Conditions that can be mistaken as early childhood glaucoma

Exome Sequencing Reveals SLC4A11 Variant Underlying Congenital Hereditary Endothelial Dystrophy (CHED2) Misdiagnosed as Congenital Glaucoma

Autosomal recessive congenital hereditary endothelial dystrophy (CHED2) may be misdiagnosed as primary congenital glaucoma (PCG) due to similar clinical phenotypes during early infancy. In this study, we identified a family with CHED2, which was previously misdiagnosed as having PCG, and followed up for 9 years. Linkage analysis was first completed in eight PCG-affected families, followed by whole-exome sequencing (WES) in family PKGM3. The following in silico tools were used to predict the pathogenic effects of identified variants: I-Mutant 2.0, SIFT, Polyphen-2, PROVEAN, mutation taster and PhD-SNP. After detecting an SLC4A11 variant in one family, detailed ophthalmic examinations were performed again to confirm the diagnosis. Six out of eight families had CYP1B1 gene variants responsible for PCG. However, in family PKGM3, no variants in the known PCG genes were identified. WES identified a homozygous missense variant c.2024A>C, p.(Glu675Ala) in SLC4A11. Based on the WES findings, the affected individuals underwent detailed ophthalmic examinations and were re-diagnosed with CHED2 leading to secondary glaucoma. Our results expand the genetic spectrum of CHED2. This is the first report from Pakistan of a Glu675Ala variant with CHED2 leading to secondary glaucoma. The p.Glu675Ala variant is likely a founder mutation in the Pakistani population. Our findings suggest that genome-wide neonatal screening is worthwhile to avoid the misdiagnosis of phenotypically similar diseases such as CHED2 and PCG.

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.

Iris thickness and volume be measured using iris base instead of scleral spur as reference in anterior optical coherence tomography scan

PURPOSE:

To compare the iris parameters (iris thickness [IT] and volume) measured at different locations on iris determined using iris base (IB) and scleral spur (SS) in healthy Saudi eyes and factors affecting the differences.

METHODS:

Healthy eyes of Saudi persons were evaluated using anterior segment optical coherence tomography (AS-OCT). The IT was measured using Image J software and OCT scans in the horizontal axis in light on and light off condition. First IB was used as reference, and then, SS was used as reference for these measurements.

RESULTS:

One hundred healthy eye's AS-OCT scan was studied. The IT at the temporal side of the horizontal axis at 750 µ away from IB with lights on was 0.526 ± 0.08 µ, whereas it was 0.52 ± 0.08 µ from SS. The difference was significantly more in IB than SS method (P = 0.005). This difference if IT in SS and IB method was not affected by gender (Mann–Whitney P = 0.3), type of refractive error (K W P = 0.7), and level of illumination (K W P = 0.7).

CONCLUSION:

IT and IV measured using IB provided reliable data but overestimates compared to SS method. In the absence of SS visibility, IB could be alternative to assess iris parameters.

Megalocornea, anterior megalophthalmos, keratoglobus and associated anterior segment disorders: A review

Megalocornea and anterior megalophthalmos (megalocornea spectrum) disorders are typically defined by corneal diameter > 12.5 mm in the absence of elevated intraocular pressure. Clinical features overlap with keratoglobus but are distinct from buphthalmos and severe (globus) keratoconus. Megalocornea spectrum disorders and keratoglobus are primarily congenital disorders, often with syndromic associations; both can present with large and thin corneas, creating difficulty in diagnosis, however, only keratoglobus is typically progressive. Molecular genetics provide significant insight into underlying aetiologies. Nonetheless, careful clinical assessment remains intrinsic to diagnosis. Surgical management can be challenging due to the enlarged ciliary ring and weakened zonules in megalocornea spectrum disorders and the extreme corneal thinning of keratoglobus. In this review, the established literature on measurement of corneal diameter, diagnosis of megalocornea, anterior megalophthalmos and keratoglobus, differentiation from severe keratoconus, recent molecular genetics research and key surgical modalities in the management of these rare disorders are outlined and discussed.

Genetic testing results of children suspected to have Stickler syndrome type collagenopathy after ocular examination

Purpose

Stickler syndrome is a collagenopathy that is typically COL2A1‐related (autosomal dominant) and less commonly related to other collagen gene mutations. Diagnosis is straightforward when a child has myopia or retinal detachment in the setting of classic diagnostic criteria such as hearing impairment, midfacial hypoplasia, and arthropathy. However, some children have primarily ocular disease with mild or no extraocular features. Such children can remain undiagnosed unless suspicion is raised by the ophthalmologist.

Methods

Retrospective consecutive case series (2014–2016) of children (<12 years old) suspected to have Stickler syndrome type collagenopathy by a single ophthalmologist and able to complete genetic testing for this possibility. Suspicion was based on vitreous abnormalities and myopia or lens opacities in the setting of prior retinal detachment, hearing impairment, or facial flatness.

Results

Average age of the 12 identified children was 8 years old (range 3–11; five boys). Average spherical equivalent for phakic eyes was −13 (range −3.5 to −30). Nine children had lens opacities or aphakia; two with aphakia also had lens subluxation or iridodonesis. Other recurrent clinical features included flat facies (12/12), hearing impairment (5/12), and prior retinal detachment (4/12). Pathogenic variants for collagenopathy were uncovered in 10/12 children: COL11A1 (heterozygous) in six, COL2A1 (heterozygous) in two, and COL9A1 (homozygous) in two. One child was homozygous for pathogenic variation in LRPAP1. One child had no detectable gene mutations.

Conclusions

Taken together, these clinical features (particularly vitreous abnormality, myopia, and lens opacity) had a high molecular yield for collagen gene mutation. Ophthalmologists who see such children should suspect Stickler syndrome, even in the absence of overt systemic disease. COL11A1‐related rather than COL2A1‐related autosomal dominant disease may be more common when undiagnosed children are identified based on ocular examination. Biallelic mutations in LRPAP1 can result in a phenotype that may resemble Stickler syndrome.

Steroid-induced glaucoma: Epidemiology, pathophysiology, and clinical management

Glucocorticoids are a class of anti-inflammatory drugs commonly used to treat various ocular and systemic conditions. Although the role of glucocorticoids in the treatment of numerous serious inflammatory diseases is pivotal, their prolonged use may increase intraocular pressure resulting in steroid-induced glaucoma. We provide a detailed update on steroid-induced glaucoma as a preventable cause of blindness in the adult and pediatric population and describe its epidemiology, social impact, and risk factors. Furthermore, we explore the propensity of different steroids to increase the intraocular pressure, the role of different routes of steroid administration, dosage and duration of treatment, as well as the clinical features, genetics, and management of steroid-induced glaucoma.

Biallelic CPAMD8 Variants Are a Frequent Cause of Childhood and Juvenile Open-Angle Glaucoma

PURPOSE

Developmental abnormalities of the ocular anterior segment in some cases can lead to ocular hypertension and glaucoma. CPAMD8 is a gene of unknown function recently associated with ocular anterior segment dysgenesis, myopia, and ectopia lentis. We sought to assess the contribution of biallelic CPAMD8 variants to childhood and juvenile open-angle glaucoma.

DESIGN

Retrospective, multicenter case series.

PARTICIPANTS

A total of 268 probands and their relatives with a diagnosis of childhood or juvenile open-angle glaucoma.

PURPOSE

Developmental abnormalities of the ocular anterior segment in some cases can lead to ocular hypertension and glaucoma. CPAMD8 is a gene of unknown function recently associated with ocular anterior segment dysgenesis, myopia, and ectopia lentis. We sought to assess the contribution of biallelic CPAMD8 variants to childhood and juvenile open-angle glaucoma.

METHODS

Patients underwent a comprehensive ophthalmic assessment, with DNA from patients and their relatives subjected to genome, exome, or capillary sequencing. CPAMD8 RNA expression analysis was performed on tissues dissected from cadaveric human eyes.

MAIN OUTCOME MEASURES

Diagnostic yield within a cohort of childhood and juvenile open-angle glaucoma, prevalence and risk of ophthalmic phenotypes, and relative expression of CPAMD8 in the human eye.

RESULTS

We identified rare (allele frequency < 4×10^-5) biallelic CPAMD8 variants in 5.7% (5/88) of probands with childhood glaucoma and 2.1% (2/96) of probands with juvenile open-angle glaucoma. When including family members, we identified 11 individuals with biallelic variants in CPAMD8 from 7 unrelated families. Nine of these individuals were diagnosed with glaucoma (9/11, 81.8%), with a mean age at diagnosis of 9.22±14.89 years, and all individuals with glaucoma required 1 or more incisional procedures to control high intraocular pressure. Iris abnormalities were observed in 9 of 11 individuals, cataract was observed in 8 of 11 individuals (72.7%), and retinal detachment was observed in 3 of 11 individuals (27.3%). CPAMD8 expression was highest in neural crest-derived tissues of the adult anterior segment, suggesting that CPAMD8 variation may cause malformation or obstruction of key drainage structures.

CONCLUSIONS

Biallelic CPAMD8 variation was associated with a highly heterogeneous phenotype and in our cohorts was the second most common inherited cause of childhood glaucoma after CYP1B1 and juvenile open-angle glaucoma after MYOC. CPAMD8 sequencing should be considered in the investigation of both childhood and juvenile open-angle glaucoma, particularly when associated with iris abnormalities, cataract, or retinal detachment.

Congenital glaucoma and CYP1B1: an old story revisited

Primary congenital glaucoma is a trabecular meshwork dysgenesis with resultant increased intraocular pressure and ocular damage. CYP1B1 mutations remain the most common identifiable genetic cause. However, important questions about the penetrance of CYP1B1-related congenital glaucoma remain unanswered. Furthermore, mutations in other genes have been described although their exact contribution and potential genetic interaction, if any, with CYP1B1 mutations are not fully explored. In this study, we employed modern genomic approaches to re-examine CYP1B1-related congenital glaucoma. A cohort of 193 patients (136 families) diagnosed with congenital glaucoma. We identified biallelic CYP1B1 mutations in 80.8% (87.5 and 66.1% in familial and sporadic cases, respectively, p < 0.0086). The large family size of the study population allowed us to systematically examine penetrance of all identified alleles. With the exception of c.1103G>A (p.R368H), previously reported pathogenic mutations were highly penetrant (91.2%). We conclude from the very low penetrance and genetic epidemiological analyses that c.1103G>A (p.R368H) is unlikely to be a disease-causing recessive mutation in congenital glaucoma as previously reported. All cases that lacked biallelic CYP1B1 mutations underwent whole exome sequencing. No mutations in LTBP2, MYOC or TEK were encountered. On the other hand, mutations were identified in genes linked to other ophthalmic phenotypes, some inclusive of glaucoma, highlighting conditions that might phenotypically overlap with primary congenital glaucoma (SLC4A4, SLC4A11, CPAMD8, and KERA). We also encountered candidate causal variants in genes not previously linked to human diseases: BCO2, TULP2, and DGKQ. Our results both expand and refine the genetic spectrum of congenital glaucoma with important clinical implications.

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 Case Series of Dacryoendoscopy in Childhood: A Diagnostic and Therapeutic Alternative for Complex Congenital Nasolacrimal Duct Obstruction Even in the First Year of Life

INTRODUCTION

Congenital nasolacrimal duct obstruction (CNLDO) is the most common cause of epiphora in infancy. Spontaneous resolution occurs in the majority of the cases by 1 year of age. Nevertheless, obstruction has a negative impact on the outcome of conservative or surgical therapy, especially in cases of complex CNLDO. When the condition persists beyond several months, early intervention with dacryoendoscopy (DE) around the age of 1 year could yield good results. The objective of the study is to analyze the success rate and effectiveness of early DE for complex CNLDO in the first year of life.

METHODS

A retrospective, non-comparative case series is presented. DE was performed under general anesthesia in patients between the age of 1 and 12 months with severe recurrent acute or chronic dacryocystitis. The medical histories, intraoperative and postoperative results after 3 months as well as via parents' interviews were analyzed to investigate the success rate.

RESULTS

A total of 18 consecutive DE in 16 patients between the age of 1 and 12 months (mean 7.3 ± 3.4 months) were studied. Nine lacrimal ducts were diagnosed with persistent chronic dacryocystitis refractory to probing/syringing. The remaining 9 presented recurrent acute dacryocystitis. Diagnostic DE was performed in 18 cases. A therapeutic DE was conducted in 15 lacrimal ducts (83.3%) with simultaneous correction of the associated stenosiswith the tip of the endoscope. A visual controlled opening of the stenosis was impossible in 3 cases due to a too narrow presaccal anatomy (n = 1), an osseous duct stenosis (n = 1), and a bulging membrane of Hasner into the inferior nasal meatus (n = 1). Postoperative findings were classified into four categories: poor, fair, good and excellent. Good results were documented in 16.7% (n = 3) and excellent results in 77.7% (n = 14). The bony obstruction was treated with dacryocystorhinostomy. A minimum follow-up of 3 months was considered for final clinical analysis. Ten patients' parents (12 surgeries) were interviewed by telephone (mean follow-up 24.8 months). No recurrence of stenosis and no further postoperative complications were observed.

CONCLUSION

DE is a diagnostic and therapeutic option for complex CNLDO in patients before the age of 1 year. The outcome of DE in the 3 months follow-up is highly indicative of positive final results in terms of patency of the lacrimal duct.

Congenital hereditary endothelial dystrophy, not glaucoma, in a child with iris colobomas

Corneal haze and elevated measured intraocular pressure in a young child with iris abnormalities are suggestive for glaucoma, but primary corneal disease is another possibility. We highlight the case of a 10-year-old boy with these clinical signs who was initially treated for glaucoma but in fact had congenital hereditary endothelial dystrophy, iris colobomas, and no glaucoma.

A Surgical Approach to Pediatric Glaucoma

Glaucoma in children differs from adult-onset disease and typically requires surgical intervention. However, affected children exhibit a spectrum of disease severity and prospective data guiding the choice of operation are lacking. This article reviews common procedures and a surgical approach to pediatric glaucoma.

Corneal enlargement without optic disk cupping in children with recessive CYP1B1 mutations

Corneal enlargement during the first 3 years of life can be a sign of early childhood glaucoma and optic nerve head cupping is a useful confirmatory finding. We report 3 children with corneal enlargement without optic nerve head cupping who had recessive CYP1B1 mutations, the most common identifiable cause of primary congenital glaucoma. One child later developed unilateral Haab striae, still in the absence of optic disk cupping. These cases illustrate that CYP1B1-related corneal changes can occur in young children without visible optic nerve head damage.

CYP1B1 analysis of unilateral primary newborn glaucoma in Saudi children

Nonsyndromic primary newborn glaucoma, the most severe form of primary congenital glaucoma, typically is bilateral and often the result of CYP1B1 mutations, particularly in certain consanguineous populations. Truly unilateral cases are uncommon and genetically not well studied. During a 9-year period, we tested 5 consecutive children with unilateral primary newborn glaucoma from Saudi Arabia, where CYP1B1 mutations are the cause for 91% of bilateral primary newborn glaucoma cases. None of these children with unilateral primary newborn glaucoma harbored CYP1B1 mutations, suggesting that in this population the pathogenesis of unilateral disease differs from that of bilateral disease.