Ocular abnormalities in Apert syndrome: genotype/phenotype correlations with fibroblast growth factor receptor type 2 mutations

Numerical Aberrations of the Extraocular Muscles and the Levator Palpebrae Superioris: An Anatomical and Clinical Insight

PURPOSE

To comprehensively review the literature about numerical aberrations of the orbital muscles of ocular motility (here referred to as extraocular muscles [EOMs]) and the levator palpebrae superioris (LPS).

METHODS

The authors summarize the embryologic bases and the possible etiopathogenetic causes of numerical aberrations of the EOMs and the LPS and organize these lesions into several broad categories. The clinical and radiologic diagnostic challenges are discussed.

RESULTS

Numerical aberrations of the EOMs include: 1) the complete absence of EOMs, 2) duplication of an entire EOM, 3) the presence of muscle bands that connect 2 EOMs, and 4) minor morphological variations such as bifid muscles (partial splitting of the muscle). Some cases may defy categorization into any of the above or may resemble atavistic remnants of the retractor bulbi muscle. Broadly speaking, numerical aberrations of the LPS generally fall into the same categories although the LPS has several peculiar numerical anomalies of its own.

CONCLUSIONS

Although numerical EOM and LPS variations are relatively rare and of little clinical significance, raising awareness about their presence is a fundamental clinical keystone not just for the strabismus surgeon but for the orbital surgeon as well. During orbital surgery, this may spare the surgeon from pursuing an orbital witch hunt for these benign innocuous accessory orbital structures that were accidentally discovered by the radiologist and misinterpreted as sinister etiologies. For the strabismus surgeon, the failure to identify them may result in an unfavorable surgical outcome if these structures are missed because of a lack of awareness despite being responsible for generating complex strabismus patterns or having a restrictive potential of their own.

AI-based diagnosis and phenotype - Genotype correlations in syndromic craniosynostoses

Apert (AS), Crouzon (CS), Muenke (MS), Pfeiffer (PS), and Saethre Chotzen (SCS) are among the most frequently diagnosed syndromic craniosynostoses. The aims of this study were (1) to train an innovative model using artificial intelligence (AI)-based methods on two-dimensional facial frontal, lateral, and external ear photographs to assist diagnosis for syndromic craniosynostoses vs controls, and (2) to screen for genotype/phenotype correlations in AS, CS, and PS. We included retrospectively and prospectively, from 1979 to 2023, all frontal and lateral pictures of patients genetically diagnosed with AS, CS, MS, PS and SCS syndromes. After a deep learning-based preprocessing, we extracted geometric and textural features and used XGboost (eXtreme Gradient Boosting) to classify patients. The model was tested on an independent international validation set of genetically confirmed patients and non-syndromic controls. Between 1979 and 2023, we included 2228 frontal and lateral facial photographs corresponding to 541 patients. In all, 70.2% [0.593-0.797] (p < 0.001) of patients in the validation set were correctly diagnosed. Genotypes linked to a splice donor site of FGFR2 in Crouzon-Pfeiffer syndrome (CPS) caused a milder phenotype in CPS. Here we report a new method for the automatic detection of syndromic craniosynostoses using AI.

Lacrimal Obstruction in Craniosynostosis: Anatomical and Genetic Risk Factors

PURPOSE

To investigate whether patients with craniosynostosis exhibit higher rates of nasolacrimal duct obstruction (NLDO) and to explore potential risk factors.

METHODS

Retrospective review including all craniosynostosis patients treated at both the Divisions of Ophthalmology and Plastic, Reconstructive, and Oral Surgery at The Children's Hospital of Philadelphia between 2009 and 2020 was conducted. Synostosis characteristics, lacrimal disorders, and genetic data were collected. Main outcome measures were the rate of NLDO and associations with anatomical and syndromic/genetic risk factors.

RESULTS

The total of 767 participants had a mean age of 2.8 ± 3.8 years, 465 (60.6%) were males, 485 (63.2%) had no syndromic association; 631 (82.3%) had one major suture involved, 128 (17%) had involvement of 2 to 4 major sutures, and 429 (55.9%) underwent craniofacial surgery. Forty-eight (6.2%) patients had NLDO, which more prevalent in the genetic/syndromic group (11.0% vs. 3.5%, respectively, p < 0.001), with the highest prevalence observed in patients with Apert syndrome (n = 4, 30.8%). The genetic variants most associated with NLDO were EFNB1 (n = 1, 100%) and FGFR2 (n = 6, 19.4%). There was no association between NLDO and the number or types of sutures involved or a history of craniofacial surgery.

CONCLUSIONS

Nasolacrimal duct obstruction is more common in patients with craniosynostosis compared to the general population. Having a putative syndrome or a putative genetic variant and female sex were risk factors for NLDO. Ophthalmic evaluations for all craniosynostosis patients and careful assessments of any symptoms of tearing are recommended.

Orbital and Eyelid Characteristics, Strabismus, and Intracranial Pressure Control in Apert Children Treated by Endoscopic Strip Craniectomy versus Fronto-Orbital Advancement

Apert syndrome is characterized by eyelid dysmorphology, V-pattern strabismus, extraocular muscle excyclorotation, and elevated intracranial pressure (ICP). We compare eyelid characteristics, severity of V-pattern strabismus, rectus muscle excyclorotation, and ICP control in Apert syndrome patients initially treated by endoscopic strip craniectomy (ESC) at about 4 months of age versus fronto-orbital advancement (FOA) performed about 1 year of age.

Methods

Twenty-five patients treated at Boston Children's Hospital met inclusion criteria for this retrospective cohort study. Primary outcomes were magnitude of palpebral fissure downslanting at 1, 3, and 5 years of age, severity of V-pattern strabismus, rectus muscle excyclorotation, and interventions to control ICP.

Results

Before craniofacial repair and through 1 year of age, none of the studied parameters differed for FOA versus ESC treated patients. Palpebral fissure downslanting became statistically greater for those treated by FOA by 3 (P < 0.001) and 5 years of age (P = 0.001). Likewise, severity of palpebral fissure downslanting correlated with severity of V-pattern strabismus at 3 (P = 0.004) and 5 (P = 0.002) years of age. Palpebral fissure downslanting and rectus muscle excyclorotation were typically coexistent (P = 0.053). Secondary interventions to control ICP were required in four of 14 patients treated by ESC (primarily FOA) and in two of 11 patients initially treated by FOA (primarily third ventriculostomy) (P = 0.661).

Conclusions

Apert patients initially treated by ESC had less severe palpebral fissure downslanting and V-pattern strabismus, normalizing their appearance. Thirty percent initially treated by ESC required secondary FOA to control ICP.

Visual outcomes in children with syndromic craniosynostosis: a review of 165 cases

OBJECTIVE

To determine visual outcomes and prevalence of amblyogenic risk factors in children with Apert, Crouzon, Pfeiffer and Saethre-Chotzen syndromes.

METHODS

We conducted a single-centre, retrospective chart review of patients assessed at our unit between October 2000 and May 2017. Our outcome measures were as follows: age at first and last examination, refraction, horizontal ocular alignment, alphabet pattern deviations, anterior segment appearance, fundus examination findings, visual evoked potentials (VEPs) and genetics. The study's primary endpoint was the proportion of children achieving best-corrected visual acuity (BCVA) ≥ 6/12 in the better eye at final visit, as per UK driving standards.

RESULTS

165 patients were included in this study. Breakdown of diagnoses was as follows: Crouzon (n = 60), Apert (n = 57), Pfeiffer (n = 14) and Saethre-Chotzen (n = 34). 98 patients were male. Of 133 patients with full BCVA data available, 76.7% achieved BCVA ≥ 6/12 in the better eye. Of 122 patients, anisometropia >1.00 dioptre sphere (DS) affected 18.9% and astigmatism ≥1.00DS in at least one eye affected 67.2%. Of 246 eyes, 48.4% had oblique astigmatism. Of 165 patients, 60 had exotropia and 12 had esotropia. 48 of 99 patients demonstrated 'V' pattern. On multivariable logistic regression, nystagmus (p = 0.009) and ON involvement (p = 0.001) were associated with decreased vision in the worse eye. Normal VEPs were associated with better BCVA (p = 0.036).

CONCLUSION

There was a high prevalence of amblyogenic factors, however, the majority achieved BCVA ≥ 6/12 in their better eye. Optic neuropathy and nystagmus had the most significant impact on vision. VEPs can help the in overall assessment of visual function.

Hearing, Speech, Language, and Communicative Participation in Patients With Apert Syndrome: Analysis of Correlation With Fibroblast Growth Factor Receptor 2 Mutation

Apert syndrome (AS) is caused by the heterozygous presence of 1 of 2 specific missense mutations of the fibroblast growth factor receptor 2 (FGFR2) gene. The 2 adjacent substitutions, designated p.Ser252Trp (S252W) and p.Pro253Arg (P253R), account for more than 98% of cases. Previous research has identified elevated hearing difficulties and incidence of cleft palate in this population. However, the influence of FGFR2 genotype on the speech, language, and communicative participation of children with AS has yet to be examined.

METHODS

A retrospective case note analysis was completed for all patients with a genetically-confirmed Apert mutation who attended the Oxford Craniofacial Unit over a 43-year period (1978-2020). Medical records were analyzed for speech, language, hearing, and communication data in detail. The therapy outcome measures, based on the World Health Organization International Classification of Functioning, Disability, and Health was used to classify patient's communicative participation.

RESULTS

The authors identified 55 AS patients with genetically-confirmed mutation of the FGFR2 gene. One patient with a S252F mutation was excluded. There were 31 patients with the S252W mutation (male = 14; female = 17), age range of last hearing assessment (1-18 years), 64% (18/28) of patients had a cleft palate (including bifid uvula), 15 patients had conductive hearing loss, 1 patient had mixed hearing loss, 18 had otitis media with effusion (4 of whom had a cleft palate); 88% (21/24) of patients had receptive language difficulties, 88% (22/25) of patients had expressive language difficulties, 96% (27/28) of patients had a speech sound disorder. There were 23 patients with the P253R mutation (male = 13; female = 10); age range of last hearing assessment (1-13 years), 35% (8/23) patients had a cleft palate (including bifid uvula), 14 patients had a conductive hearing loss, 17 had otitis media with effusion (2 of whom had a cleft palate). Results indicated that 85% (17/20) of patients had receptive language difficulties, 80% (16/20) had expressive language difficulties, 100% (21/21) had a speech sound disorder. The S252W mutation was significantly-associated with the presence of cleft palate (including bifid uvula) (P  = 0.05).Data about the cumulative impact of all of these factors for communicative participation using the therapy outcome measures were available for 47 patients: (30 S252W; 17 P253R). Patients with a S252W mutation had significantly more severe difficulties with communicative participation when compared to individuals with a P253R mutation (P  = 0.0005) Cochran-Armitage trend test.

CONCLUSIONS

Speech, language, communicative participation, and hearing difficulties are pervasive in patients with AS. The severity and functional impact of these difficulties are magnified in patients with the S252W mutation. Results reinforce the importance of considering patients with AS according to genotype.

Ontogenesis of the tear drainage system requires Prickle1-driven polarized basement membrane deposition

In terrestrial animals, the lacrimal drainage apparatus evolved to serve as conduits for tear flow; however, little is known about the ontogenesis of this system. Here, we define the anatomy of the fully formed tear duct in mice, characterize crucial morphogenetic events for the development of tear duct components and identify the site for primordial tear duct (PTD) initiation. We report that the PTD originates from the orbital lacrimal lamina, a junction formed by the epithelia of the maxillary and lateral nasal processes. We demonstrate that Prickle1, a key component of planar cell polarity signaling, is expressed in progenitors of the PTD and throughout tear duct morphogenesis. Disruption of Prickle1 stalls tear duct elongation; in particular, the loss of basement membrane deposition and aberrant cytoplasmic accumulation of laminin are salient. Altered cell adhesion, cytoskeletal transport systems, vesicular transport systems and cell axis orientation in Prickle1 mutants support the role of Prickle1 in planar cell polarity. Taken together, our results highlight a crucial role of Prickle1-mediated polarized basement membrane secretion and deposition in PTD elongation.

Malformation of Tear Ducts Underlies the Epiphora and Precocious Eyelid Opening in Prickle 1 Mutant Mice: Genetic Implications for Tear Duct Genesis

Purpose

Obstruction of the tear drainage causes a range of ocular surface disorders. Hitherto, the genetics of tear duct development and obstruction has been scarcely explored, and related animal models are lacking. This study aims to study the potential role of the Wnt/PCP pathway mediated by Prickle 1 in tear duct development and diseases.

Methods

A severe hypomorphic Prickle 1 mutant was generated. Histology and immunohistochemistry were performed to compare wild type, Prickle 1 hypomorphic, and null mutant tear ducts. In situ hybridization was conducted to identify the signaling components in the developing tear ducts. Three-dimensional (3D) reconstruction was used to detect the human embryonic tear duct.

Results

Here, we report that a severe Prickle 1 hypomorph mouse line exhibited epiphora. This phenotype was due to the blockage of the tear drainage by incompletely formed nasolacrimal duct (NLD) and lacrimal canaliculi (LC), which also causes precocious eyelid opening. We observed a dose-dependent requirement of Prickle 1 for tear duct outgrowth. An investigation of the expression of Wnt/PCP core genes demonstrated a subset of PCP signaling components expressed in the developing tear duct. Furthermore, Prickle 1 is not required for the expression of Fgfr2/Fgf10 and p63 genes, which are associated with the NLD and LC hypoplasia in humans. Last, we showed that Prickle 1 expression in the developing tear drainage system is conserved between mice and humans.

Conclusions

The study suggests that malformed tear ducts caused by disruption of Prickle 1 underlies the epiphora and precocious eyelid opening.

Apert Syndrome With FGFR2 758 C > G Mutation: A Chinese Case Report

Background: Apert syndrome is considered as one of the most common craniosynostosis syndromes with a prevalence of 1 in 65,000 individuals, and has a close relationship with point mutations in FGFR2 gene.

Case report: Here, we described a Apert syndrome case, who was referred to genetic consultation in our hospital with the symptom of craniosynostosis and syndactyly of the hands and feet. Craniosynostosis, midfacial retrusion, steep wide forehead, larger head circumference, marked depression of the nasal bridge, short and wide nose and proptosis could be found obviously, apart from these, ears were mildly low compared with normal children and there was no cleft lip and palate. Mutation was identified by sanger sequencing and a mutation in the exon 7 of FGFR2 gene was detected: p.Pro253Arg (P253R) 758 C > G, which was not found in his parents.

Conclusion: The baby had Apert syndrome caused by 758 C > G mutation in the exon 7 of FGFR2 gene, considering no this mutation in his parents, it was spontaneous.

Syndromic and Nonsyndromic Systemic Associations of Congenital Lacrimal Drainage Anomalies: A Major Review

PURPOSE

To review and summarize the syndromic, nonsyndromic, and systemic associations of congenital lacrimal drainage anomalies.

METHODS

The authors performed a PubMed search of all articles published in English on congenital lacrimal anomalies (1933-2016). Patients of these articles were reviewed along with the literature of direct references to syndromes and other systemic associations. Data reviewed included syndromic descriptions, systemic details, demographics, lacrimal presentations, management, and outcomes.

RESULTS

Syndromic and systemic associations with congenital lacrimal drainage disorders are not known to be common. Although familial presentations have been reported, the inheritance patterns are unclear for most anomalies. There is an increasingly growing evidence of a genetic basis to many lacrimal anomalies. However, few syndromes have either widespread or are frequently associated with lacrimal anomalies. Few sequences of distinct lacrimal presentations and intraoperative findings are seen. Surgical challenges in these patients are distinct and a thorough pre and intraoperative anatomical assessment, detailed imaging when indicated, and assessment and correction of associated periocular and facial abnormalities may facilitate good outcomes.

CONCLUSIONS

Lacrimal drainage anomalies associated with syndromic and nonsyndromic systemic conditions have certain unique features of their own and their surgical and anesthesia challenges are distinct. Diagnosis of congenital lacrimal drainage anomalies should prompt consideration of the possible presence of associated systemic abnormalities.

FGFR-associated craniosynostosis syndromes and gastrointestinal defects

Craniosynostosis is a relatively common birth defect characterized by the premature fusion of one or more cranial sutures. Examples of craniosynostosis syndromes include Crouzon (CS), Pfeiffer (PS), and Apert (AS) syndrome, with clinical characteristics such as midface hypoplasia, hypertelorism, and in some cases, limb defects. Mutations in Fibroblast Growth Factor Receptor-2 comprise the majority of known mutations in syndromic forms of craniosynostosis. A number of clinical reports of FGFR-associated craniosynostosis patients and mouse mutants have been linked to gastrointestinal tract (GIT) disorders, leading to the hypothesis of a direct link between FGFR-associated craniosynostosis syndromes and GIT malformations. We conducted an investigation to determine GIT symptoms in a sample of FGFR-associated craniosynostosis syndrome patients and a mouse model of CS containing a mutation (W290R) in Fgfr2. We found that, compared to the general population, the incidence of intestinal/bowel malrotation (IM) was present at a higher level in our sample population of patients with FGFR-associated craniosynostosis syndromes. We also showed that the mouse model of CS had an increased incidence of cecal displacement, suggestive of IM. These findings suggest a direct relationship between FGFR-related craniosynostosis syndromes and GIT malformations. Our study may shed further light on the potential widespread impact FGFR mutations on different developmental systems. Based on reports of GIT malformations in children with craniosynostosis syndromes and substantiation with our animal model, GIT malformations should be considered in any child with an FGFR2-associated craniosynostosis syndrome. © 2016 Wiley Periodicals, Inc.

Apert and Crouzon syndromes-Cognitive development, brain abnormalities, and molecular aspects

Apert and Crouzon are the most common craniosynostosis syndromes associated with mutations in the fibroblast growth factor receptor 2 (FGFR2) gene. We conducted a study to examine the molecular biology, brain abnormalities, and cognitive development of individuals with these syndromes. A retrospective longitudinal review of 14 patients with Apert and Crouzon syndromes seen at the outpatient Craniofacial Surgery Hospital for Rehabilitation of Craniofacial Anomalies in Brazil from January 1999 through August 2010 was performed. Patients between 11 and 36 years of age (mean 18.29 ± 5.80), received cognitive evaluations, cerebral magnetic resonance imaging, and molecular DNA analyses. Eight patients with Apert syndrome (AS) had full scale intelligence quotients (FSIQs) that ranged from 47 to 108 (mean 76.9 ± 20.2), and structural brain abnormalities were identified in five of eight patients. Six patients presented with a gain-of-function mutation (p.Ser252Trp) in FGFR2 and FSIQs in those patients ranged from 47 to78 (mean 67.2 ± 10.7). One patient with a gain-of-function mutation (p.Pro253Arg) had a FSIQ of 108 and another patient with an atypical splice mutation (940-2A →G) had a FSIQ of 104. Six patients with Crouzon syndrome had with mutations in exons IIIa and IIIc of FGFR2 and their FSIQs ranged from 82 to 102 (mean 93.5 ± 6.7). These reveal that molecular aspects are another factor that can be considered in studies of global and cognitive development of patients with Apert and Crouzon syndrome (CS). © 2016 Wiley Periodicals, Inc.

Strabismus in craniosynostosis

Strabismus is common in craniosynostosis, with rates from 39% to 90.9% in Crouzon, Apert, Pfeiffer, and Saethre-Chotzen syndromes. This article reviews the epidemiology of strabismus in these disorders and discusses competing theories of the mechanism, including absent muscles, excyclorotation of muscles, and instability of muscle pulleys. The authors then review options for surgical treatment of the often complex ocular misalignment in these disorders.

Pattern of craniofacial anomalies seen in a tertiary care hospital in Saudi Arabia

BACKGROUND AND OBJECTIVE

To date, there are no published studies from Saudi Arabia on the incidence or etiology of craniofacial anomalies. This study aimed to report the patterns of craniofacial anomalies in Saudi Arabia.

DESIGN AND SETTING

Hospital-based, descriptive study conducted during 2002 to 2009 in the Cleft Lip/Palate and Craniofacial Anomalies Registry at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.

PATIENTS AND METHODS

Data was collected on craniofacial patients in the registry.

RESULTS

Of the 447 craniofacial patients (male, 242; female, 205), 109 (24.4%) had only cranial anomalies, 261 (58.4%) had only facial anomalies and 77 (17.2%) had both of these conditions. Craniosynostosis was seen in 33.3% of the total patients (81 males and 68 females). Of the 65 craniosynostosis syndromic patients, 25 (38.5%) had Apert syndrome and 18 (27.7%) had Crouzon syndrome. Among facial anomalies, 47 (19.4%) had dysmorphic features, followed by 35 (14.5%) with micrognathia. Among facial syndromes, 72 (59.0%) were observed to have Pierre-Robin sequence, 17 (13.9%) had Goldenhar syndrome and another 17 (13.9%) had Van der Woude syndrome. Cleft palate was more common in 171 (56.8%) patients as an associated deformity, followed by cleft lip with cleft palate in 99 (32.9%) and cleft lip in 23 (7.6%) patients. Of the 224 patients having other congenital anomalies, the cardiovascular system was most commonly affected, with 46 (20.5%) children diagnosed with congenital heart disease. A family history of anomalies was observed more in children born to parents of a consanguineous marriage than in those whose parents were unrelated (P=.01).

CONCLUSIONS

Additional efforts should be made towards creating awareness among the general population about these deformities in relation to consanguinity.

The eye as an organizer of craniofacial development

The formation and invagination of the optic stalk coincides with the migration of cranial neural crest (CNC) cells, and a growing body of data reveals that the optic stalk and CNC cells communicate to lay the foundations for periocular and craniofacial development. Following migration, the interaction between the developing eye and surrounding periocular mesenchyme (POM) continues, leading to induction of transcriptional regulatory cascades that regulate craniofacial morphogenesis. Studies in chick, mice, and zebrafish have revealed a remarkable level of genetic and mechanistic conservation, affirming the power of each animal model to shed light on the broader morphogenic process. This review will focus on the role of the developing eye in orchestrating craniofacial morphogenesis, utilizing morphogenic gradients, paracrine signaling, and transcriptional regulatory cascades to establish an evolutionarily-conserved facial architecture. We propose that in addition to the forebrain, the eye functions during early craniofacial morphogenesis as a key organizer of facial development, independent of its role in vision.

Absence of all cyclovertical extraocular muscles in a child who has Apert syndrome

A 6-month-old patient with Apert syndrome underwent strabismus surgery for a hypertropic eye. At surgery, the patient was found to have agenesis of all four cyclovertical muscles in one eye. Further investigation by computed tomography demonstrated absence of all four cyclovertical muscles in the fellow eye as well. A transposition procedure corrected the strabismus. While isolated aberrant or missing extraocular muscles are well documented in patients with craniofacial syndromes, bilateral absence of all four cyclovertical muscles, as demonstrated in this patient, poses unique treatment challenges.