch from Neuronal Network Establishment to Maintenance During Postnatal Prefrontal Cortex Development

The prefrontal cortex (PFC) is one of the latest brain regions to mature, which allows the acquisition of complex cognitive abilities through experience. To unravel the underlying gene expression changes during postnatal development, we performed RNA-sequencing (RNA-seq) in the rat medial PFC (mPFC) at five developmental time points from infancy to adulthood, and analyzed the differential expression of protein-coding genes, long intergenic noncoding RNAs (lincRNAs), and alternative exons. We showed that most expression changes occur in infancy, and that the number of differentially expressed genes reduces toward adulthood. We observed 137 differentially expressed lincRNAs and 796 genes showing alternative exon usage during postnatal development. Importantly, we detected a genetic switch from neuronal network establishment in infancy to maintenance of neural networks in adulthood based on gene expression dynamics, involving changes in protein-coding and lincRNA gene expression as well as alternative exon usage. Our gene expression datasets provide insights into the multifaceted transcriptional regulation of the developing PFC. They can be used to study the basic developmental processes of the mPFC and to understand the mechanisms of neurodevelopmental and neuropsychiatric disorders. Our study provides an important contribution to the ongoing efforts to complete the "brain map", and to the understanding of PFC development.

Le Fort II Osteotomy and Modified Technique Presentation

INTRODUCTION

The LeFort II osteotomy has a specific number of indications, thus this is true, there is less experience with the technique. The authors present a modification to the technique and extensive step-by-step procedure explanation in order to share their experience for making a safe surgery.

MATERIAL AND METHODS

A clinical report is presented of a nonsyndromatic patient with nasomaxillary hypoplasia, in which the authors make an LeFort II osteotomy with circumvestibular, transcaruncular, and "W"-shaped approaches, with minimal scar showing, in order to offer better aesthetic outcomes as well as functional and skeletal.

RESULTS

Patient presenting with an optimal postoperative clinical and skeletal results. Cephalometic measurments in normal ranges. Obtaining during the process of the surgery, description the surgery, and potential complications.

CONCLUSION

Using the Le Fort II osteotomy in nonsyndromic nasomaxillary hypoplasia is a helpful and left away technique, because of its complexity. The authors give a step-by-step detailed description of the surgical technique with perioperative management. In summary, the steps provided give unique information about this reproducible and aesthetic technique.

Extensive phenotyping of the orofacial and dental complex in Crouzon syndrome

OBJECTIVES

Fibroblast growth factor receptor 2 (FGFR2) ^C342Y/+ mutation is a known cause of Crouzon syndrome that is characterised by craniosynostosis and midfacial hypoplasia. Our aim was to conduct extensive phenotyping of the maxillary, mandibular and dental morphology associated with this mutation.

MATERIALS AND METHODS

Morphometric data were obtained from 40 mice, representing two genotypes (Crouzon and wild-type) and two sexes (males and females) (n=10 in each group). Dental analysis further categorised the first molars into the two jaws (maxillary and mandibular) (n=20 in each group). Maxillary, mandibular and dental morphology was compared by analysing 23 linear landmark-based dimensions in three-dimensional micro-computed tomography reconstructions.

RESULTS

Compared with wild-type, Crouzon (FGFR2^C342Y/+) maxillae were significantly shorter in maximum height, anterior and posterior lengths and middle width, but larger in posterior width (p<0.05 for height; p<0.001 for other comparisons). In the Crouzon mandible, the ascending and descending heights, effective and mandibular lengths, and intercoronoid and intercondylar widths were significantly shorter, whereas intergonial width was larger (p<0.01 for intercondylar width; p<0.001 for other comparisons). Crouzon teeth were significantly smaller mesiodistally, but larger in crown height (p<0.001 for each comparison). All Crouzon mice presented with bifid mandibular condyles and a quarter presented with expansive bone lesions in the mandibular incisor alveolus.

CONCLUSIONS

Our findings of hypoplasia in all three planes in Crouzon maxillae and mandibles, together with the presence of bifid mandibular condyles and expansive bone lesions, may be relevant to maxillofacial surgery and orthodontics. Beyond skeletal effects, the FGFR2^C342Y/+ mutation is now implicated in affecting tooth development. This study's skeletal phenomics data also provides baseline data against which the effect of various treatments can now be assessed.

Exophthalmos associated to orbital zygomatic mucocele and complex maxillary malformation in a puppy

A case of exophthalmos due to zygomatic mucocele in a puppy with ipsilateral segmental maxillary atrophy is reported. A 7-month-old, mixed breed, male dog suffered the sudden-onset of unilateral painful exophthalmos and a gradual swelling of the right temporal region. A compressing, right retrobulbar mass was observed by ultrasound. Computed tomography revealed a large multiloculated cyst-like lesion of the right zygomatic gland projecting into the orbital space, thus displacing the eyeball. The ipsilateral molar part of the maxillary bone was underdeveloped, besides showing crowded, abnormal, multiple, unerupted maxillary molar teeth in the caudal maxillary region. Modified lateral orbitotomy and a selective caudal maxillary bone access were performed. The cyst-like lesion was removed and the zygomatic gland and the wall was collected for histology, which confirmed the mucocele. Clinical and imaging examinations six months after surgery showed neither recurrence of the mucocele nor ocular abnormalities. A possible common pathogenic mechanism involving these two conditions could be hypothesized.

Clinical characteristics of Crouzon syndrome

Crouzon syndrome (CS) is an genetic disorder with autosomal dominant inheritance caused by mutation of the gene for fibroblast growth factor receptor 2 (FGFR2) was described as one of the varieties of craniosynostosis. In this presented case, premature closure of the sutures had caused restricted skull growth and lack of space for the growing brain resulted to shallowed eyes and cranial and ophthalmic deformities and impairment in tooth development. Management of a patient of CS has two components. First is the release of prematurely fused sutures based on evidence of raised intracranial pressure. Surgery is mainly carried out early after 3–6 months. Second is the craniofacial reconstructive surgery including advancement of the maxilla and frontonasal complex; and other surgeries depending upon the deformities. An increased intracranial pressure impairs brain development and can lead to mental retardation. Because of the delayed diagnosis and treatment in this case, visual and hearing loses and decreased mental capacity and mild retardation.

Molecular analysis of FGFR 2 and associated clinical observations in two Chinese families with Crouzon syndrome

Crouzon syndrome, a dominantly inherited disorder and the most common type of craniosynostosis syndrome, is caused by mutations in the fibroblast growth factor receptor 2 (FGFR 2) gene, and characterized by craniosynostosis, shallow orbits, ocular proptosis, midface hypoplasia and a curved, beak-like nose. The purpose of the present study was to investigate the fibroblast growth factor receptor 2 (FGFR 2) gene in two Chinese families with Crouzon syndrome and to characterize the associated clinical features. Two families underwent complete ophthalmic examination, and three patients in two families were diagnosed with Crouzon syndrome. Genomic DNA was extracted from leukocytes of peripheral blood samples, which were collected from the family members and 200 unrelated control subjects from the same population. Exons 8 and 10 of the FGFR 2 gene were amplified using polymerase chain reaction analysis and were directly sequenced. Ophthalmic examinations, including best-corrected visual acuity, slit-lamp examination, fundus examination and Computerized Tomography scans, and physical examinations were performed to exclude systemic diseases. These patients were affected with shallow orbits and ocular proptosis, accompanied by midface hypoplasia, craniosynostosis, strabismus or papilloedema, with clinically normal hands and feet. A heterozygous FGFR 2 missense mutation, c.811-812insGAG (p.273insGlu) in exon 8 was identified in the affected individual, but not in the unaffected family members or the normal control individuals in family 1. In family 2, another heterozygous FGFR 2 missense mutation, c.842A>G (P.Tyr281Cys or Y281C), in exon 8 was identified in the affected boy and his mother, but not in the unaffected family members or the normal control individuals. Although FGFR 2 gene mutations and polymorphisms have been reported in various ethnic groups, particularly in the area of osteology, the present study reported for the first time, to the best of our knowledge, the identification of two novel FGFR 2 gene mutations in Chinese patients with Crouzon syndrome.

Molecular underpinnings of prefrontal cortex development in rodents provide insights into the etiology of neurodevelopmental disorders

The prefrontal cortex (PFC), seat of the highest-order cognitive functions, constitutes a conglomerate of highly specialized brain areas and has been implicated to have a role in the onset and installation of various neurodevelopmental disorders. The development of a properly functioning PFC is directed by transcription factors, guidance cues and other regulatory molecules and requires the intricate and temporal orchestration of a number of developmental processes. Disturbance or failure of any of these processes causing neurodevelopmental abnormalities within the PFC may contribute to several of the cognitive deficits seen in patients with neurodevelopmental disorders. In this review, we elaborate on the specific processes underlying prefrontal development, such as induction and patterning of the prefrontal area, proliferation, migration and axonal guidance of medial prefrontal progenitors, and their eventual efferent and afferent connections. We furthermore integrate for the first time the available knowledge from genome-wide studies that have revealed genes linked to neurodevelopmental disorders with experimental molecular evidence in rodents. The integrated data suggest that the pathogenic variants in the neurodevelopmental disorder-associated genes induce prefrontal cytoarchitectonical impairments. This enhances our understanding of the molecular mechanisms of prefrontal (mis)development underlying the four major neurodevelopmental disorders in humans, that is, intellectual disability, autism spectrum disorders, attention deficit hyperactivity disorder and schizophrenia, and may thus provide clues for the development of novel therapies.

Functions of Fibroblast Growth Factor Receptors in cancer defined by novel translocations and mutations

The four receptor tyrosine kinases (RTKs) within the family of Fibroblast Growth Factor Receptors (FGFRs) are critical for normal development but also play an enormous role in oncogenesis. Mutations and/or abnormal expression often lead to constitutive dimerization and kinase activation of FGFRs, and represent the primary mechanism for aberrant signaling. Sequencing of human tumors has revealed a plethora of somatic mutations in FGFRs that are frequently identical to germline mutations in developmental syndromes, and has also identified novel FGFR fusion proteins arising from chromosomal rearrangements that contribute to malignancy. This review details approximately 200 specific point mutations in FGFRs and 40 different fusion proteins created by translocations involving FGFRs that have been identified in human cancer. This review discusses the effects of these genetic alterations on downstream signaling cascades, and the challenge of drug resistance in cancer treatment with antagonists of FGFRs.

Crouzon syndrome: clinico-radiological illustration of a case

Crouzon syndrome, also called craniofacial dysostosis, is an autosomal dominant disorder with complete penetrance and variable expressivity. Described by a French neurosurgeon in 1912, it is a rare genetic disorder characterized by premature closure of cranial sutures, midfacial hypoplasia, and orbital defects. Here, we report a case of this rare entity. The patient presented with brachycephaly, maxillary hypoplasia, exophthalmos, mandibular prognathism, along with dental and orbital abnormalities.