A Review of Anterior Segment Dysgeneses

Preoperative Structural Risk Factors for Glaucoma After Penetrating Keratoplasty for Congenital Corneal Opacity: An Observational Study

INTRODUCTION

Post-keratoplasty glaucoma (PKG) is a major complication following penetrating keratoplasty (PKP) for congenital corneal opacity (CCO). This study aims to assess the preoperative structural risk factors for PKG following PKP for CCO using ultrasound biomicroscopy (UBM).

METHODS

Pediatric patients with CCO who underwent preoperative UBM and primary PKP were enrolled. Patients with anterior segment operation history or with a follow-up duration less than 12 months were excluded. The structural features of the anterior segment including central corneal thickness, anterior chamber depth, angle closure range (ACR), anterior synechia range, maximum iridocorneal adhesion length, abnormal iridocorneal synechia, and lens anomalies were identified on UBM images. The medical histories were reviewed to identify clinical features. The incidence of PKG was assessed to determine significant structural and clinical risk factors.

RESULTS

Fifty-one eyes of 51 pediatric patients with CCO were included. The median age at surgery was 8.0 months, and the mean follow-up duration was 33 ± 9 months. Eleven (21.6%) eyes developed PKG. The main structural risk factors were abnormal iridocorneal synechia (P = 0.015), lens anomaly (P = 0.001), and larger ACR (P = 0.045). However, a larger range of normal anterior synechia without involvement of the angle was not a significant risk factor. Preoperative glaucoma (P < 0.001) and higher intraocular pressure (P = 0.015) were clinical risk factors. A shallow anterior chamber was a unique risk factor for sclerocornea (P = 0.019).

CONCLUSIONS

Detailed preoperative examination of iridocorneal synechia, lens, and angle closure using UBM is critical for PKG risk assessment, surgical prognosis evaluation, and postoperative management in patients with CCO.

Diagnostic Challenges of Axenfeld-Rieger Syndrome and a Novel FOXC1 Gene Mutation in a Polish Family

(1) Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder, the symptoms of which include both ocular and systemic abnormalities. In the studied subjects, the cornea was significantly opacified with peripheral scarring neovascularization, which is not specific to this syndrome. A suspicion of incorrect diagnosis was raised despite an initial diagnosis of a bilateral Chandler syndrome. (2) In order to provide the proper diagnosis, a DNA sequencing genetic test was conducted with three sisters carrying the presence of a genome imbalance in the FOXC1 gene. The aim of this study is to report a case of a Polish family with a novel gene mutation and its relation with ARS. (3) Our findings implicate the novel deletion of the FOXC1 gene in the pathogenesis of ARS in the affected family. The phenotypic variability observed, including differences in corneal and systemic anomalies, underscores the importance of genetic testing and suggests the influence of non-genetic factors on ARS manifestation.

Efficacy of the efficacy between dexamethasone versus triamcinolone acetonide after cataract surgery: A systematic review and meta-analysis

PURPOSE

To evaluate the clinical effects between dexamethasone and triamcinolone acetonide (TA) after phacoemulsification and intraocular lens implantation among cataract patients.

METHODS

Pubmed, Embase, and the Cochrane Library were searched for studies published up to August 2020. The primary outcome was intraocular pressure. The secondary outcomes were the logarithm of the minimum angle of resolution (logMAR), anterior chamber cell, and anterior chamber flare. The pooled effect sizes were expressed as weighted mean differences (WMDs) or standardized mean differences (SMDs) of 95% confidence intervals (95% CIs). Cochrane Collaboration risk of bias tool and Newcastle-Ottawa scale criteria were used for the quality assessment of included studies.

RESULTS

Seven relevant studies met the inclusion criteria. For the primary outcome, there was no significant difference between TA injection and dexamethasone in comparing intraocular pressure (IOP) (SMD = 0.22, 95% confidence interval [CI] [-0.29, 0.73], P = .408; I² = 86.9%) in the first day after treatment and last day of assessment. For the secondary outcomes, the logMAR (WMD = 0.01, 95% CI [-0.06, 0.08]) and the anterior chamber flare (SMD = 0.08, 95% CI [-0.01, 0.18], P = .087; I² = 0%) showed no differences. However, the amount of anterior chamber cells (SMD = -0.21, 95% CI [-0.42, -0.01], P = .044; I² = 0%) in the TA injection on the first day postoperative was higher than for dexamethasone. After treatment, there was no difference between the 2 groups.

CONCLUSIONS

This study supports that there were no differences in IOP, logMAR, and anterior chamber flare between TA injection and dexamethasone among cataract patients. TA injection treatment on the first day showed higher amounts of anterior chamber cells than with dexamethasone.

Magnetic Resonance Imaging Findings and Genetic Testing Results in Children With Congenital Corneal Opacities

PURPOSE

This study investigates brain and globe abnormalities identified on magnetic resonance imaging (MRI) in children with congenital corneal opacities (CCO).

DESIGN

Retrospective cohort study.

METHODS

Clinical notes, radiology records, and genetic testing results were reviewed for patients diagnosed with corneal opacification within the first 6 months of life at a tertiary referral academic center between August 2008 and January 2018. Ocular findings, systemic anomalies, neuroimaging, and genetic testing results were summarized.

RESULTS

A total of 135 patients presenting at age 1 day to 12 years (mean age, 1 year) were identified. Children with bilateral CCO were more likely to have systemic disease (P = 0.018). Of the entire cohort, 43 (31.8%) patients received MRI, of whom 27 (62.8%) had abnormal brain findings and 30 (69.7%) had abnormal orbital findings. The most common abnormal brain findings were ventriculomegaly (n = 16, 59.2%) and corpus callosum abnormalities (n = 10, 37.0%) followed by brainstem/pons anomalies (n = 5, 18.5%), and cerebellar anomalies (n = 2, 7.4%). Abnormal brain MRI findings were associated with the presence of neurologic (P = .003) and craniofacial (P = .034) disease. A total of 44 (32.1%) patients underwent genetic testing, of whom 29 (65.9%) had pathogenic results.

CONCLUSIONS

More than 60% of the children with CCO who underwent MRI had abnormal brain and orbit findings that were correlated with significant neurologic disease. Furthermore, almost two-thirds of patients with CCO who underwent genetic testing had pathogenic results. These data demonstrate the value of systemic workup in children with CCO, and highlight the role of ophthalmologists in facilitating the diagnosis of systemic comorbidities associated with CCO.

Genetic Aspects of Glaucoma: An Updated Review

Glaucoma is a group of diverse diseases characterized by cupping of the optic nerve head due to the loss of retinal ganglion cells. It is the most common cause of irreversible blindness throughout the world; therefore, its timely diagnosis and early detection through an ophthalmological examination are very important. We, herein, present the information on the epidemiology, pathophysiology, clinical diagnosis, and treatment of glaucoma. We also emphasize the investigations of the last decades that have allowed identifying numerous genes and susceptibility genetic factors. We have also described in detail the genes whose mutations cause or contribute to the development of the disease.

Axenfeld-Reiger syndrome: A search for the missing links

BACKGROUND

Axenfeld-Rieger syndrome (ARS) is a rare cause of congenital glaucoma and may result in loss of vision. ARS is mostly autosomal dominant in nature characterized by developmental abnormalities in the angle of anterior chamber and iris of the eye, also associated with structural abnormalities in the body.

AIM

To study and observe the demographics and clinical findings in a very rare ocular disease known as ARS.

METHODS

Case records of symptomatic patients attending Ophthalmology outpatient department and diagnosed to have ocular hypertension or glaucoma in 3 years from March 2017 to March 2020 were evaluated to search for cases diagnosed with ARS. Records of all patients diagnosed with ARS were then analysed for demographic and clinical characterization as well as management and success of therapy.

RESULTS

Eight out of ten patients with positive clinical signs were symptomatic and had glaucoma. One of these patients had limbal stem cell deficiency and another had vernal keratoconjunctivitis.

CONCLUSION

Clinical characterization of ARS is important for making a definitive diagnosis and determining prognosis.

Clinical and diagnostic imaging profile of three anterior segment dysgenesis disorders presenting with infantile corneal opacities

PURPOSE

To describe three anterior segment dysgenesis disorders with infantile corneal opacities, namely, congenital hereditary endothelial dystrophy (CHED), primary congenital glaucoma (PCG), and Peters anomaly (PA) in terms of clinical characteristics, histopathology, genetic association, and diagnostic imaging profiles using imaging modalities such as ultrasound biomicroscopy (UBM) and microscope-integrated intraoperative optical coherence tomography (i-OCT).

MATERIALS AND METHODS

Seventy-four eyes with 22 eyes of CHED, 28 eyes of PA, and 24 eyes of PCG were clinically evaluated and underwent imaging using UBM and i-OCT. Corneal buttons of 16 operated patients underwent histopathological analysis, while genetic analysis was done in 23 patients using whole-exome sequencing.

RESULTS

Corneal diameters (CD) and UBM parameters like anterior chamber depth (ACD), iris thickness (IT), and ciliary body (CB) thickness revealed a statistically significant difference between the three categories. In PA, 9 eyes had a third rare phenotype with only a posterior corneal defect with no iris adhesions. Genetic mutations were seen in all tested patients with CHED, in 83.3% of patients with PCG, and in 80% of patients with the third type of PA. i-OCT helped in the characterization of corneal opacity, identification of posterior corneal defects, iridocorneal adhesions, and contour of Descemet's membrane.

CONCLUSION

Overlapping phenotypes of the above disorders cause a diagnostic dilemma and parameters like CDs, UBM ACD, IT, and CB thickness help differentiate between them. i-OCT can help in classifying the diseases in a high resolution, non-contact manner, and can better delineate corneal characteristics. The rare third type of PA phenotype may have a genetic association.

Secondary developmental glaucoma

The basic pathophysiology of all childhood glaucoma results from impaired outflow through the trabecular meshwork. Anterior Segment Dysgeneses (ASD) are a group of nonacquired anomalies associated with secondary developmental glaucoma, characterized by impaired development of the structures of the anterior segment. Many genes impact the development of the anterior segment. The cause of the development of the abnormalities is thought to be multifactorial. Molecular research has helped our understanding of the molecular basis of ASD and the developmental mechanisms underlying these conditions. Identifying the genetic changes underlying ASD has gradually led to the recognition that some of these conditions may be parts of a disease spectrum rather than isolated anomalies. The characterization of the underlying genetic abnormalities responsible for glaucoma is the first step toward developing diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. It is also crucial for genetic counseling and risk stratification of later pregnancies. It also aids prenatal testing by various methods allowing for effective genetic counseling. This review summarizes various ocular and systemic conditions that result in secondary developmental glaucoma and provide an overview of the phenotypes, the diagnosis and principles of management of the various disorders.

Neuroimaging Findings in Axenfeld-Rieger Syndrome: A Case Series

Axenfeld-Rieger syndrome is an autosomal dominant condition associated with multisystemic features including developmental anomalies of the anterior segment of the eye. Single nucleotide and copy number variants in the paired-like homeodomain transcription factor 2 (PITX2) and forkhead box C1 (FOXC1) genes are associated with Axenfeld-Rieger syndrome as well as other CNS malformations. We determined the association between Axenfeld-Rieger syndrome and specific brain MR imaging neuroradiologic anomalies in cases with or without a genetic diagnosis. This case series included 8 individuals with pathogenic variants in FOXC1; 2, in PITX2; and 2 without a genetic diagnosis. The most common observation was vertebrobasilar artery dolichoectasia, with 46% prevalence. Other prevalent abnormalities included WM hyperintensities, cerebellar hypoplasia, and ventriculomegaly. Vertebrobasilar artery dolichoectasia and absent/hypoplastic olfactory bulbs were reported in >50% of individuals with FOXC1 variants compared with 0% of PITX2 variants. Notwithstanding the small sample size, neuroimaging abnormalities were more prevalent in individuals with FOXC1 variants compared those with PITX2 variants.

Pediatric glaucoma in aniridia in a population of Egyptian children

PURPOSE

To report on the incidence, characteristics, and treatment of glaucoma in association with aniridia in a population of Egyptian children.

METHODS

A retrospective chart review was conducted of children (<18 years of age) presenting with aniridia between 2007 and 2022. Diagnosis of glaucoma was based on cup:disk ratio (>0.3) and IOP (>16 mm Hg). Success of glaucoma surgery was defined as IOP ≤16 mm Hg and stable or regressing cup:disk ratio.

RESULTS

A total of 93 eyes of 47 children were included. The mean patient age at presentation was 41.2 ± 44.7 months. The mean intraocular pressure (IOP), corneal diameter, cup:disk ratio, and axial length on presentation were 16.4 ± 10.3 mm Hg, 11.4 ± 1.3 mm, 0.4 ± 0.3, and 22.43 ± 2.6 mm Hg. Of eyes with IOP and cup:disk ratio data at presentation, 23 (30%) were diagnosed with glaucoma. Fourteen eyes underwent surgery after presentation; follow-up data were available for half the remaining eyes. At the final follow-up, glaucoma was present in 20 eyes (49%). Glaucoma surgery was performed in 17 eyes, with a complete or qualified success rate of 82.4% at final follow-up, with 15 eyes having at least 12 months' follow-up.

CONCLUSIONS

In this study cohort, children with aniridia presented at around 3 years of age, with glaucoma at presentation in almost one-third of the cases.

Investigating the Clinical Characteristics and PITX3Mutations of a Large Chinese Family with Anterior Segment Mesenchymal Dysgenesis and Congenital Posterior Polar Cataract

Objective

To investigate the clinical characteristics and pathogenic genetic mutations of a Chinese family with anterior segment mesenchymal dysgenesis and congenital posterior polar cataract.

Methods

Through family investigation, the family members were examined via slit lamp anterior segment imaging and screened for eye and other diseases by eye B-ultrasound. Genetic test was performed on the blood samples of the fourth family generation (23 people) via whole exome sequencing (trio-WES) and Sanger sequencing.

Results

Among the 36 members in four family generations, there were 11 living cases with different degrees of ocular abnormalities, such as cataracts, leukoplakia, and small cornea. All patients who received the genetic test had the heterozygous frameshift mutation c.640_656dup (p.G220Pfs∗95) on exon 4 of the PITX3 gene. This mutation was cosegregated with the clinical phenotypes in the family and thus might be one of the genetic factors that cause the corresponding ocular abnormalities in this family.

Conclusion

The congenital posterior polar cataract with or without anterior interstitial dysplasia (ASMD) of this family was inherited in an autosomal dominant manner, and the frameshift mutation (c.640_656dup) in the PITX3 gene was the cause of ocular abnormalities observed in this family. This study is of great significance for guiding prenatal diagnosis and disease treatment.

Ophthalmological Manifestations of Axenfeld-Rieger Syndrome: Current Perspectives

Axenfeld-Rieger syndrome (ARS) is a rare congenital disease that is primarily characterized by ocular anterior segment anomalies but is also associated with craniofacial, dental, cardiac, and neurologic abnormalities. Over half of cases are linked with autosomal dominant mutations in either FOXC1 or PITX2, which reflects the molecular role of these genes in regulating neural crest cell contributions to the eye, face, and heart. Within the eye, ARS is classically defined as the combination of posterior embryotoxon with iris bridging strands (Axenfeld anomaly) and iris hypoplasia causing corectopia and pseudopolycoria (Rieger anomaly). Glaucoma due to iridogoniodysgenesis is the main source of morbidity and is typically diagnosed during infancy or childhood in over half of affected individuals. Angle bypass surgery, such as glaucoma drainage devices and trabeculectomies, is often needed to obtain intraocular pressure control. A multi-disciplinary approach including glaucoma specialists and pediatric ophthalmologists produces optimal outcomes as vision is dependent on many factors including glaucoma, refractive error, amblyopia and strabismus. Further, since ophthalmologists often make the diagnosis, it is important to refer patients with ARS to other specialists including dentistry, cardiology, and neurology.

The clinical and genetic findings in a Chinese family with Axenfeld-Rieger syndrome

Objecive

To describe the clinical and genetic findings of an Axenfeld-Rieger syndrome (ARS) family with a new PITX2 splicing mutation.

Methods

A Chinese ARS family with five affected individuals was recruited. Exome sequencing was performed on the proband and the variant (C.253-9C > A) in PITX2 gene was detected as a pathogenic mutation. Sanger sequencing was performed for verification and cosegregation analysis. Real-time polymerase chain reaction (RT- PCR) and Western blotting were performed to verify the expression of the pathogenic gene.

Results

All the patients showed abnormalities in the anterior segment of both eyes including posterior embryotoxon, corectopia, iris dysplasia, and iridocorneal tissue adhesions. In addition, they all presented systemic features, including maxillary hypoplasia, underbite, hypodontia, conical teeth. Only III-7 showed obvious umbilical skin. In the PITX2 family, we identified a novel heterozygous splicing mutation (C.253-9C > A) which was confirmed by Sanger sequencing to be completely cosegregated with the ARS phenotype. Real-time quantitative PCR and Western results showed that PITX2 mRNA and protein expression were significantly lower in patients compared with unrelated normal controls.

Conclusion

In the ARS pedigree, we summarized the variable phenotype, described a novel PITX2 splicing mutation which expand the genetic spectrum of ARS. We further confirmed the possibility of development of ARS induced by this PITX2 gene deficiency.

Dental and Maxillofacial Manifestations of Axenfeld–Rieger Syndrome: Presentation of a Case in a 5-Year-Old Girl

In this case study, the dental and maxillofacial manifestations of a 5-year-old girl with Axenfeld–Rieger syndrome (ARS) are described. This syndrome is characterized by craniomaxillofacial, ocular, dental, and umbilical disorders. The patient presented ocular dyscoria and corectopia, iris abnormalities, midface hypoplasia with a thin upper lip, and a protruded lower lip. Hyperplastic maxillary labial frenulum, oligodontia, ghost teeth, bilateral Class III molar and canine relationship, and right posterior crossbite were also found. An everted umbilicus with redundant periumbilical skin was evident. Early diagnosis of ARS is essential to establishing preventive and corrective measures that provide a good quality of life for patients who suffer from this syndrome.

Comparison of Anterior Segment Abnormalities in Individuals With FOXC1 and PITX2 Variants

PURPOSE

Axenfeld-Rieger syndrome encompasses a group of developmental disorders affecting the anterior chamber structures of the eye, with associated systemic features in some cases. This study aims to compare the difference in anterior segment phenotypes such as those involving the cornea, iris, lens, and anterior chamber angle between cases with disease-causing sequence variations in FOXC1 and PITX2 .

METHODS

This cross-sectional study involved 61 individuals, from 32 families with pathogenic FOXC1 or PITX2 variants, who were registered with the Australian and New Zealand Registry of Advanced Glaucoma.

RESULTS

The median age of the cohort was 39 years at the time of last assessment (range 3-85 years; females, 54%). Thirty-two patients had pathogenic variants in the FOXC1 gene, and 29 patients had pathogenic variants in the PITX2 gene. Corneal abnormalities were more common in individuals with FOXC1 variants (18/36, 50%) than those with PITX2 variants (4/25, 16%; P = 0.007). Iris abnormalities such as hypoplasia ( P = 0.008) and pseudopolycoria ( P = 0.001) were more common in individuals with PITX2 variants than those with FOXC1 variants. Glaucoma was present in 72% of participants. Corneal decompensation was positively associated with corneal abnormalities ( P < 0.001), glaucoma surgery ( P = 0.025), and cataract surgery ( P = 0.002).

CONCLUSIONS

Corneal abnormalities were more common in individuals with FOXC1 than in those with PITX2 variants and were often associated with early onset glaucoma. These findings highlight that patients with FOXC1 variations require close follow-up and monitoring throughout infancy and into adulthood.

Anterior segment dysgenesis: Insights into the genetics and pathogenesis

Childhood glaucoma is a treatable cause of blindness, provided it is recognized, diagnosed, and treated in time. WHO has estimated that it is responsible for Blind Years second only to cataracts. The fundamental pathophysiology of all childhood glaucoma is impaired outflow through the trabecular meshwork. Anterior segment Dysgeneses (ASD) are a group of non-acquired ocular anomalies associated with glaucoma, characterized by developmental abnormalities of the tissues of the anterior segment. The cause is multifactorial, and many genes are involved in the development of the anterior segment. Over the last decade, molecular and developmental genetic research has transformed our understanding of the molecular basis of ASD and the developmental mechanisms underlying these conditions. Identifying the genetic changes underlying ASD has gradually led to the recognition that some of these conditions may be parts of a disease spectrum. The characterization of genes responsible for glaucoma is the critical first step toward developing diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. It is also crucial for genetic counseling and risk stratification of later pregnancies. It also aids pre-natal testing by various methods allowing for effective genetic counseling. This review will summarize the known genetic variants associated with phenotypes of ASD and the possible significance and utility of genetic testing in the clinic.

Variable Anterior Segment Dysgenesis and Cardiac Anomalies Caused by a Novel Truncating Variant of FOXC1

Anterior segment dysgenesis (ASD) encompasses a wide spectrum of developmental abnormalities of the anterior ocular segment, including congenital cataract, iris hypoplasia, aniridia, iridocorneal synechiae, as well as Peters, Axenfeld, and Rieger anomalies. Here, we report a large five-generation Caucasian family exhibiting atypical syndromic ASD segregating with a novel truncating variant of FOXC1. The family history is consistent with highly variable autosomal dominant symptoms including isolated glaucoma, iris hypoplasia, aniridia, cataract, hypothyroidism, and congenital heart anomalies. Whole-exome sequencing revealed a novel variant [c.313_314insA; p.(Tyr105*)] in FOXC1 that disrupts the α-helical region of the DNA-binding forkhead box domain. In vitro studies using a heterologous cell system revealed aberrant cytoplasmic localization of FOXC1 harboring the Tyr105* variant, likely precluding downstream transcription function. Meta-analysis of the literature highlighted the intrafamilial variability related to FOXC1 truncating alleles. This study highlights the clinical variability in ASD and signifies the importance of combining both clinical and molecular analysis approaches to establish a complete diagnosis.

Anterior segment alterations in congenital primary aphakia-a clinicopathologic report of five cases

Purpose:

To report the clinicopathological features of corneal buttons in patients with congenital primary aphakia.

Methods:

Five corneal specimens of five patients with congenital primary aphakia who underwent penetrating keratoplasty (PKP) were studied by light microscopy, and immunohistochemistry with anti-smooth muscle (SMA) antibody.

Results:

All patients were born from consanguineous parents. Of the five, two patients were identical twins. All eyes were microphthalmic. In four patients, congenital primary aphakia was bilateral and in one patient (Patient 3), it was unilateral. PKP failed in all eyes due to hypotony. Histologically, Bowman's layer was absent in all specimens. The corneal stroma was thin; however, the stromal collagen showed thick and irregularly arranged fibers with neovascularization in all eyes. Descemet's membrane and the corneal endothelium were absent in all specimens. In three specimens, atrophic iris tissue without dilator muscle was adherent to the posterior corneal surface. In addition, anteriorly displaced hypoplastic ciliary body and/or pigmented and non-pigmented ciliary epithelium were attached to the posterior corneal surface in three of the five specimens. SMA staining demonstrated disorganized ciliary muscle in one case. SMA-positive stromal keratocytes demonstrated their myofibroblast nature.

Conclusion:

The corneal findings in congenital primary aphakia are similar to that seen in other causes of congenital corneal opacification. The anteriorly displaced hypoplastic ciliary body that was partially excised during keratoplasty explains the ocular hypotony in these eyes.

Novel heterozygous variants in PXDN cause different anterior segment dysgenesis phenotypes in monozygotic twins

BACKGROUND

Since bi-allelic variants in the PXDN gene were first discovered in 2011 to be associated with anterior segment dysgenesis, a spectrum of ophthalmologic and systemic clinical manifestations has been described. This manuscript reports two distinct clinical phenotypes in monozygotic twin sisters, including the previously unreported ocular manifestation of bilateral primary aphakia, associated with novel compound heterozygous variants in the PXDN gene.

MATERIALS AND METHODS

We used genome sequencing to study a non-consanguineous family with monozygotic twin sister probands: one presenting with bilateral microphthalmia, primary aphakia, total corneal opacification, congenital glaucoma, and complex systemic comorbidities; the other with anterior persistent fetal vasculature in the right eye, and Peters anomaly type 2 with cataract and iris coloboma in the left eye but no systemic issues. These findings were compared to published reports of PXDN-related ocular diseases upon comprehensive review of prior literature.

RESULTS

In both affected sisters, genome sequencing identified two novel heterozygous variants in trans in the PXDN gene: c.1569_1570insT, predicting p.(Thr524TyrfsTer53), and c.3206 C > A, predicting p.(Ala1069Asp), respectively. No other potentially diagnostic variants were identified in any other genes.

CONCLUSIONS

This report on two novel compound heterozygous variants in the PXDN gene associated with previously unreported clinical manifestations further expands the genotypic and phenotypic spectrum associated with this gene. Our finding of distinctive clinical phenotypes associated with identical compound heterozygous PXDN variants in monozygotic twins emphasizes the significant clinical variability that can occur, suggesting a potential role for stochastic developmental and/or epigenetic factors in the ultimate pathophysiologic pathway.

Childhood and Early Onset Glaucoma Classification and Genetic Profile in a Large Australasian Disease Registry

PURPOSE

To report the relative frequencies of childhood and early onset glaucoma subtypes and their genetic findings in a large single cohort.

DESIGN

Retrospective clinical and molecular study.

PARTICIPANTS

All individuals with childhood glaucoma (diagnosed 0 to <18 years) and early onset glaucoma (diagnosed 18 to <40 years) referred to a national disease registry.

METHODS

We retrospectively reviewed the referrals of all individuals with glaucoma diagnosed at <40 years of age recruited to the Australian and New Zealand Registry of Advanced Glaucoma (ANZRAG). Subtypes of glaucoma were determined using the Childhood Glaucoma Research Network (CGRN) classification system. DNA extracted from blood or saliva samples underwent sequencing of genes associated with glaucoma.

MAIN OUTCOME MEASURES

The phenotype and genotype distribution of glaucoma diagnosed at <40 years of age.

RESULTS

A total of 290 individuals (533 eyes) with childhood glaucoma and 370 individuals (686 eyes) with early onset glaucoma were referred to the ANZRAG. Primary glaucoma was the most prevalent condition in both cohorts. In the childhood cohort, 57.6% of individuals (167/290, 303 eyes) had primary congenital glaucoma (PCG), and 19.3% (56/290, 109 eyes) had juvenile open-angle glaucoma. Juvenile open-angle glaucoma constituted 73.2% of the early onset glaucoma cohort (271/370, 513 eyes). Genetic testing in probands resulted in a diagnostic yield of 24.7% (125/506) and a reclassification of glaucoma subtype in 10.4% of probands (13/125). The highest molecular diagnostic rate was achieved in probands with glaucoma associated with nonacquired ocular anomalies (56.5%). Biallelic variants in CYP1B1 (n = 29, 23.2%) and heterozygous variants in MYOC (n = 24, 19.2%) and FOXC1 (n = 21, 16.8%) were most commonly reported among probands with a molecular diagnosis. Biallelic CYP1B1 variants were reported in twice as many female individuals as male individuals with PCG (66.7% vs. 33.3%, P = 0.02).

CONCLUSIONS

We report on the largest cohort of individuals with childhood and early onset glaucoma from Australasia using the CGRN classification. Primary glaucoma was most prevalent. Genetic diagnoses ascertained in 24.7% of probands supported clinical diagnoses and genetic counseling. International collaborative efforts are required to identify further genes because the majority of individuals still lack a clear molecular diagnosis.

Etiologies and clinical characteristics of young patients with angle-closure glaucoma: a 15-year single-center retrospective study

Purpose

To investigate the etiologies and the clinical characteristics of angle-closure glaucoma (ACG) patients younger than 40 years old in Chinese.

Methods

Inpatients with diagnosis of ACG and diagnosed age younger than or equal to 40 years old, who were admitted in Eye, Ear, Nose, and Throat Hospital Fudan University from 2002 to 2017, were included in this retrospective non-comparative case series. The underlying causes and clinical features for all the patients were analyzed by comprehensive review of medical charts.

Results

A total of 298 patients (463 eyes) met the criteria, including 153 females (51.3%) and 145 males (48.7%); the mean age was 25.6 ± 13.0 years. Primary angle-closure glaucoma (PACG), uveitis, and anterior segment dysgenesis (ASD) were the top three etiologies in our patients, which accounted for 32.6%, 20.3%, and 15.1% of the total patients respectively. PACG mainly occurs after 30 years of age and ASD is the top reason of ACG in patients younger than 20 years old. Other known etiologies include iridocorneal endothelial syndrome, neovascular glaucoma, nanophthalmos, retinitis pigmentosa, spherophakia, bestrophinopathy, persistent fetal vasculature, iridociliary cysts, congenital retinoschisis, Marfan’s syndrome, retinopathy of prematurity, familial exudative vitreoretinopathy, congenital retinal folds, Coat’s disease, and neurofibromatosis.

Conclusions

We described the uncommon presentation of ACG in Chinese young patients. Although unusual, most of the etiologies could be identified. Therefore, more careful and comprehensive examinations are needed for early detection and timely treatment for young ACG patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05172-6.

Retrospective analysis of paediatric glaucoma at a tertiary referral centre in Hong Kong

PURPOSE

To evaluate the epidemiological features, clinical interventions, and outcomes of paediatric glaucoma in Hong Kong.

STUDY DESIGN

Retrospective chart review.

METHODS

Clinical data from the medical records of all patients under 18 years of age diagnosed with glaucoma from January 2008 to December 2017 at a university-affiliated, tertiary referral centre were collected. The patients' demographics, etiological distribution, clinical interventions, and outcomes were analysed.

RESULTS

A total of 33 subjects (53 eyes) were identified, 30 (49 eyes) of whom were Chinese. Primary glaucoma accounted for 21.2% of subjects, while 78.8% were diagnosed with secondary glaucoma. The most common subtype was juvenile-onset open angle glaucoma, followed by Sturge-Weber Syndrome related glaucoma. The most commonly performed surgical interventions were tube-shunt surgery (Ahmed Glaucoma Valve) and transscleral cyclophotocoagulation. Most eyes had significant reduction in intraocular pressure after medical or surgical intervention, but deterioration of visual acuity remained common.

CONCLUSION

Most cases of childhood glaucoma in Hong Kong are secondary rather than primary, similar to other regions with low incidence of parental consanguinity. The large proportion of secondary glaucoma which generally has poorer prognosis, is reflected by the frequency of multiple surgery, and a high incidence of visual deterioration despite significant intraocular pressure reduction in most eyes.

Corticosteroids in ophthalmology: drug delivery innovations, pharmacology, clinical applications, and future perspectives

Corticosteroids remain the mainstay of the treatment for various ocular conditions affecting the ocular surface, anterior and posterior segments of the eye due to their anti-inflammatory, anti-oedematous, and anti-neovascularization properties. Prednisolone, prednisolone acetate, dexamethasone, triamcinolone acetonide, fluocinolone acetonide, and loteprednol etabonate are amongst the most widely used ophthalmic corticosteroids. Corticosteroids differ in their activity and potency in the eye due to their inherent pharmacological and pharmaceutical differences. Different routes and regimens are available for ocular administration of corticosteroids. Conventional topical application to the eye is the route of choice when targeting diseases affecting the ocular surface and anterior segment, while periocular, intravitreal, and suprachoroidal injections can be potentially effective for posterior segment diseases. Corticosteroid-induced intraocular pressure elevation and cataract formation remain the most significant local risks following topical as well as systemic corticosteroid administration. Invasive drug administration via intracameral, subconjunctival, and intravitreal injection can enhance ocular bioavailability and minimize dose and dosing frequency of administration, yet may exacerbate ocular side effects of corticosteroids. This review provides a critical appraisal of the ophthalmic uses of corticosteroid, routes of administration, drug delivery fundamentals and novel ocular implantable steroid delivery systems, factors influencing side effects, and future perspectives for ocular corticosteroid therapy.

Novel mutations in the PITX2 gene in Pakistani and Mexican families with Axenfeld-Rieger syndrome

PURPOSE

Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder that affects the anterior segment of the eye. The aim of this study was to examine the PITX2 gene to identify possible novel mutations in Pakistani and Mexican families affected by the ARS phenotype.

METHODS

Three unrelated probands with a diagnosis of ARS were recruited for this study. Genomic DNA was isolated from the peripheral blood of the probands and their family members. Polymerase chain reaction and Sanger sequencing were used for the analysis of coding exons and the flanking intronic regions of the PITX2 gene. Bioinformatics tools and database (VarSome, Provean, and MutationTaster, SIFT, PolyPhen-2, and HOPE) were evaluated to explore missense variants.

RESULTS

We identified novel heterozygous variations in the PITX2 gene that segregated with the ARS phenotype within the families. The variant NM_153426.2(PITX2):c.226G > T or p.(Ala76Ser) and the mutation NM_153426.2(PITX2):c.455G > A or p.(Cys152Tyr) were identified in two Pakistani pedigrees, and the mutation NM_153426.2(PITX2):c.242_265del or p.(Lys81_Gln88del), segregated in a Mexican family.

CONCLUSION

Our study extends the spectrum of PITX2 mutations in individuals with ARS, enabling an improved diagnosis of this rare but serious syndrome.

Phenotype expansion of heterozygous FOXC1 pathogenic variants toward involvement of congenital anomalies of the kidneys and urinary tract (CAKUT)

PURPOSE

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of chronic kidney disease in childhood and adolescence. We aim to identify novel monogenic causes of CAKUT.

METHODS

Exome sequencing was performed in 550 CAKUT-affected families.

RESULTS

We discovered seven FOXC1 heterozygous likely pathogenic variants within eight CAKUT families. These variants are either never reported, or present in <5 alleles in the gnomAD database with ~141,456 controls. FOXC1 is a causal gene for Axenfeld-Rieger syndrome type 3 and anterior segment dysgenesis 3. Pathogenic variants in FOXC1 have not been detected in patients with CAKUT yet. Interestingly, mouse models for Foxc1 show severe CAKUT phenotypes with incomplete penetrance and variable expressivity. The FOXC1 variants are enriched in the CAKUT cohort compared with the control. Genotype-phenotype correlations showed that Axenfeld-Rieger syndrome or anterior segment dysgenesis can be caused by both truncating and missense pathogenic variants, and the missense variants are located at the forkhead domain. In contrast, for CAKUT, there is no truncating pathogenic variant, and all variants except one are located outside the forkhead domain.

CONCLUSION

We thereby expanded the phenotype of FOXC1 pathogenic variants toward involvement of CAKUT, which can potentially be explained by allelism.

The diagnosis and phacoemulsification in combination with intraocular lens implantation for an Axenfeld-Rieger syndrome patient with small cornea: a case report

BACKGROUND

Axenfeld-Rieger syndrome (ARS) is a congenital disease with a series of developmental abnormalities, and no case of ARS with cataract and small cornea has been reported in previous studies. In the present report, we aimed to describe the diagnosis and phacoemulsification of an ARS patient with small cornea.

CASE PRESENTATION

A 58-year-old Han Chinese male patient who was referred to Eye Center of the Second Affiliated Hospital of Zhejiang University Medical College was diagnosed with ARS. Systemic and ophthalmic examination and genetic testing were performed. The slit-lamp microscopic examination of anterior segment showed obvious nuclear cataract, iris lesions, and the abnormal cornea of both eyes with small transversal and longitudinal diameters. ARS with bilateral complicated cataract and small cornea was diagnosed. Microincision-phacoemulsification in combination with intraocular lens implantation was performed on his left eye. After successful surgery of his left eye, the best-corrected visual acuity (BCVA) was obviously improved from 2 to 0.5 (LogMAR). A transient elevation of intraocular pressure (IOP) was controlled with medication.

CONCLUSIONS

Through genetic testing, a known pathogenic mutation NM_153427.2:c.272G > A was detected on the PITX2 gene; and an unknown mutation NM_001453.2:c.1063C > T was detected on FOXC1 gene. For the ARS patient with complicated cataract, the visual acuity was increased by phacoemulsificasion in combination with microincision.

Ultrasound Biomicroscopy Detects Peters' Anomaly and Rieger's Anomaly in Infants

AIM

Congenital corneal opacities (CCOs) are the major causes of early visual deprivation in infants. Balloon ultrasound biomicroscopy (UBM) examination is an effective method to diagnose CCO. However, whether it is suitable for children examination is still unknown.

METHODS

26 Peters' anomaly (PA) or Rieger's anomaly (RA) infants with congenital corneal opacities (CCO) (40 eyes) underwent UBM examinations to study their imaging features.

RESULTS

Based on the results, they were divided into UBM Dx-Type I: Descemet's membrane (DM) and endothelium have heterogenous or discontinuous echo accompanied with corneal stroma echo-enhanced or shallow anterior chamber. Type II: Type I alteration plus abnormal strand of iris extended to the border of the posterior corneal defect or iridocorneal adhesion. Type III: Type I or II combined with the abnormal hyperechoic lens, lens luxation, or keratolenticular adhesion. Type IV: echoes of the DM and the endothelium are continuous, corneal stroma echo is enhanced, and an abnormal strand of peripheral iris extends to the prominent Schwalbe line, accompanied by iris stroma or pupil heteromorphism and a shallow or flat anterior chamber.

CONCLUSION

UBM not only could accurately evaluate the anterior segment abnormalities in CCO infants but also would be a step forward for the management of PA- and RA-associated CCO.

Anterior Chamber Angle Evaluation Using Gonioscopy: Consistency and Agreement between Optometrists and Ophthalmologists

SIGNIFICANCE

In our intermediate-tier glaucoma care clinic, we demonstrate fair to moderate agreement in gonioscopy examination between optometrists and ophthalmologists, but excellent agreement when considering open versus closed angles. We highlight the need for increased consistency in the evaluation and recording of angle status using gonioscopy.

PURPOSE

The consistency of gonioscopy results obtained by different clinicians is not known but is important in moving toward practice modalities such as telemedicine and collaborative care clinics. The purpose of this study was to evaluate the description and concordance of gonioscopy results among different practitioners.

METHODS

The medical records of 101 patients seen within a collaborative care glaucoma clinic who had undergone gonioscopic assessment by two clinicians (one optometrist and either one general ophthalmologist [n = 50] or one glaucoma specialist [n = 51]) were reviewed. The gonioscopy records were evaluated for their descriptions of deepest structure seen, trabecular pigmentation, iris configuration, and other features. These were compared between clinicians (optometrist vs. ophthalmologist) and against the final diagnosis.

RESULTS

Overall, 51.9 and 59.8% of angles were graded identically in terms of deepest visible structure when comparing between optometrist versus general ophthalmologist and optometrist versus glaucoma specialist, respectively. The concordance increased when considering ±1 of the grade (67.4 and 78.5%, respectively), and agreement with the final diagnosis was high (>90%). Variations in angle grading other than naming structures were observed (2.0, 30, and 3.9% for optometrist, general ophthalmologist, and glaucoma specialist, respectively). Most of the time, trabecular pigmentation or iris configuration was not described.

CONCLUSIONS

Fair to moderate concordance in gonioscopy was achieved between optometrists and ophthalmologists in a collaborative care clinic in which there is consistent feedback and clinical review. To move toward unified medical records and a telemedicine model, improved consistency of record keeping and angle description is required.

Loss of Crb2b-lf leads to anterior segment defects in old zebrafish

Defects in the retina or the anterior segment of the eye lead to compromised vision and affect millions of people. Understanding how these ocular structures develop and are maintained is therefore of paramount importance. The maintenance of proper vision depends, among other factors, on the function of genes controlling apico-basal polarity. In fact, mutations in polarity genes are linked to retinal degeneration in several species, including human. Here we describe a novel zebrafish crb2b allele (crb2be40 ), which specifically affects the crb2b long isoform. crb2be40 mutants are viable and display normal ocular development. However, old crb2be40 mutant fish develop multiple defects in structures of the anterior segment, which includes the cornea, the iris and the lens. Phenotypes are characterised by smaller pupils due to expansion of the iris and tissues of the iridocorneal angle, an increased number of corneal stromal keratocytes, an abnormal corneal endothelium and an expanded lens capsule. These findings illustrate a novel role for crb2b in the maintenance of the anterior segment and hence add an important function to this polarity regulator, which may be conserved in other vertebrates including humans.

Novel Ocular and Inner Ear Anomalies in a Patient with Myhre Syndrome

Myhre syndrome is a rare autosomal dominant multisystemic disorder. Typical features of this disorder include distinctive facial appearance, deafness, intellectual disability, cardiovascular abnormalities, short stature, brachydactyly, and skeletal anomalies. Gain-of-function mutations in the SMAD4 gene are responsible for this syndrome. Herein, we present a 9.6-year-old Turkish girl with molecularly confirmed Myhre syndrome who had novel findings including bilateral Axenfield Rieger anomaly with secondary glaucoma and bilateral enlarged vestibular aqueducts.

Axenfeld-Rieger Syndrome: Rare Case Presentation and Overview

Axenfeld-Rieger syndrome (ARS) is an extremely rare autosomal dominant disorder characterized by ocular, craniofacial, dental and periumbilical abnormalities. We present a case of a 10-year-old boy. Its awareness among oral surgeons is essential for timely diagnosis and subsequent prevention of ophthalmic and systemic complications as craniofacial and dental features constitute the early recognizable symptoms of this syndrome. Systematic ophthalmic surgeries aid in relieving vision abnormalities, while symptomatic dental treatment should be provided for masticatory and esthetic rehabilitation.

Novel PITX2 Mutations including a Mutation Causing an Unusual Ophthalmic Phenotype of Axenfeld-Rieger Syndrome

Purpose

The aims of this study were to examine novel mutations in PITX2 and FOXC1 in Chinese patients with anterior segment dysgenesis (ASD) and to compare the clinical presentations of these mutations with previously reported associated phenotypes.

Methods

Twenty-six unrelated patients with different forms of ASD were enrolled from our paediatric and genetic eye clinic. The ocular manifestations of both eyes of each patient were recorded. Genomic DNA was prepared from venous leukocytes. All coding exons of PITX2 and FOXC1 were amplified by polymerase chain reaction (PCR) from genomic DNA and subjected to direct DNA sequencing. Analysis of mutations in control subjects was performed by heteroduplex single-strand conformation polymorphism (SSCP) analysis.

Results

Sequence analysis of the PITX2 gene revealed four mutations, including c.475_476delCT (P.L159VfsX39), c.64C > T (P.Q22X), c.296delG (P.R99PfsX56), and c.206G > A (P.R69H). The first three mutations were found to be novel. The c.475_476delCT (P.L159VfsX39) mutation, located at the 3' end of the PITX2-coding region, was identified in a Chinese Axenfeld-Rieger syndrome (ARS) patient who presented with an unusual severe phenotype of bilateral aniridia. The clinical characteristics, including the severity and manifestations of the patient's phenotype, were compared with reported PITX2-associated aniridia phenotypes of ARS in the literature.

Conclusions

These results expand the mutation spectrum of the PITX2 gene in patients with ARS. The PITX2 gene may be responsible for a significant portion of ARS with additional systemic defects in the Chinese population. This is the first reported case of a mutation at the 3' end of the PITX2-coding region extending the phenotypic consequences to bilateral aniridia. The traits of ARS could display tremendous variability in severity and manifestations due to the dominant-negative effect of PITX2. Our results further emphasize the importance of careful clinical and genetic analysis in determining mutation-disease associations and may lead to a better understanding of the role of PITX2 in ocular development.

A novel frameshift mutation in the PITX2 gene in a family with Axenfeld-Rieger syndrome using targeted exome sequencing

BACKGROUND

Axenfeld-Rieger syndrome (ARS) is an autosomal dominant genetic disorder that is characterized by specific abnormalities of the anterior segment of the eye. Heterozygous mutations in two developmental transcription factor genes PITX2 and FOXC1 have been identified within ARS patients, accounting for 40 to 70% of cases. Our purpose is to describe clinical and genetic findings in a Chinese family with ARS.

METHODS

An ARS family with three affected members was recruited. The patients underwent a series of complete ophthalmologic examinations, general physical examination and dental radiography. DNA samples of proband II-1 were used for targeted exome sequencing of the FOXC1 and PITX2 genes. Sanger sequencing was used to validate the variation in PITX2. Quantitative real-time PCR was carried out to detect the expression of PITX2 in patients and normal controls.

RESULTS

All affected members showed iris atrophy, corectopia, shallow anterior chamber, complete or partial angle closure, and advanced glaucoma. In addition, they revealed systemic anomalies, including microdontia, hypodontia, and redundant periumbilical skin. A novel heterozygous frameshift variation, c.515delA, in PITX2 was found in the proband, which might lead to a truncated PITX2 protein (p.Gln172ArgfsX36). Sanger sequencing validated that the variation completely cosegregated with the ARS phenotype among this family, but was absent in 100 unrelated controls. Quantitative real-time PCR analysis revealed that the mRNA expression of PITX2 was significantly decreased in patients compared with that in unrelated normal controls.

CONCLUSIONS

PITX2 c.515delA (p.Gln172ArgfsX36) was the genetic etiology of our pedigree. The mutation led to decreased PITX2 gene expression and a truncated mRNA transcript.

Molecular characterization of Axenfeld-Rieger spectrum and other anterior segment dysgeneses in a sample of Mexican patients

BACKGROUND

Anterior segment dysgenesis (ASD) and Axenfeld-Rieger spectrum (ARS) are mainly due to PITX2 and FOXC1 defects, but it is difficult in some patients to differentiate among PITX2-, FOXC1-, PAX6- and CYP1B1-related disorders. Here, we set out to characterize the pathogenic variants (PV) in PITX2, FOXC1, CYP1B1 and PAX6 in nine unrelated Mexican ARS/ASD patients and in their available affected/unaffected relatives.

MATERIALS AND METHODS

Automated Sanger sequencing of PITX2, FOXC1, PAX6 and CYP1B1 was performed; those patients without a PV were subsequently analyzed by Multiplex Ligation-dependent Probe Amplification (MLPA) for PITX2, FOXC1 and PAX6. Missense variants were evaluated with the MutPred, Provean, PMUT, SIFT, PolyPhen-2, CUPSAT and HOPE programs.

RESULTS

We identified three novel PV in PITX2 (NM_153427.2:c.217G>A, c.233T>C and c.279del) and two in FOXC1 [NM_001453.2:c.274C>T (novel) and c.454T>A] in five ARS patients. The previously reported FOXC1 c.367C>T or p.(Gln123*) variant was identified in a patient with ASD. The ocular phenotype related to FOXC1 included aniridia, corneal opacity and early onset glaucoma, while an asymmetric ocular phenotype and aniridia were associated with PITX2. No gene rearrangements were documented by MLPA analysis, nor were any PV identified in PAX6 or CYP1B1.

CONCLUSIONS

Heterozygous PV in the PITX2 and FOXC1 genes accounted for 66% (6/9) of the ARS/ASD cases. The absence of PAX6 or CYP1B1 abnormalities could reflect our small sample size, although their analysis could be justified in ARS/ASD patients that present with congenital glaucoma or aniridia.

Bi-allelic Loss-of-Function Variants in DNMBP Cause Infantile Cataracts

Infantile and childhood-onset cataracts form a heterogeneous group of disorders; among the many genetic causes, numerous pathogenic variants in additional genes associated with autosomal-recessive infantile cataracts remain to be discovered. We identified three consanguineous families affected by bilateral infantile cataracts. Using exome sequencing, we found homozygous loss-of-function variants in DNMBP: nonsense variant c.811C>T (p.Arg271^∗) in large family F385 (nine affected individuals; LOD score = 5.18 at θ = 0), frameshift deletion c.2947_2948del (p.Asp983^∗) in family F372 (two affected individuals), and frameshift variant c.2852_2855del (p.Thr951Metfs^∗41) in family F3 (one affected individual). The phenotypes of all affected individuals include infantile-onset cataracts. RNAi-mediated knockdown of the Drosophila ortholog still life (sif), enriched in lens-secreting cells, affects the development of these cells as well as the localization of E-cadherin, alters the distribution of septate junctions in adjacent cone cells, and leads to a ∼50% reduction in electroretinography amplitudes in young flies. DNMBP regulates the shape of tight junctions, which correspond to the septate junctions in invertebrates, as well as the assembly pattern of E-cadherin in human epithelial cells. E-cadherin has an important role in lens vesicle separation and lens epithelial cell survival in humans. We therefore conclude that DNMBP loss-of-function variants cause infantile-onset cataracts in humans.

Microphthalmia With Multiple Anterior Segment Defects in Portuguese Water Dogs

Portuguese Water Dog breeders and veterinary ophthalmologists recognize microphthalmia with multiple congenital ocular anomalies. Fifteen Portuguese Water Dog puppies (<8 weeks of age; 8 females, 7 males) and 1 adult (5 years old; castrated male) with microphthalmia were examined. The 2 most common abnormalities were microphthalmia (31/32 eyes; 97%) and lens abnormality (congenital cataract or aphakia; 32/32 eyes; 100%). Other common histologic lesions included lack of both a ciliary cleft and trabecular meshwork (15/32 eyes; 47%) and abnormal relationship of anterior segment structures (15/32 eyes; 47%). Many of the observed lesions were similar to those described in various types of anterior segment dysgenesis in humans. Our findings define the histologic lesions in affected Portuguese Water Dogs and suggest a genetic defect that causes anterior segment malformation early in development.

Prognostic factors of pediatric glaucoma: a retrospective study

PURPOSE

To correlate the features of certain types of infantile glaucoma with the progression and the prognosis of the disease, highlighting probable risk factors.

METHODS

Seventy-six patients with pediatric glaucoma were recruited in this retrospective study. All patients underwent ophthalmological examination in the Department of Ophthalmology of the Saarland University Medical Center from January 2001 to December 2012. Our pediatric patients were classified into four different categories of glaucoma: (1) primary congenital glaucoma (presenting buphthalmus), (2) aniridia-related glaucoma, (3) Peters/Rieger's anomaly-related glaucoma and (4) congenital cataract-related glaucoma. Personal data comprised age, sex, nationality, systemic diseases and gestational age. The best-corrected visual acuity (BCVA), the cup-disk ratio (CDR), the intraocular pressure (IOP), the corneal diameter and thickness, along with the Haab striae and corneal haze, were recorded.

RESULTS

The majority of the children were male (58%) and suffered from aniridia-related glaucoma (38%). Children with aniridia exhibited the worst BCVA. The CDR and IOP were significantly higher in children with primary congenital glaucoma, compared to the other groups, at the first visit. Those children also were with the largest corneal diameter and prevalence of Haab striae compared to the rest groups, whereas corneal haze was found more often and was more pronounced in children with Peters/Rieger's syndrome.

CONCLUSIONS

We concluded that glaucoma was earlier detected in children with primary congenital glaucoma, who exhibited increased corneal diameter and high percentage of Haab striae comparing to the other groups. However, these children responded successfully to any therapeutic intervention, exhibiting better BCVA and IOP values than the rest groups at the second visit.

A novel mouse model of anterior segment dysgenesis (ASD): conditional deletion of Tsc1 disrupts ciliary body and iris development

Development of the cornea, lens, ciliary body and iris within the anterior segment of the eye involves coordinated interaction between cells originating from the ciliary margin of the optic cup, the overlying periocular mesenchyme and the lens epithelium. Anterior segment dysgenesis (ASD) encompasses a spectrum of developmental syndromes that affect these anterior segment tissues. ASD conditions arise as a result of dominantly inherited genetic mutations and result in both ocular-specific and systemic forms of dysgenesis that are best exemplified by aniridia and Axenfeld-Rieger syndrome, respectively. Extensive clinical overlap in disease presentation amongst ASD syndromes creates challenges for correct diagnosis and classification. The use of animal models has therefore proved to be a robust approach for unravelling this complex genotypic and phenotypic heterogeneity. However, despite these successes, it is clear that additional genes that underlie several ASD syndromes remain unidentified. Here, we report the characterisation of a novel mouse model of ASD. Conditional deletion of Tsc1 during eye development leads to a premature upregulation of mTORC1 activity within the ciliary margin, periocular mesenchyme and lens epithelium. This aberrant mTORC1 signalling within the ciliary margin in particular leads to a reduction in the number of cells that express Pax6, Bmp4 and Msx1 Sustained mTORC1 signalling also induces a decrease in ciliary margin progenitor cell proliferation and a consequent failure of ciliary body and iris development in postnatal animals. Our study therefore identifies Tsc1 as a novel candidate ASD gene. Furthermore, the Tsc1-ablated mouse model also provides a valuable resource for future studies concerning the molecular mechanisms underlying ASD and acts as a platform for evaluating therapeutic approaches for the treatment of visual disorders.

Mutations of conserved non-coding elements of PITX2 in patients with ocular dysgenesis and developmental glaucoma

Mutations in FOXC1 and PITX2 constitute the most common causes of ocular anterior segment dysgenesis (ASD), and confer a high risk for secondary glaucoma. The genetic causes underlying ASD in approximately half of patients remain unknown, despite many of them being screened by whole exome sequencing. Here, we performed whole genome sequencing on DNA from two affected individuals from a family with dominantly inherited ASD and glaucoma to identify a 748-kb deletion in a gene desert that contains conserved putative PITX2 regulatory elements. We used CRISPR/Cas9 to delete the orthologous region in zebrafish in order to test the pathogenicity of this structural variant. Deletion in zebrafish reduced pitx2 expression during development and resulted in shallow anterior chambers. We screened additional patients for copy number variation of the putative regulatory elements and found an overlapping deletion in a second family and in a potentially-ancestrally-related index patient with ASD and glaucoma. These data suggest that mutations affecting conserved non-coding elements of PITX2 may constitute an important class of mutations in patients with ASD for whom the molecular cause of their disease have not yet been identified. Improved functional annotation of the human genome and transition to sequencing of patient genomes instead of exomes will be required before the magnitude of this class of mutations is fully understood.

The rare Axenfeld-Rieger syndrome with systemic anomalies: A case report and brief review of literature

RATIONALE

Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder with ocular anterior segment dysgenesis and systemic anomalies.

PATIENT CONCERNS

A 28-year-old Chinese Han female was referred to Beijing Tongren Eye Center for progressive decrease of the visual acuity on her right eye in the past month.

DIAGNOSES

The patient was diagnosed as ARS with retinal detachment based on series of ophthalmic examinations performed.

INTERVENTIONS

A pars plana vitrectomy was performed to manage the retinal detachment.

OUTCOMES

Her best-corrected visual acuity was slightly improved after surgery.

LESSONS

ARS is a developmental defect of ocular anterior segment with various clinical manifestations which might cause misdiagnosis.

Type II Peter's anomaly with histopathological proof: a case report

BACKGROUND

Peter's anomaly is a rare congenital anterior segment dysgenesis with poor visual results. This case report describes a case of bilateral Type II Peter's anomaly with notable clinical and histopathological features.

CASE PRESENTATION

A 7-year-old boy was admitted to our center with complaints of bilateral central opacification, photophobia and severe reduced vision since birth. He underwent phacoemulsification, intraocular lens (IOL) implantation and anterior vitrectomy on the right eye in another medical institution two years ago. Slit lamp examination revealed bilateral central corneal opacity, few strands of peripheral iris, irregular pupils and cloudy lens with central adhesion to posterior corneal surface in the left eye. Additionally, a history of premature birth and mental retardation was also noted. The patient was diagnosed with Peter's anomaly in the left eye, pseudophakia in the right eye and bilateral amblyopia. Similar surgery to the right one was performed on the left eye. A vesicle-like structure was found in the anterior chamber intraoperatively, which was composed mainly of immature lens and some corneal stroma as revealed by postoperative histopathological examinations.

CONCLUSIONS

The exact mechanism of Peter's anomaly is not completely understood, however, the notable histopathological features of tissue obtained from the present case may provide evidence to the hypothesis of developmental anomalies.

Novel Genetic Findings in a Chinese Family with Axenfeld-Rieger Syndrome

Purpose

To describe a Chinese family with Axenfeld-Rieger syndrome (ARS) and report our novel genetic findings.

Methods

Nine members of the same family underwent complete ophthalmologic examinations and genetic analysis. Genomic DNA was isolated from veinal blood and amplifed using PCR; the products of PCR were sequenced and compared with FOXC1 and PITX2 genes, from which the mutations were found.

Results

Through the ophthalmologic examinations, 8 subjects were diagnosed as ARS and 1 subject was normal. A homozygous mutation c.1139_1141dupGCG(p.Gly380_Ala381insGly) and a heterozygous mutation c.1359_1361dupCGG(p.Gly456_Gln457insGly) in FOXC1 were identified in all subjects. The mutation (c.-10-30T>C) was identified in PITX2 in subjects III-1 and III-3.

Conclusions

We found novel gene mutations in a Chinese family with ARS, which provides us with a better understanding of the gene mutation spectrum of ARS and the assistance for the genetic counseling and gene-specific therapy in the future.

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.

Unusual Surprises in Glaucoma Filtering Surgeries: Lessons Learned and Review of Literature

PURPOSE

To describe an unusual series of complications after glaucoma filtering surgeries with their clinical findings and outcome after tailored non-conventional modes of therapy.

PATIENTS AND METHODS

Eighteen patients who underwent re-interventions (medical or surgical) after glaucoma filtering surgeries during the period at two tertiary centers, excluding those that required conventional modes of treatment (medical control or re-trabeculectomy, simple wound closure for traumatic wound dehiscence, bleb revision or needling, laser iridotomy), were included. Relevant clinical details with intraoperative videos, intraoperative or postoperative problems, and images with course after re-intervention were retrieved from the hospital database. Clinical details which helped in clinching diagnosis and cause for problems and course after intervention with final vision and intraocular pressure were evaluated.

RESULTS

Six of 18 eyes required surgical management for an unusual course of events after an uneventful filtering surgery. Bleb morphology and close follow-up of the conjunctiva, in addition to intraocular pressure (IOP) and anterior chamber (AC) configuration, helped diagnose possible aetiology and appropriate tailored management. All patients had good IOP and visual outcome in all except one with macular scar status after retinal detachment surgery.

CONCLUSION

Assessment of the bleb morphology in the postoperative course coupled with monitoring of the conjunctival wound are essential to conventional monitoring of IOP and anterior chamber configuration to arrive at appropriate management for rare unusual events after glaucoma surgery.