Incidence, ocular findings, and systemic associations of ocular coloboma: a population-based study

Ocular manifestations of renal ciliopathies

Renal ciliopathies are a common cause of kidney failure in children and adults, and this study reviewed their ocular associations. Genes affected in renal ciliopathies were identified from the Genomics England Panels. Ocular associations were identified from Medline and OMIM, and the genes additionally examined for expression in the human retina ( https://www.proteinatlas.org/humanproteome/tissue ) and for an ocular phenotype in mouse models ( http://www.informatics.jax.org/ ). Eighty-two of the 86 pediatric-onset renal ciliopathies (95%) have an ocular phenotype, including inherited retinal degeneration, oculomotor disorders, and coloboma. Diseases associated with pathogenic variants in ANK6, MAPKBP1, NEK8, and TCTN1 have no reported ocular manifestations, as well as low retinal expression and no ocular features in mouse models. Ocular abnormalities are not associated with the most common adult-onset "cystic" kidney diseases, namely, autosomal dominant (AD) polycystic kidney disease and the AD tubulointerstitial kidney diseases (ADTKD). However, other kidney syndromes with cysts have ocular features including papillorenal syndrome (optic disc dysplasia), Hereditary Angiopathy Nephropathy, Aneurysms and muscle Cramps (HANAC) (tortuous retinal vessels), tuberous sclerosis (retinal hamartomas), von Hippel-Lindau syndrome (retinal hemangiomas), and Alport syndrome (lenticonus, fleck retinopathy). Ocular abnormalities are associated with many pediatric-onset renal ciliopathies but are uncommon in adult-onset cystic kidney disease. However the demonstration of ocular manifestations may be helpful diagnostically and the features may require monitoring or treatment.

[Embryonic development and congenital diseases of the orbit]

Many neuroradiologists focus primarily on the central nervous system and give little attention to other regions like the eye/orbit. It is easy to be deceived by the pitfall called satisfaction of search (also abbreviated SOS), despite most congenital eye diseases being easily recognized if one is aware of them. In this article, the most common congenital orbital abnormalities are described, and their basic prenatal causes are summarized.

Ocular manifestations of congenital anomalies of the kidney and urinary tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common birth defects worldwide and a major cause of kidney failure in children. Extra-renal manifestations are also common. This study reviewed diseases associated with the Genomics England CAKUT-associated gene panel for ocular anomalies. In addition, each gene was examined for expression in the human retina and an ocular phenotype in mouse models using the Human Protein Atlas and Mouse Genome Informatics databases, respectively. Thirty-four (54%) of the 63 CAKUT-associated genes (55 'green' and 8 'amber') had a reported ocular phenotype. Five of the 6 most common CAKUT-associated genes (PAX2, EYA1, SALL1, GATA3, PBX1) that represent 30% of all diagnoses had ocular features. The ocular abnormalities found with most CAKUT-associated genes and with five of the six commonest were coloboma, microphthalmia, optic disc anomalies, refraction errors (astigmatism, myopia, and hypermetropia), and cataract. Seven of the CAKUT-associated genes studied (11%) had no reported ocular features but were expressed in the human retina or had an ocular phenotype in a mouse model, which suggested further possibly-unrecognised abnormalities. About one third of CAKUT-associated genes (18, 29%) had no ocular associations and were not expressed in the retina, and the corresponding mouse models had no ocular phenotype. Ocular abnormalities in individuals with CAKUT suggest a genetic basis for the disease and sometimes indicate the affected gene. Individuals with CAKUT often have ocular abnormalities and may require an ophthalmic review, monitoring, and treatment to preserve vision.

Isolated Chorioretinal Coloboma: A Case Report

Ocular coloboma is a rare congenital anomaly that arises due to an abnormality in embryogenesis. It occurs due to failed fusion of the embryonic fissure resulting in a persistent defect. Colobomas may present with vision loss but are most commonly asymptomatic and diagnosed incidentally. In this article, we present a case of asymptomatic chorioretinal coloboma diagnosed on routine screening. The patient was managed with prophylactic argon laser retinopexy to prevent complications leading to visual impairment in the future.

Clinical and Demographic Profile of Uveal Coloboma: A hospital-based Study of 14,371 eyes of 9557 Indian Patients

OBJECTIVE

To describe the demographics and clinical profile of uveal coloboma in patients presenting to a multi-tier ophthalmology hospital network in India.

DESIGN

Cross- sectional hospital -based study.

METHODS

This cross-sectional hospital-based study included 2,817,766 new patients presenting between August 2010 and May 2021. Patients with a clinical diagnosis of uveal coloboma in at least one eye were included as cases. The data were collected using an electronic medical record system.

RESULTS

Overall, 9,557 (0.34%) patients were diagnosed with uveal coloboma. Just over half of the patients were male (51.82%) and had bilateral (50.37%) affliction. The most common age group at presentation was during the second decade of life with 2,198 (23%) patients. The overall prevalence was higher in patients from a lower socio-economic status (0.53%) and presenting from the rural geography (0.39%). The most common type was retino-choroidal coloboma in 8,049 (84.22%) patients followed by iris coloboma in 2,129 (22.28%) patients. The most common Ida Mann classification in the eyes with retino-choroidal coloboma was type 4 in 7,049 (57.23%) eyes followed by type 2 in 3,685 (29.92%) eyes. In the 14,371 eyes, 5,696 (39.64%) eyes had a visual impairment of blindness (>20/400) followed by mild or no visual impairment (<20/70) in 2,875 (20.01%) eyes. In the 2,228 (15.5%) eyes that required a surgical/ laser intervention, cataract surgery was performed in 951 (6.62%) eyes, vitreo-retinal surgery in 661 (4.6%) eyes followed by laser photocoagulation in 357 (2.48%) eyes.

CONCLUSION

Uveal Coloboma is more common in males, is predominantly bilateral in the population studied. It is more commonly found in patients from lower socio-economic strata and from a rural background. The most common type is retino-choroidal coloboma and over a third of the eyes are affected with blindness.

OCT Imaging in Infants

Optical coherence tomography (OCT) is widely applied in diagnosis and management of retina diseases particularly macular diseases in adult retina practices. However, it has been under-utilized in pediatric retinal diseases especially in neonates and infants. Utilization of OCT in primary macular diseases in this age group is also uncommon and is less reported. Challenges involved in image acquisition and limitations with available devices technique can explain the limited research and accurate data availability in the literature in this field. Purpose of this review article is to summarize the use of OCT and its importance in various infantile retinal pathologies such as vascular diseases, tumors, retinal dystrophies, and optic nerve pathologies with primary focus on neonates and infants, along with infant choroid. In addition, we also discuss about future directions including OCT angiography for infants.

Ophthalmic manifestations of proboscis lateralis

Proboscis lateralis (PL) is a rare congenital malformation of the craniofacial structure with varied clinical associations. None of the studies documented a discrete review of ophthalmic presentations in PL. The principal aim of the present study is to explore the ophthalmic manifestations of PL. The ancillary goal is to derive a relationship between congenital deformity in PL and various ophthalmic anomalies. Databases were searched in order to obtain articles related to PL. A qualitative systematic analysis of 100 subjects was performed. In PL, eyelid coloboma (32.6%) is the most common ocular feature, followed by hypertelorism (25.3%), iris coloboma (22.4%), lacrimal system abnormality (20.7%), malpositioned eyebrow (14.4%) and retinochoroidal coloboma (12.9%). Sinonasal deformity is the most common systemic abnormality, detected in 87.9% of cases of PL, as compared with central nervous system involvement (56.2%) and other anomalies. The analysis showed a strong significant association between brain abnormalities and hypertelorism (p=0.000) and between brain abnormalities and micro-ophthalmia/anophthalmia (p=0.000). Statistically significant association was noted between cumulative ocular abnormalities and cumulative systemic abnormalities (p=0.001). The present study on PL reviewed the salient features of this rare congenital disorder. The study outcome provides a new aspect to concomitant ocular abnormalities. This study supports the view that other congenital anomalies in cases of PL had significant influence on certain ophthalmic anomalies.

Expanding the phenotypic spectrum consequent upon de novo WDR37 missense variants

Structural eye disorders are increasingly recognised as having a genetic basis, although current genetic testing is limited in its success. De novo missense variants in WDR37 are a recently described cause of a multisystemic syndromic disorder featuring ocular coloboma. This study characterises the phenotypic spectrum of this disorder and reports 2 de novo heterozygous variants (p.Thr115Ile, p.Ser119Tyr) in three unrelated Caucasian individuals. All had a clinical phenotype consisting of bilateral iris and retinal coloboma, developmental delay and additional, variable multisystem features. The variants fall within a highly conserved region upstream of the WD-repeat domains, within an apparent mutation cluster. Consistent with the literature, intellectual disability, structural eye disorders, epilepsy, congenital heart disease, genitorenal anomalies and dysmorphic facial features were observed. In addition, a broader developmental profile is reported with a more specific musculoskeletal phenotype described in association with the novel variant (p.Thr115Ile). We further expand the phenotypic spectrum of WDR37-related disorders to include those with milder developmental delay and strengthen the association of ocular coloboma and musculoskeletal features. We promote the inclusion of WDR37 on gene panels for intellectual disability, epilepsy and structural eye disorders.

Radiology of Abnormal Globe Contour

The orbits are easily identified on routine computed tomography (CT) and magnetic resonance imaging (MRI) imaging of the head and neck. Although there are many structures within the orbits, the overall structure of the globe is the most noticeable and can be an important source for pathology. In particular, many disease processes alter globe morphology and it is imperative that the radiologist be aware of not only the most common, but uncommon etiologies as well. This article provides an image-rich review of the wide range of emergent and non-emergent pathology that can result in altered globe contour.

Cataract surgery in eyes with associated coloboma: Predictors of outcome and safety of different surgical techniques

Purpose:

The aim of this study was to report the outcome of cataract surgery with different surgical techniques in eyes with coexisting coloboma and to define factors of prognostic importance.

Methods:

Retrospective case sheet review of patients presenting between January 2016 and December 2018, who underwent cataract surgery in eyes with coexisting coloboma.

Results:

Of the 3,30,231 cases operated during the study period, 280 eyes of 276 patients had associated colobomatous malformation. The prevalence of coloboma in eyes undergoing cataract surgery was 0.085%. The mean age of the patients was 46.4 years (range 19 - 88 years). Phacoemulsification (PE) was performed in 130 eyes (46.4%), manual small incision cataract surgery (M-SICS) was done in 115 eyes (41.1%), and 35 eyes (12.5%) underwent intra capsular cataract extraction. Intra-operative complications were noted in 26 (9%) eyes. Incidence of intra-operative and post-operative complications was comparable between PE and M-SICS groups (p = 0.94). The mean corrected distance visual acuity (CDVA) improved from logMAR 1.71 ± 0.62 to 0.87 ± 0.61 (p = 0.00009). On multivariate analysis, microcornea (p = 0.002), type 1 and 2 coloboma (p < 0.001), and intraoperative complications (p = 0.001) were associated with poor visual outcome.

Conclusion:

Favorable functional outcomes can be achieved with phacoemulsification in eyes with softer cataract and corneal diameter >8 mm and with M-SICS in eyes with hard cataracts and corneal diameter of 6–8 mm. PE should be considered as the primary choice whenever permissible by the corneal diameter and severity of nuclear sclerosis. Poor functional outcomes were seen in eyes with smaller corneal diameter, extensive chorioretinal coloboma, and intraoperative complications.

Ocular coloboma-a comprehensive review for the clinician

Typical ocular coloboma is caused by defective closure of the embryonal fissure. The occurrence of coloboma can be sporadic, hereditary (known or unknown gene defects) or associated with chromosomal abnormalities. Ocular colobomata are more often associated with systemic abnormalities when caused by chromosomal abnormalities. The ocular manifestations vary widely. At one extreme, the eye is hardly recognisable and non-functional—having been compressed by an orbital cyst, while at the other, one finds minimalistic involvement that hardly affects the structure and function of the eye. In the fundus, the variability involves the size of the coloboma (anteroposterior and transverse extent) and the involvement of the optic disc and fovea. The visual acuity is affected when coloboma involves disc and fovea, or is complicated by occurrence of retinal detachment, choroidal neovascular membrane, cataract, amblyopia due to uncorrected refractive errors, etc. While the basic birth anomaly cannot be corrected, most of the complications listed above are correctable to a great extent. Current day surgical management of coloboma-related retinal detachments has evolved to yield consistently good results. Cataract surgery in these eyes can pose a challenge due to a combination of microphthalmos and relatively hard lenses, resulting in increased risk of intra-operative complications. Prophylactic laser retinopexy to the border of choroidal coloboma appears to be an attractive option for reducing risk of coloboma-related retinal detachment. However, a majority of the eyes have the optic disc within the choroidal coloboma, thus making it difficult to safely administer a complete treatment.

Clinical diagnosis of presumed SOX2 gonadosomatic mosaicism

Purpose:

To describe a family with presumed SOX2 gonadosomatic mosaicism diagnosed upon ophthalmic examination of the proband’s mother.

Methods:

The family underwent comprehensive ophthalmic and physical examination. Variant detection was performed using trio exome analysis on peripheral leukocyte DNA from blood and saliva samples. Variant segregation analysis was performed using a custom panel NGS sequencing. An identified variant in the SOX2 gene was confirmed in the proband by Sanger sequencing.

Results:

We report an individual with bilateral microphthalmia, developmental delay, hearing loss, and dysmorphic features. Her mother was found to have asymptomatic forme fruste uveal coloboma affecting her anterior segment. Her father, aunt, and sisters were unaffected. Trio exome sequence analysis showed an apparent de novo heterozygous deletion in the proband, NM_003106.3:c.70_89del, NP_003097.1:p. (Asn24Argfs*65), classified as pathogenic. Testing of the other family members’ peripheral blood and saliva was negative for this variant. The iris transillumination abnormalities in the proband’s mother supports a gonadosomatic mosaicism scenario.

Conclusions:

The results from this family underscore the importance of performing detailed evaluations of the parents of apparently sporadically affected individuals with heritable ophthalmic disorders. The identification of mildly affected individuals could substantially alter recurrence risks.

Transscleral filtration revealing a chorioretinal coloboma

Purpose

We report the case of a 19-year-old patient who presented with an ocular hypotony due to a transscleral filtration through an isolated congenital chorioretinal coloboma in his right eye.

Observations

The initial examination showed a decimal best corrected visual acuity (BCVA) decreased to 0.7 and a marked hypotony. A localized infero-nasal chemosis and a conjunctival hyperemia were observed. The fundus examination showed chorioretinal folds and an edematous disc. In the infero-nasal retinal periphery, a chorioretinal coloboma was seen with a full-thickness scleral defect. Ultrasound biomicroscopy showed the area of the coloboma through which the percolation of fluid occurred.

Conclusions and importance

A favorable outcome was observed within 6 weeks and BCVA improved to 1.0 three months later. The intraocular pressure (IOP) increased to 11 mmHg, but the bleb-like filtration could still be seen together with some persistent chorioretinal folds. Ultrasound Biomicroscopy (UBM) imaging was helpful to understand the mechanism of this uncommon complication of a coloboma.

Clinical and histological features and outcomes of upper eyelid colobomas in the Saudi population

PURPOSE

To study the clinical features, histopathology, and management of congenital upper eyelid coloboma (CEC) in the Saudi population.

METHODS

A retrospective review of health records evaluated the demographics, histopathology, and surgical outcomes of patients with CEC.

RESULTS

Thirty-nine eyelids of 27 patients were included in this study. CEC was bilateral in 12 (44.4%) patients, isolated in 17 (62.9%), and as part of a syndrome in 10 (37.1%) patients. CEC was commonly located in the medial upper lid (22 lids, 56.4%) and mostly involved the full thickness of the lid (27 lids, 69.2%). Corneal adhesion (18 eyes, 46.1%) and poorly formed eyebrows (21 eyebrows, 53.8%) were the most common ocular/adnexa associations. Histopathology was similar in all cases and the main features were scarred dermis, atrophic orbicularis oculi, and atrophic or absent tarsus. Visual acuity at the final follow-up was 20/50 or better in 13 (33.3%) eyes. Complete lid closure without lagophthalmos after one or more surgical procedures was achieved in 11 (40.7%) cases.

CONCLUSIONS

CEC features in Saudi patients are similar to those described in the literature. Dermal scarring and defective orbicularis muscles are common. Achieving cosmetic and functional success after management remains challenging.

Spotlight on the pediatric eye: a pictorial review of orbital anatomy and congenital orbital pathologies

Orbital lesions in the pediatric population vary from adults in terms of their presentation, unique pathology, and imaging characteristics. The prompt and accurate diagnosis of these lesions is imperative to prevent serious consequences in terms of visual impairment and disfigurement. Along with dedicated ophthalmologic examination, imaging is instrumental in characterizing these lesions, both for accurate diagnosis and subsequent management. In our pictorial essay, we provide a basic review of orbital embryology, anatomy, and congenital orbital pathologies, with emphasis on radiological findings.

Clinical spectrum of non-syndromic microphthalmos, anophthalmos and coloboma in the paediatric population: a multicentric study from North India

AIMS

To describe the clinical features, visual acuity and causes of ocular morbidity in children (0-18 years) with microphthalmos, anophthalmos, and coloboma (MAC) from North India.

METHODS

A retrospective study conducted between October 2017 and September 2018 in three tertiary eye institutes, part of the Bodhya Eye Consortium with consensus led common pro formas. Children with complete clinical data and without syndromic/systemic involvement were included. The clinical phenotype was divided into isolated ocular coloboma (CB), coloboma with microcornea (CBMC), colobomatous microphthalmos (CBMO), non-colobomatous microphthalmos (MO) and anophthalmos (AO).

RESULTS

A total of 532 children with MAC were examined. Seventeen records were excluded due to incomplete data (0.2%). 515 children (845 eyes) were included: 54.4% males and 45.6% females. MAC was unilateral in 36% and bilateral in 64%. CB, CBMC, CBMO, MO and AO were seen in 26.4%, 31%, 22%, 8% and 12.5% of eyes, respectively. Nystagmus was found in 40%, strabismus in 23%, cataract in 18.7% and retinal detachment in 15%. Best-corrected visual acuity (BCVA) of <3/60 was seen in 62.4% eyes. Blindness (BCVA <3/60 in better eye) was seen in 42.8% of bilateral patients. Those with microcornea or microphthalmos with coloboma had worse BCVA (p<0.001). There were regional differences in the type of MAC phenotype presenting to the three institutes.

CONCLUSION

The MAC group of disorders cause significant ocular morbidity. The presence of microcornea or microphthalmos with coloboma predicts worse BCVA. The variation of the MAC phenotype with the district of origin of the patient raises questions of aetiology and is subject to further studies.

Incidence of congenital heart diseases in Chinese children with non-syndromic congenital blepharoptosis: a prospective observational study of 1053 patients

BACKGROUND

Congenital blepharoptosis (CBP) may be part of a large spectrum of birth defects presenting with other ocular or systemic conditions. Therefore, the aim of the study was to investigate the incidence of congenital heart diseases (CHD) in CBP children not associated with specific syndromes.

METHODS

A total of 1053 Chinese children diagnosed with non-syndromic CBP were consecutively enrolled and their cardiac structure was evaluated by echocardiography.

RESULTS

Forty children were identified with CHD. Twenty-four children had one type of structural malformation (simple CHD). Sixteen children had two or more types of structural malformation (complex CHD). CHD and complex CHD were more prevalent in patients with severe or bilateral ptosis. Multivariate analysis revealed that presence of severe ptosis and bilateral ptosis was independently associated with CHD occurrence.

CONCLUSIONS

We found an increased frequency of CHD in CBP children, suggesting a clinical need for routine echocardiography evaluation in CBP, especially in children with severe or bilateral ptosis.

Combined Transcranial-supraorbital and Transconjunctival Approach for Optic Nerve Coloboma with Ophthalmic Dysplasia Associated with Rheumatoid Arthritis

We report a 59-year-old woman with optic nerve coloboma and ophthalmic dysplasia associated with rheumatoid arthritis. She experienced progressive visual dysfunction over the course of several years and presented with headache and pain in the left eye. Since infancy the visual acuity of her left eye had been compromised and her eyesight worsened gradually until she was blind in the left eye. Macroscopic observation showed a reddish lesion on the sclera thought to be due to rheumatoid arthritis (RA). Magnetic resonance imaging and computed tomography disclosed a well-defined cystic lesion at the left retro-bulbar optic nerve within the optic nerve sheath. We selected the combined transcranial-supraorbital and transconjunctival approach to remove the eyeball after detaching the optic nerve. This technique was successful and the placement of an ocular prosthetic was cosmetically acceptable.

Repair of Superior Chorioretinal Coloboma-Associated Retinal Detachments: Case Report and Literature Review

Purpose:

This case report discusses the management of a patient with a superior chorioretinal coloboma-associated retinal detachment (RD), including surgical management, along with a review of the literature.

Methods:

A case report is presented.

Results:

A 58-year-old man presented with a chronic RD of the right eye that was symptomatic for approximately 1 year prior to presentation. On examination, he was found to have a macula-off RD associated with superior chorioretinal coloboma. He underwent 23-gauge pars plana vitrectomy with membrane peel, endolaser, and perfluoropropane (14%) gas tamponade. Three months after his surgery, his best-corrected visual acuity in his right eye was 20/250 distance and 20/80 near, and his retina remained attached.

Conclusions:

This case report describes surgical management of a superior chorioretinal coloboma-associated RD.

Ocular manifestations in Gorlin-Goltz syndrome

Background

Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients.

Results

Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients.

Conclusions

The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients.

Unilateral acute hydrops in a child with bilateral microcornea and iridofundal coloboma

A 15-year-old female child with history of bilateral poor vision since childhood presented with sudden onset pain, photophobia, and diminution of vision OD for 10 days. Visual acuity was hand motion OD and 1/60 OS. Slit lamp examination revealed microcornea OU with multiple intrastromal fluid clefts OD and an irregular cornea and iridofundal coloboma OS. A clinical diagnosis of acute corneal hydrops OD was made, and the child was subjected to intraoperative optical coherence tomography guided intrastromal fluid drainage with air tamponade. The corneal edema resolved completely within 2 weeks resuming visual acuity to 3/60 allowing laser delimitation of fundal coloboma OD.

Optic Disc Coloboma in children - prevalence, clinical characteristics and associated morbidity

PURPOSE

The aim of the study was to report prevalence, ocular outcome, neurological characteristics, cognitive and behavioural problems in children with optic disc coloboma (ODC).

METHODS

This was a population-based, cross-sectional study of 31 children between 2 and 18 years of age diagnosed with ODC. The children were part of a larger cohort of 184 children with congenital optic disc malformations. Clinical ophthalmological examinations, neurological assessments, behavioural and developmental screening were performed.

RESULTS

The prevalence of ODC was 8.9/100 000 children. Of the 31 patients, 18 had unilateral ODC (p = 0.21). The best-corrected visual acuity (BCVA) in the ODC eye ranged from blindness to 1.3 (median 0.3). BCVA was 0.82 in eyes with an isolated ODC (range 0.4-1.3) and 0.15 (range 0-0.5) in eyes with concurrent macular involvement (p < 0.0001). Nystagmus was observed more often in patients with bilateral ODC (9/13 versus 3/17, p = 0.004). Two patients had retinal detachment. Behavioural/psychological screening was performed in 21 patients with severe deficits identified in six cases. Intellectual disability was present in seven patients. Neurological dysfunction was diagnosed in 8/22 cases. All of the above children had already systemic diagnoses before the ODC diagnosis was made.

CONCLUSIONS

ODC was the second most common optic disc malformation in this cohort after optic nerve hypoplasia. The children had a wide range of ocular comorbidity. An isolated ODC without macular involvement was not associated with profound vision loss. The ability of screening in the regular child care centres to diagnose extraocular comorbidities was very good and referral to a paediatrician appears redundant in cases of normal development.

Ubiquitin-mediated proteasome degradation regulates optic fissure fusion

Optic fissure fusion is a critical event during retinal development. Failure of fusion leads to coloboma, a potentially blinding congenital disorder. Pax2a is an essential regulator of optic fissure fusion and the target of numerous morphogenetic pathways. In our current study, we examined the negative regulator of pax2a expression, Nz2, and the mechanism modulating Nlz2 activity during optic fissure fusion. Upregulation of Nlz2 in zebrafish embryos resulted in downregulation of pax2a expression and fissure fusion failure. Conversely, upregulation of pax2a expression also led to fissure fusion failure suggesting Pax2 levels require modulation to ensure proper fusion. Interestingly, we discovered Nlz2 is a target of the E3 ubiquitin ligase Siah. We show that zebrafish siah1 expression is regulated by Hedgehog signaling and that Siah1 can directly target Nlz2 for proteasomal degradation, in turn regulating the levels of pax2a mRNA. Finally, we show that both activation and inhibition of Siah activity leads to failure of optic fissure fusion dependent on ubiquitin-mediated proteasomal degradation of Nlz2. In conclusion, we outline a novel, proteasome-mediated degradation regulatory pathway involved in optic fissure fusion.

Summary: Optic fissure fusion, a key retinal morphogenic event highly sensitive to developmental signaling, is directly regulated by ubiquitin-mediated proteasomal degradation uncovering a novel regulatory pathway potentially correlated to incidence of coloboma.

Macular Colobomata: Comparison of Clinical and Optical Coherence Tomography Features With Serologic Results

PURPOSE

To assess the correlation between the morphologic features and serology in eyes with macular colobomata (MC).

DESIGN

Retrospective comparative case series.

METHODS

Setting: Institutional.

STUDY POPULATION

Patients presenting with MC to the retina clinic over a period of 2 years (January 2016 to December 2017). Interventional/Observational Procedure: Color fundus and swept-source optical coherence tomography (SSOCT) features were reviewed and assessed in 3 groups based on the serum IgG results: positive for Toxoplasma, positive for cytomegalovirus (CMV), and serology negative.

MAIN OUTCOME MEASURE

Morphologic features on clinical and OCT-based examination.

RESULTS

A total of 49 eyes of 27 patients were recruited. The mean age was 24.8 ± 14.9 years (range 7-60 years). While the lesion size, the presence of satellite lesions, choroidal excavation, and choroidal lacunae (large choroidal vessels) on SSOCT differed significantly among the groups, pigmentation, retinal fibrosis, shape, retinal vessel pattern, and choroidal vessel visibility did not vary significantly. The lesions in CMV serology-positive cases were mostly solitary (n = 8/8), large (n = 5/8) and deeply excavated (n = 8/8). The lesions in Toxoplasma serology-positive cases were mostly flat to shallow (n = 18/26), medium-sized (n = 19/26), and either a solitary lesion (n = 17/26) or multiple satellite lesions (n = 9/26). The lesions in serology-negative cases were mostly small to medium (n = 13/15), solitary (n = 15/15), deeply excavated lesions (n = 11/15) with choroidal lacunae (n = 8/15).

CONCLUSIONS

The clinical and SSOCT features such as the lesion size, the presence of satellite lesions, choroidal excavation, and choroidal lacunae can provide a clue toward the etiology of macular colobomata.

Joubert Syndrome: Ophthalmological Findings in Correlation with Genotype and Hepatorenal Disease in 99 Patients Prospectively Evaluated at a Single Center

PURPOSE

Joubert syndrome (JS) is caused by mutations in >34 genes that encode proteins involved with primary (nonmotile) cilia and the cilium basal body. This study describes the varying ocular phenotypes in JS patients, with correlation to systemic findings and genotype.

DESIGN

Patients were systematically and prospectively examined at the National Institutes of Health (NIH) Clinical Center in the setting of a dedicated natural history clinical trial.

PARTICIPANTS

Ninety-nine patients with JS examined at a single center.

METHODS

All patients underwent genotyping for JS, followed by complete age-appropriate ophthalmic examinations at the NIH Clinical Center, including visual acuity (VA), fixation behavior, lid position, motility assessment, slit-lamp biomicroscopy, dilated fundus examination with an indirect ophthalmoscope, and retinoscopy. Color and fundus autofluorescence imaging, Optos wide-field photography (Dunfermline, Scotland, UK), and electroretinography (ERG) were performed when possible.

MAIN OUTCOME MEASURES

The VA (with longitudinal follow-up where possible), ptosis, extraocular muscle function, retinal and optic nerve status, and retinal function as measured by ERG.

RESULTS

Among patients with JS with quantifiable VA (68/99), values ranged from 0 logarithm of the minimum angle of resolution (logMAR) (Snellen 20/20) to 1.5 logMAR (Snellen 20/632). Strabismus (71/98), nystagmus (66/99), oculomotor apraxia (60/77), ptosis (30/98), coloboma (28/99), retinal degeneration (20/83), and optic nerve atrophy (8/86) were identified.

CONCLUSIONS

We recommend regular monitoring for ophthalmological manifestations of JS beginning soon after birth or diagnosis. We demonstrate delayed visual development and note that the amblyogenic time frame may last significantly longer in JS than is typical. In general, patients with coloboma were less likely to display retinal degeneration, and those with retinal degeneration did not have coloboma. Severe retinal degeneration that is early and aggressive is seen in disease caused by specific genes, such as CEP290- and AHI1-associated JS. Retinal degeneration in INPP5E-, MKS1-, and NPHP1-associated JS was generally milder. Finally, ptosis surgery can be helpful in a subset of patients with JS; decisions as to timing and benefit/risk ratio need to be made on an individual basis according to expert consultation.

Familial congenital cataract, coloboma, and nystagmus phenotype with variable expression caused by mutation in PAX6 in a South African family

Purpose

To report on a clinical and genetic investigation of a large, multigenerational South African family of mixed ancestry with autosomal dominant congenital cataracts, coloboma, and nystagmus.

Methods

Ophthalmic examination was performed in 27 individuals from the same admixed South African family. DNA was sampled from either peripheral blood or buccal swabs in all 27 individuals, and whole genome sequencing was performed in six individuals. Sanger sequencing was used to validate the probable mutation in the remaining family members.

Results

Twenty-seven family members with 19 affected individuals were included in the study. The predominant phenotype, with highly variable expression, was congenital cataract (14 individuals), posterior segment coloboma (17 individuals), and nystagmus (18 individuals). Other features present included high myopia, microcornea, and strabismus. An R208W mutation in PAX6 (dbSNP rs757259413; HGMD CM930572; NM_000280.3:c.622G>A; NP_000271.1:p.Arg208Trp) was identified as being the most probable pathogenic mutation. Cosegregation of the mutation with the phenotype was confirmed in all 27 family members.

Conclusions

PAX6 is a highly conserved gene crucial for normal oculogenesis, and although mutations within the gene may cause an array of ocular developmental abnormalities, most are associated with aniridia and aniridia-related ocular defects. The observation that PAX6 aniridia phenotypes are largely associated with nonsense mutations and milder non-aniridia phenotypes with missense mutations suggested that there may be specific genotype-phenotype correlations for the gene. The R208W mutation in PAX6 identified in this family challenges this theory as it has previously been reported in three unrelated families and is associated with aniridia and non-aniridia phenotypes across the four families. PAX6 with its wide phenotypic associations and highly variable expression should be considered a candidate gene in the diagnostic screen for any ocular developmental abnormality.

Low-vision aids improve the visual performance of children with bilateral chorioretinal coloboma

PURPOSE

To quantify the improvements in visual performance for both distance and near tasks attained by children with bilateral chorioretinal coloboma (CRC) with use of low-vision aids (LVAs).

METHODS

This was a hospital-based, cross-sectional, interventional case series of children with bilateral CRC. Demographic data were collected through a structured questionnaire and review of medical records. Distance and near best-corrected visual acuity, contrast sensitivity, and reading speed were evaluated with refractive correction alone and with the use of LVAs (Keplerian telescopes for distance; handheld magnifiers and a tinted lens [400 nm filter] for near). Effects are presented as medians of differences with 95% binomial-exact confidence intervals.

RESULTS

Six children were included (median age, 11.5 years; range, 7-17 years), of whom 5 were already using LVAs on a daily basis. The use of a Keplerian telescope achieved a significant median improvement in distance best-corrected visual acuity of 0.75 logMAR (95% CI, 0.20-1.20). Contrast sensitivity was also improved across all tested spatial frequencies. Use of near LVAs resulted in a significant median improvement in near reading acuity of 0.47 logRAD (95% CI, 0.28-0.90). Critical print size and reading speed at N10 were also improved.

CONCLUSIONS

LVAs enable meaningful improvements in the visual performance of children with bilateral CRC, allowing noteworthy increases in distance and near visual acuities as well as good reading speeds at small print sizes.

Mutation of IPO13 causes recessive ocular coloboma, microphthalmia, and cataract

Ocular coloboma is a developmental structural defect of the eye that often occurs as complex ocular anomalies. However, its genetic etiology remains largely unexplored. Here we report the identification of mutation (c.331C>T, p.R111C) in the IPO13 gene in a consanguineous family with ocular coloboma, microphthalmia, and cataract by a combination of whole-exome sequencing and homozygosity mapping. IPO13 encodes an importin-B family protein and has been proven to be associated with the pathogenesis of coloboma and microphthalmia. We found that Ipo13 was expressed in the cornea, sclera, lens, and retina in mice. Additionally, the mRNA expression level of Ipo13 decreased significantly in the patient compared with its expression in a healthy individual. Morpholino-oligonucleotide-induced knockdown of ipo13 in zebrafish caused dose-dependent microphthalmia and coloboma, which is highly similar to the ocular phenotypes in the patient. Moreover, both visual motor response and optokinetic response were impaired severely. Notably, these ocular phenotypes in ipo13-deficient zebrafish could be rescued remarkably by full-length ipo13 mRNA, suggesting that the phenotypes observed in zebrafish were due to insufficient ipo13 function. Altogether, our findings demonstrate, for the first time, a new role of IPO13 in eye morphogenesis and that loss of function of IPO13 could lead to ocular coloboma, microphthalmia, and cataract in humans and zebrafish.

In-depth genomic analysis of the family of a young man with severe visual impairment reveals a new gene involved in eye development. Ocular coloboma encompasses various hereditary disorders in which the eyes form improperly. Many of the underlying genetic factors remain unidentified. Researchers led by Zi-Bing Jin at Wenzhou Medical University in China sequenced the genes of 28-year-old man with a recessive form of ocular coloboma. By comparing these genetic data against equivalent genome sequences from his healthy parents, Jin’s team identified a gene called IPO13 as the culprit. IPO13 has not been linked to human disease before, but the researchers demonstrated that switching off IPO13 expression in zebrafish embryos gave rise to underdeveloped eyes with defects in the iris and cornea. These findings give clinicians another potential indicator for early diagnosis of ocular coloboma.

Relationship between neural crest cell specification and rare ocular diseases

Development of the eye is closely associated with neural crest cell migration and specification. Eye development is extremely complex, as it requires the working of a combination of local factors, receptors, inductors, and signaling interactions between tissues such as the optic cup and periocular mesenchyme (POM). The POM is comprised of neural crest-derived mesenchymal progenitor cells that give rise to numerous important ocular structures including those tissues that form the optic cup and anterior segment of the eye. A number of genes are involved in the migration and specification of the POM such as PITX2, PITX3, FOXC1, FOXE3, PAX6, LMX1B, GPR48, TFAP2A, and TFAP2B. In this review, we will discuss the relevance of these genes in the development of the POM and how mutations and defects result in rare ocular diseases.

De novo apparent loss-of-function mutations in PRR12 in three patients with intellectual disability and iris abnormalities

PRR12 encodes a proline-rich protein nuclear factor suspected to be involved in neural development. Its nuclear expression in fetal brains and in the vision system supports its role in brain and eye development more specifically. However, its function and potential role in human disease has not been determined. Recently, a de novo t(10;19) (q22.3;q13.33) translocation disrupting the PRR12 gene was detected in a girl with intellectual disability and neuropsychiatric alterations. Here we report on three unrelated patients with heterozygous de novo apparent loss-of-function mutations in PRR12 detected by clinical whole exome sequencing: c.1918G>T (p.Glu640*), c.4502_4505delTGCC (p.Leu1501Argfs*146) and c.903_909dup (p.Pro304Thrfs*46). All three patients had global developmental delay, intellectual disability, eye and vision abnormalities, dysmorphic features, and neuropsychiatric problems. Eye abnormalities were consistent among the three patients and consisted of stellate iris pattern and iris coloboma. Additional variable clinical features included hypotonia, skeletal abnormalities, sleeping problems, and behavioral issues such as autism and anxiety. In summary, we propose that haploinsufficiency of PRR12 is associated with this novel multisystem neurodevelopmental disorder.

Morphogenetic defects underlie Superior Coloboma, a newly identified closure disorder of the dorsal eye

The eye primordium arises as a lateral outgrowth of the forebrain, with a transient fissure on the inferior side of the optic cup providing an entry point for developing blood vessels. Incomplete closure of the inferior ocular fissure results in coloboma, a disease characterized by gaps in the inferior eye and recognized as a significant cause of pediatric blindness. Here, we identify eight patients with defects in tissues of the superior eye, a congenital disorder that we term superior coloboma. The embryonic origin of superior coloboma could not be explained by conventional models of eye development, leading us to reanalyze morphogenesis of the dorsal eye. Our studies revealed the presence of the superior ocular sulcus (SOS), a transient division of the dorsal eye conserved across fish, chick, and mouse. Exome sequencing of superior coloboma patients identified rare variants in a Bone Morphogenetic Protein (Bmp) receptor (BMPR1A) and T-box transcription factor (TBX2). Consistent with this, we find sulcus closure defects in zebrafish lacking Bmp signaling or Tbx2b. In addition, loss of dorsal ocular Bmp is rescued by concomitant suppression of the ventral-specific Hedgehog pathway, arguing that sulcus closure is dependent on dorsal-ventral eye patterning cues. The superior ocular sulcus acts as a conduit for blood vessels, with altered sulcus closure resulting in inappropriate connections between the hyaloid and superficial vascular systems. Together, our findings explain the existence of superior coloboma, a congenital ocular anomaly resulting from aberrant morphogenesis of a developmental structure.

Ocular coloboma is a disease characterized by gaps in the lower portion of the eye and can affect the iris, lens, or retina, and cause loss of vision. Coloboma arises from incomplete closure of a transient fissure on the underside of the developing eye. Therefore, our identification of patients with similar tissue defects, but restricted to the superior half of eye, was surprising. Here, we describe an ocular developmental structure, the superior ocular sulcus, as a potential origin for the congenital disorder superior coloboma. Formation and closure of the sulcus are directed by dorsal-ventral eye patterning, and altered patterning interferes with the role of the sulcus as a pathway for blood vessel growth onto the eye.

A recurrent de novo mutation in ACTG1 causes isolated ocular coloboma

Ocular coloboma (OC) is a defect in optic fissure closure and is a common cause of severe congenital visual impairment. Bilateral OC is primarily genetically determined and shows marked locus heterogeneity. Whole-exome sequencing (WES) was used to analyze 12 trios (child affected with OC and both unaffected parents). This identified de novo mutations in 10 different genes in eight probands. Three of these genes encoded proteins associated with actin cytoskeleton dynamics: ACTG1, TWF1, and LCP1. Proband-only WES identified a second unrelated individual with isolated OC carrying the same ACTG1 allele, encoding p.(Pro70Leu). Both individuals have normal neurodevelopment with no extra-ocular signs of Baraitser-Winter syndrome. We found this mutant protein to be incapable of incorporation into F-actin. The LCP1 and TWF1 variants each resulted in only minor disturbance of actin interactions, and no further plausibly causative variants were identified in these genes on resequencing 380 unrelated individuals with OC.

Association of Pediatric Choroidal Neovascular Membranes at the Temporal Edge of Optic Nerve and Retinochoroidal Coloboma

PURPOSE

To describe the characteristics of pediatric choroidal neovascular membranes (CNVs) associated with retinochoroidal and optic nerve coloboma using optical coherence tomography (OCT) and their response to treatment.

DESIGN

Retrospective case series.

METHODS

Retrospective review of children <16 years of age with CNV and retinochoroidal and optic nerve coloboma from 1995-2015 who underwent OCT imaging using either handheld (Bioptigen, Morrisville, NC) or tabletop OCT (Spectralis; Heidelberg, Carlsbad, CA).

RESULTS

Eight eyes of 8 patients (3 males, 5 females) with a mean age of 4.1 ± 3.9 years (range 6 months-10 years) at diagnosis were included. Mean follow-up was 21.4 ± 12.1 months (range 7-38 months). An optic nerve coloboma was present in 2 eyes and combined optic nerve and retinochoroidal coloboma in 6 eyes. In all eyes, CNVs were located at the temporal margin of the coloboma closest to the macula. Fluorescein angiogram characteristics included staining without leakage suggesting inactivity (n = 6) and leakage (n = 2). OCT characteristics included subretinal fluid (n = 5), intraretinal fluid and cysts (n = 1), and subretinal hyperreflective material (n = 7). Two eyes received intravitreal bevacizumab (range 3-6) injections, one of which also underwent focal peripapillary laser. Both eyes showed improvement in subretinal or intraretinal fluid on OCT. Vision at presentation among those quantified ranged from 20/200 to 20/40 and at final follow-up from 20/400 to 20/30. Genetic or systemic abnormalities were seen in 6 patients.

CONCLUSIONS

Association of pediatric CNV occurrence at the temporal margin of retinochoroidal and optic nerve colobomas closest to the fovea has not been established before and careful OCT and angiographic assessment of this region is warranted. The CNV lesions exhibit a varied degree of response to treatment.

Congenital optic nerve anomalies

OBJECTIVE

To update the current knowledge about congenital optic disc anomalies.

METHODS

A comprehensive literature search was performed in the major biomedical databases.

RESULTS

Patients with these anomalies usually have poor vision in infancy. Refractive errors are common, and serous retinal detachment may develop in some of these anomalies. It is critically important to clinically differentiate between these congenital optic disc anomalies, as central nervous system malformations are common in some, whereas others may be associated with systemic anomalies.

CONCLUSIONS

Congenital optic disc anomalies are a heterogeneous group of pathologies with characteristic fundus appearance and systemic associations. We should always try to make a correct diagnosis, in order to ask for specific tests, as well as to provide an adequate follow-up.

Prevalence of ophthalmological abnormalities in children and adolescents with CHD: systematic review and meta-analysis of observational studies

BACKGROUND

CHDs form a complex and heterogeneous group of clinical entities, with high morbidity and mortality. With the advancement of surgical and invasive techniques and clinical treatment, the survival of these patients has increased significantly, and there are reports of a high prevalence of ocular abnormalities in this group. The objective of this study was to estimate the prevalence of ocular findings in children and adolescents diagnosed with CHD.

METHODS

A systematic search was conducted in the following databases: MEDLINE (via PubMed), EMBASE, and Cochrane CENTRAL, in addition to a manual search on studies published on the patient, from inception until August, 2014. Observational studies assessing the prevalence of ocular abnormalities in children and adolescents with CHDs were included.

RESULTS

Of the 2413 articles identified, eight were included, comprising a total of 1061 patients. Among them, the lowest and highest prevalences observed were 6.3 and 65%, respectively. The weighted average prevalence of ocular abnormalities was 32.5% (CI95% 19.3-49.3). Strabismus, cataracts, and retinopathy were the most frequently observed alterations.

CONCLUSION

The prevalence of ocular abnormalities in children and adolescents with CHDs was 32.5%, demonstrating that ocular consequences are not uncommon in this population and may have relevant clinical impact. These results reinforce the need for ophthalmological evaluation of patients with CHDs.

Clinical and Echographic Features of Retinochoroidal and Optic Nerve Colobomas

PURPOSE

We reported the clinical and echographic features of colobomas, prevalence of retinal detachment, and associated visual acuity in these patients.

METHODS

The study is a nonrandomized consecutive case series of 140 colobomatous eyes in 98 patients (age range, 0-83 years). Coloboma depth, width, volume, and relative coloboma excavation (coloboma depth/axial length) were measured using standardized echographic images. The presence of structural and other ocular abnormalities was noted. The clinical and echographic findings present were correlated with visual acuity of the patient. In addition, these features were correlated with the presence or absence of retinal detachment.

RESULTS

Increased relative coloboma excavation was significantly associated with an increased risk of retinal detachment. A relative coloboma excavation (ratio of coloboma depth to axial length) greater than 0.15 was associated with an increased risk of retinal detachment (52%), compared to those with a relative coloboma excavation less than 0.15 (23%, P = 0.014). The presence of any structural abnormality and the presence of a retrobulbar cyst were associated with increased risk of retinal detachment and severe visual impairment (worse than 20/200). Increased coloboma depth, width, volume, and relative coloboma excavation were not associated with increased risk of severe visual impairment.

CONCLUSIONS

Clinical and echographic features of colobomas may be used in predicting the risk of retinal detachment. Measuring relative coloboma excavation upon presentation may alter follow-up and assist in the diagnosis of retinal detachment.

EFTUD2 deficiency in vertebrates: Identification of a novel human mutation and generation of a zebrafish model

BACKGROUND

Congenital microphthalmia and coloboma are severe developmental defects that are frequently associated with additional systemic anomalies and display a high level of genetic heterogeneity.

METHODS

To identify the pathogenic variant in a patient with microphthalmia, coloboma, retinal dystrophy, microcephaly, and other features, whole exome sequencing analysis of the patient and parental samples was undertaken. To further explore the identified variant/gene, expression and functional studies in zebrafish were performed.

RESULTS

Whole exome sequencing revealed a de novo variant, c.473_474delGA, p.(Arg158Lysfs*4), in EFTUD2 which encodes a component of the spliceosome complex. Dominant mutations in EFTUD2 cause Mandibulofacial Dysostosis, Guion-Almeida type, which does not involve microphthalmia, coloboma, or retinal dystrophy; analysis of genes known to cause these ocular phenotypes identified several variants of unknown significance but no causal alleles in the affected patient. Zebrafish eftud2 demonstrated high sequence conservation with the human gene and broad embryonic expression. TALEN-mediated disruption was employed to generate a c.378_385 del, p.(Ser127Aspfs*23) truncation mutation in eftud2. Homozygous mutants displayed a reduced head size, small eye, curved body, and early embryonic lethality. Apoptosis assays demonstrated a striking increase in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive cells in the developing brain, eye, spinal cord, and other tissues starting at 30 hours postfertilization.

CONCLUSION

This study reports a novel mutation in EFTUD2 in a Mandibulofacial Dysostosis, Guion-Almeida type patient with unusual ocular features and the generation of a first animal model of eftud2 deficiency. The severe embryonic phenotype observed in eftud2 mutants indicates an important conserved role during development of diverse tissues in vertebrates.

Mutations in MAB21L2 result in ocular Coloboma, microcornea and cataracts

Ocular coloboma results from abnormal embryonic development and is often associated with additional ocular and systemic features. Coloboma is a highly heterogeneous disorder with many cases remaining unexplained. Whole exome sequencing from two cousins affected with dominant coloboma with microcornea, cataracts, and skeletal dysplasia identified a novel heterozygous allele in MAB21L2, c.151 C>G, p.(Arg51Gly); the mutation was present in all five family members with the disease and appeared de novo in the first affected generation of the three-generational pedigree. MAB21L2 encodes a protein similar to C. elegans mab-21 cell fate-determining factor; the molecular function of MAB21L2 is largely unknown. To further evaluate the role of MAB21L2, zebrafish mutants carrying a p.(Gln48Serfs*5) frameshift truncation (mab21l2Q48Sfs*5) and a p.(Arg51_Phe52del) in-frame deletion (mab21l2R51_F52del) were developed with TALEN technology. Homozygous zebrafish embryos from both lines developed variable lens and coloboma phenotypes: mab21l2Q48Sfs*5 embryos demonstrated severe lens and retinal defects with complete lethality while mab21l2R51_F52del mutants displayed a milder lens phenotype and severe coloboma with a small number of fish surviving to adulthood. Protein studies showed decreased stability for the human p.(Arg51Gly) and zebrafish p.(Arg51_Phe52del) mutant proteins and predicted a complete loss-of-function for the zebrafish p.(Gln48Serfs*5) frameshift truncation. Additionally, in contrast to wild-type human MAB21L2 transcript, mutant p.(Arg51Gly) mRNA failed to efficiently rescue the ocular phenotype when injected into mab21l2Q48Sfs*5 embryos, suggesting this allele is functionally deficient. Histology, immunohistochemistry, and in situ hybridization experiments identified retinal invagination defects, an increase in cell death, abnormal proliferation patterns, and altered expression of several ocular markers in the mab21l2 mutants. These findings support the identification of MAB21L2 as a novel factor involved in human coloboma and highlight the power of genome editing manipulation in model organisms for analysis of the effects of whole exome variation in humans.

aldh7a1 regulates eye and limb development in zebrafish

Uveal coloboma is a potentially blinding congenital ocular malformation caused by failure of the optic fissure to close during development. Although mutations in numerous genes have been described, these account for a minority of cases, complicating molecular diagnosis and genetic counseling. Here we describe a key role of aldh7a1 as a gene necessary for normal eye development. We show that morpholino knockdown of aldh7a1 in zebrafish causes uveal coloboma and misregulation of nlz1, another known contributor to the coloboma phenotype, as well as skeletal abnormalities. Knockdown of aldh7a1 leads to reduced cell proliferation in the optic cup of zebrafish, delaying the approximation of the edges of the optic fissure. The aldh7a1 morphant phenotype is partially rescued by co-injection of nlz1 mRNA suggesting that nlz1 is functionally downstream of aldh7a1 in regulating cell proliferation in the optic cup. These results support a role of aldh7a1 in ocular development and skeletal abnormalities in zebrafish.

Systemic abnormalities in children with congenital optic disc excavations

PURPOSE

Together with optic disc hypoplasia, excavated optic disc anomalies represent the most frequent congenital abnormality involving the optic nerve head. The purpose of the present study was to retrospectively review the results of a screening for extraocular abnormalities in children presenting with congenital optic disc excavations.

MATERIALS AND METHODS

The medical records of 37 patients diagnosed with a unilateral or bilateral non glaucomatous optic disc excavation were retrospectively reviewed to analyze the result of the extra ocular evaluation and to report the associated ocular abnormalities.

RESULTS

An ocular abnormality was observed in conjunction with the excavated optic disc in 31% of the eyes. The systematic investigations revealed the presence of at least one extra-ocular disorder in 48% of the cases, and the optic disc excavation could be considered as syndromic in 30% of patients. The prevalence of extraocular malformations was significantly higher in infants presenting with associated ocular malformations or abnormal vision/development.

CONCLUSIONS

The present study suggests that a systematic approach to search for any associated systemic abnormalities could be envisioned in patients presenting with congenital excavated optic discs, and particularly those presenting with abnormal vision, associated ocular defects or abnormal development.

Systemic diagnostic testing in patients with apparently isolated uveal coloboma

PURPOSE

To investigate the frequency and types of systemic findings in patients with apparently isolated uveal coloboma.

DESIGN

Cross-sectional observational study.

METHODS

setting: Single-center ophthalmic genetics clinic. study population: Ninety-nine patients with uveal coloboma seen at the National Eye Institute. observational procedure: Results of audiology testing, echocardiogram, brain magnetic resonance imaging, renal ultrasound, and total spine radiographs. main outcome measure: Prevalence of abnormal findings on systemic testing.

RESULTS

Uveal coloboma affected only the anterior segment in 8 patients, only the posterior segment in 23 patients, and both anterior and posterior segments in 68 patients. Best-corrected visual acuity (BCVA) of eyes with coloboma was ≥20/40 in 45% of eyes; 23% of eyes had BCVA of ≤20/400. The majority of patients (74%) had good vision (>20/60) in at least 1 eye. Ten of the 19 patients (53%) who underwent echocardiography had abnormalities, with ventral septal defects being the most prevalent. Abnormal findings were observed in 5 of 72 patients (7%) who had a renal ultrasound and in 5 of 29 patients (17%) who underwent a brain MRI. Audiology testing revealed abnormalities in 13 of 75 patients (17%), and spine radiographs showed anomalies in 10 of 77 patients (13%). Most findings required no acute intervention.

CONCLUSIONS

Although some patients with coloboma had evidence of extraocular abnormalities, the majority of findings on routine clinical examination did not require acute intervention, but some warranted follow-up. Results from the systemic evaluation of patients with coloboma should be interpreted with caution and in view of their clinical context.

Two cases of CHARGE syndrome with multiple congenital anomalies

We report on two cases of bilateral chorioretinal colobomas with ocular anomalies in patients with CHARGE syndrome. In the first case, a female infant was born at 36 + 5 weeks gestation. At birth, the patient demonstrated a small left eye. Slit-lamp examination revealed colobomas of both irises. Fundus examination showed both chorioretinal colobomas. Brain magnetic resonance imaging (MRI) showed left microphthalmia. Systemic evaluation revealed multiple congenital anomalies: benign external hydrocephalus, esophageal atresia with imperforate anus, atrial septal defect (ASD), ventricular septal defect, patent ductus arteriosis (PDA), and right mild hydronephrosis. In the second case, a male infant was born at 39 + 5 weeks gestation and demonstrated a dysmorphic appearance with an irregular left pupil and ptosis. Fundus examination of both eyes showed large chorioretinal colobomas involving the optic disc and posterior pole. The patient had multi-organ anomalies: right facial palsy, a left short, wide ear with a small lobe, congenital heart defects, such as ASD and PDA, left renal atresia, seizure disorder, and micropenis. Both cases revealed multiple anomalies including nearly all major and minor criteria of CHARGE syndrome which could be life-threatening to neonates. Thus, all neonates with ocular colobomas should have fully and detailed systemic examinations checking all minor criteria and even occasional findings of CHARGE syndrome.