Choroidal neovascular membrane associated with optic nerve coloboma in a patient with CHARGE association

Chromatin remodeler Chd7 regulates photoreceptor development and outer segment length

Mutations in the chromatin remodeling factor CHD7 are the predominant cause of CHARGE syndrome, a congenital disorder that frequently includes ocular coloboma. Although CHD7 is known to be required for proper ocular morphogenesis, its role in retinal development has not been thoroughly investigated. Given that individuals with CHARGE syndrome can experience visual impairment even in the absence of coloboma, a better understanding of CHD7 function in the retina is needed. In this study, we characterized the expression pattern of Chd7 in the developing zebrafish and mouse retina and documented ocular and retinal phenotypes in Chd7 loss-of-function mutants. Zebrafish Chd7 was expressed throughout the retinal neuroepithelium when retinal progenitor cells were actively proliferating, and later in subsets of newly post-mitotic retinal cells. At stages of retinal development when most retinal cell types had terminally differentiated, Chd7 expression remained strong in the ganglion cell layer and in some cells in the inner nuclear layer. Intriguingly, strong expression of Chd7 was also observed in the outer nuclear layer where it was co-expressed with markers of post-mitotic cone and rod photoreceptors. Expression of mouse CHD7 displayed a similar pattern, including expression in the ganglion cells, subsets of inner nuclear layer cells, and in the distal outer nuclear layer as late as P15. Two different mutant chd7 zebrafish lines were characterized for ocular and retinal defects. These mutants displayed microphthalmia, reduced numbers of cone photoreceptors, and truncated rod and cone photoreceptor outer segments. Reduced cone photoreceptor number and abnormal outer segments were also observed in heterozygous Chd7 mutant mice. Taken together, our results in zebrafish and mouse reveal a conserved, previously undescribed role for Chd7 in retinal development and photoreceptor outer segment morphogenesis. Moreover, our work suggests an avenue of future investigation into the pathogenesis of visual system defects in CHARGE syndrome.

Eyes on CHARGE syndrome: Roles of CHD7 in ocular development

The development of the vertebrate visual system involves complex morphogenetic interactions of cells derived from multiple embryonic lineages. Disruptions in this process are associated with structural birth defects such as microphthalmia, anophthalmia, and coloboma (collectively referred to as MAC), and inherited retinal degenerative diseases such as retinitis pigmentosa and allied dystrophies. MAC and retinal degeneration are also observed in systemic congenital malformation syndromes. One important example is CHARGE syndrome, a genetic disorder characterized by coloboma, heart defects, choanal atresia, growth retardation, genital abnormalities, and ear abnormalities. Mutations in the gene encoding Chromodomain helicase DNA binding protein 7 (CHD7) cause the majority of CHARGE syndrome cases. However, the pathogenetic mechanisms that connect loss of CHD7 to the ocular complications observed in CHARGE syndrome have not been identified. In this review, we provide a general overview of ocular development and congenital disorders affecting the eye. This is followed by a comprehensive description of CHARGE syndrome, including discussion of the spectrum of ocular defects that have been described in this disorder. In addition, we discuss the current knowledge of CHD7 function and focus on its contributions to the development of ocular structures. Finally, we discuss outstanding gaps in our knowledge of the role of CHD7 in eye formation, and propose avenues of investigation to further our understanding of how CHD7 activity regulates ocular and retinal development.

A Case of Polypoidal Choroidal Vasculopathy Associated With Optic Disc Drusen

We report a case of optic disc drusen (ODD) associated with peripapillary polypoidal choroidal vasculopathy (PCV). A 62-year-old Malay lady presented with both eye ODD and the left eye associated with peripapillary subretinal hemorrhage. Ultrasound B-scan and red-free photography confirmed the optic nerve head drusen findings bilaterally. Optical coherence tomography (OCT) of the left eye showed sharply elevated peripapillary pigment epithelial detachment with subretinal fluid. The presence of peripapillary polyps with branching vascular network in indocyanine green angiography of the left eye further confirmed the diagnosis of PCV and excluded choroidal neovascularization (CNV) secondary to ODD. Subsequently, the patient was treated with a combination of verteporfin photodynamic therapy with three monthly intravitreal ranibizumab injections. Three months after the combined treatment, OCT showed completely resolved subretinal fluid. ODD can cause compression of the subretinal vessels at the optic disc that results in retinal ischemia and release of vascular endothelial growth factor, which may trigger the development of CNV or PCV. The rarity of this combination makes it interesting to study more cases of ODD with PCV. Importantly, a thorough evaluation in distinguishing the PCV from the CNV that mimics it is crucial for early detection and prompt intervention. In this case, indocyanine green angiography (ICGA) is the diagnostic method to differentiate the PCV from CNV secondary to ODD.

Polypoidal Choroidal Vasculopathy Associated with Optic Disc Coloboma

Purpose

To report a case of polypoidal choroidal vasculopathy associated with optic disc coloboma.

Methods

Case report.

Results

A 50-year-old woman presented with optic disc coloboma and retinochoroidal coloboma associated with subretinal hemorrhage and serous retinal detachment (SRD) in her left eye. Optical coherence tomography (OCT) confirmed SRD at the macula and showed a sharply elevated retinal epithelial detachment at the choroidal excavation. OCT also revealed choroidal cavitation along the temporal side of the optic coloboma. Fluorescein angiography showed hyperfluorescent dye leakage and indocyanine green angiography revealed polypoidal lesions. We diagnosed polypoidal choroidal vasculopathy (PCV). PCV was located at the end of the choroidal cavitation. Her left eye was treated with an intraocular injection of the anti-vascular endothelial growth factor aflibercept (2 mg). Photodynamic therapy was performed using the standard protocol 1 week after the intravitreal application of aflibercept. One month after the combined treatment, OCT showed completely resolved SRD and her symptoms disappeared. Her best-corrected visual acuity remained stable and no recurrence was found during a 12-month follow-up period.

Conclusion

PCV associated with optic disc coloboma has not been previously reported. The morphological abnormality of choroidal cavitation and choroidal excavation connecting with optic disc coloboma may contribute to the development of PCV in this case.

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.

Chorioretinal Coloboma Complications: Retinal Detachment and Choroidal Neovascular Membrane

Purpose:

To report the chorioretinal coloboma, and its association with increased risk of retinal detachment (RD) and choroidal neovascularization (CNV).

Methods:

This retrospective case series included eyes with chorioretinal coloboma diagnosed between 1995 and 2014 with a focus on RD and CNV as related complications. Cases of CNV were managed with laser photocoagulation or intravitreal injection of bevacizumab. For eyes with CNV, therapeutic success was defined as resolution of the subretinal hemorrhage on fundus examination and resolution of the subretinal and intraretinal fluid on optical coherence tomography (OCT). For eyes with RD, anatomic success following surgical intervention was defined as attachment of the retina at the last follow-up visit.

Results:

Fifty-one eyes of 31 patients with chorioretinal coloboma were identified for review. Bilateral chorioretinal coloboma was present in 64.5% of subjects. RD developed in 15 eyes (29.4%). Among 15 eyes with RD, 4 eyes (27%) had retinal breaks identified within the coloboma, 5 eyes (33%) had retinal breaks outside the coloboma, 2 eyes (13%) showed retinal breaks both inside and outside the coloboma, and in 4 eyes (27%) the causative retinal break was not localized. The overall rate of anatomic success after RD repair was 85.7%. CNV developed in 7 eyes (13.7%) and was located along the margin of the coloboma in all cases. CNV was bilateral in 2 of the 5 affected individuals (40%).

Conclusion:

RD and CNV were present in a high percentage of eyes with chorioretinal coloboma in these series. The frequent finding of retinal breaks outside the coloboma bed suggests that vitreoretinal interface abnormalities may play a role in development of RD in these eyes.

Neural crest derivatives in ocular development: discerning the eye of the storm

Neural crest cells (NCCs) are vertebrate-specific transient, multipotent, migratory stem cells that play a crucial role in many aspects of embryonic development. These cells emerge from the dorsal neural tube and subsequently migrate to different regions of the body, contributing to the formation of diverse cell lineages and structures, including much of the peripheral nervous system, craniofacial skeleton, smooth muscle, skin pigmentation, and multiple ocular and periocular structures. Indeed, abnormalities in neural crest development cause craniofacial defects and ocular anomalies, such as Axenfeld-Rieger syndrome and primary congenital glaucoma. Thus, understanding the molecular regulation of neural crest development is important to enhance our knowledge of the basis for congenital eye diseases, reflecting the contributions of these progenitors to multiple cell lineages. Particularly, understanding the underpinnings of neural crest formation will help to discern the complexities of eye development, as these NCCs are involved in every aspect of this process. In this review, we summarize the role of ocular NCCs in eye development, particularly focusing on congenital eye diseases associated with anterior segment defects and the interplay between three prominent molecules, PITX2, CYP1B1, and retinoic acid, which act in concert to specify a population of neural crest-derived mesenchymal progenitors for migration and differentiation, to give rise to distinct anterior segment tissues. We also describe recent findings implicating this stem cell population in ocular coloboma formation, and introduce recent evidence suggesting the involvement of NCCs in optic fissure closure and vascular development.

Sox4 regulates choroid fissure closure by limiting Hedgehog signaling during ocular morphogenesis

SoxC transcription factors play critical roles in many developmental processes, including neurogenesis, cardiac formation, and skeletal differentiation. In vitro and in vivo loss-of-function studies have suggested that SoxC genes are required for oculogenesis; however the mechanism was poorly understood. Here, we have explored the function of the SoxC factor Sox4 during zebrafish eye development. We show that sox4a and sox4b are expressed in the forebrain and periocular mesenchyme adjacent to the optic stalk during early eye development. Knockdown of sox4 in zebrafish resulted in coloboma, a structural malformation of the eye that is a significant cause of pediatric visual impairment in humans, in which the choroid fissure fails to close. Sox4 morphants displayed altered proximo-distal patterning of the optic vesicle, including expanded pax2 expression in the optic stalk, as well as ectopic cell proliferation in the retina. We show that the abnormal ocular morphogenesis observed in Sox4-deficient zebrafish is caused by elevated Hedgehog (Hh) signaling, and this is due to increased expression of the Hh pathway ligand Indian Hedgehog b (ihhb). Consistent with these results, coloboma in sox4 morphants could be rescued by pharmacological treatment with the Hh inhibitor cyclopamine, or by co-knockdown of ihhb. Conversely, overexpression of sox4 reduced Hh signaling and ihhb expression, resulting in cyclopia. Finally, we demonstrate that sox4 and sox11 have overlapping, but not completely redundant, functions in regulating ocular morphogenesis. Taken together, our data demonstrate that Sox4 is required to limit the extent of Hh signaling during eye development, and suggest that mutations in SoxC factors could contribute to the development of coloboma.

Bilateral chorioretinal coloboma discovered with ultra-wide field retinal imaging

Uveal coloboma results from incomplete closure of the optic cup fissure. While conducting an evaluation of a new ultra-wide field retinal imaging camera (Optomap), which provides a view of the fundus up to 200° at one time without mydriasis, we discovered a case of bilateral chorioretinal coloboma in a 21-year-old student. The lesion was located in the midperiphery of each eye less than 2 disc diameters (DD) below the optic disc in the inferonasal quadrants. The size of the coloboma in the right eye was 1.8 DD in height and 1.3 DD in width, while the left lesion was 2.4 DD in height and 2.6 DD in width. The subject was totally asymptomatic and without any complication such as retinal detachment or choroidal neovascularization, which often accompany this type of lesion. The visual field of each eye displayed an absolute scotoma corresponding to the size and location of the coloboma. No management was necessary but the subject was advised to report for visual examination at regular intervals because complications can occur at any age.

Intrapleural chemo- and hyperthermotherapies for malignant pleural effusion: a randomized prospective study

OBJECTIVE

The current prospective randomized study was designed to evaluate the safety and efficacy of combined intrapleural cisplatin and OK-432 (picibanil) plus hyperthermotherapy in patients with malignant pleural effusion (MPE).

METHODS

A total of 358 patients with MPE due to end-stage malignancies were enrolled and randomly divided into two groups, A and B: the intrapleural combination of cisplatin and OK-432 with hyperthermotherapy (n = 179) or without hyperthermotherapy (n = 179), respectively. Mild toxicities such as nausea, vomiting or anorexia, bone marrow depression, and pyrexia were similar in both groups.

RESULT

Patients in Group A (with hyperthermotherapy) showed a significantly higher overall response (93.4%) compared to those in Group B (79.8%, χ(2) = 43.11, p < .05). The median survival time for patients in Group A and Group B were 8.9 and 6.2 months, respectively (p > .05). After treatment, the quality of life scores were significantly increased in both groups as compared to prior treatment (p < .05).

CONCLUSION

In conclusion, our study suggests that combined intrapleural cisplatin and OK-432 followed by hyperthermotherapy are more effective in the control of MPE and improve patients' quality of life.

Choroidal neovascularization associated with coloboma of the choroid: a series of three cases

Choroidal neovascularization (CNV) is a rare complication associated with coloboma of the choroid. We describe three cases of coloboma choroid where there was loss of vision due to CNV development at the edge of the coloboma. One was managed by photodynamic therapy alone and two were managed by a combination of reduced fluence PDT and intravitreal bevacizumab. Significantly we noted that one treatment session was sufficient to achieve regression of the CNV and improvement in visual acuity.

Ranibizumab for coloboma-related choroidal neovascular membrane in a child

Optic nerve and retinochoroidal coloboma are caused by incomplete closure of the embryonic fissure during fetal development.(1) Affected patients carry a risk for retinal detachment and less so for choroidal neovascular membranes (CNVM) secondary to the altered anatomy. Because of the rarity of this condition and the even more unusual occurrence of such complications, there are only a few case reports on the treatment of coloboma-related CNVM. Herein we report the results of ranibizumab and laser photocoagulation for coloboma-related CNVM in a child.

Ocular features of CHARGE syndrome

PURPOSE

To detail the presence and severity of ocular and cranial nerve abnormalities found in individuals with CHARGE syndrome in a distinct geographic area.

METHODS

Nine individuals with CHARGE syndrome from Maritime Canada identified from a Canadian database were prospectively examined. Structural and sensorial defects associated with functional visual deficits were defined with ophthalmic and neurological evaluation.

RESULTS

Consistent with current diagnostic criteria and the literature, colobomas were the major ophthalmic manifestation. These were typically bilateral chorioretinal colobomas involving the optic nerve. All subjects had bilateral severe sensorineural deafness (cranial nerve VIII), and 8 of 9 (89%) had facial nerve (cranial nerve VII) involvement (7 of 9 had unilateral involvement; 1 of 9 had bilateral involvement). Unique to this group of participants were the findings of anisometropia in 8 of the 9 (89%) patients, severe myopic astigmatism in 13 of the 18 eyes (72%), and limited elevation in adduction in 3 of 9 (33%) participants. Associated findings were strabismus, cataracts, microcornea, keratopathy, staphyloma, reduced stereopsis, superior visual field defects, and reduced visual acuity.

CONCLUSIONS

The presence of coloboma plus another CHARGE feature warrants further investigation, including genetic screening for the CHD7 gene. Early recognition and management of sensory problems (visual, auditory, and vestibular) are crucial to ensure best psychomotor and cognitive development.

Clinical Feature Analysis of Congenital Optic Nerve Abnormalities

PURPOSE

We investigated the clinical characteristics and associated ocular and systemic anomalies in young children with congenital optic nerve abnormalities, and evaluated the therapeutic results of treatment for strabismus and amblyopia.

METHODS

A retrospective study was conducted using the medical records of patients who were diagnosed with congenital optic nerve abnormalities in our hospital between 1995 and 2004.

RESULTS

This study involved 72 eyes of 51 young children (M : F = 25 : 26); 21 of these patients (41.2%) had bilateral abnormalities. The types and percentages of each abnormality were as follows: optic nerve hypoplasia, 47%; optic disc coloboma, 31.4%; morning glory syndrome, 11.8%; and myelinated nerve fiber, 9.8%. The first clinical manifestations noticed by parents were strabismus and decreased visual acuity. Occlusion therapy was carried out in 16 patients, and the visual acuities of two patients were improved by more than two lines of the Early Treatment Diabetic Retinopathy Study visual acuity chart. Accompanying strabismus was found in 70.6% of the patients; 14 patients underwent strabismic surgery, and 10 of these patients (41.2%) maintained a stable angle.

CONCLUSIONS

The most common congenital optic nerve abnormality was optic nerve hypoplasia, and the associated systemic abnormalities found were optic nerve hypoplasia and disc coloboma. Patients with congenital optic nerve abnormalities usually have a generally poor visual prognosis, but we emphasize the importance of treatment for associated strabismus and amblyopia.

Ocular coloboma: a reassessment in the age of molecular neuroscience

Congenital colobomata of the eye are important causes of childhood visual impairment and blindness. Ocular coloboma can be seen in isolation and in an impressive number of multisystem syndromes, where the eye phenotype is often seen in association with severe neurological or craniofacial anomalies or other systemic developmental defects. Several studies have shown that, in addition to inheritance, environmental influences may be causative factors. Through work to identify genes underlying inherited coloboma, significant inroads are being made into understanding the molecular events controlling closure of the optic fissure. In general, severity of disease can be linked to the temporal expression of the gene, but this is modified by factors such as tissue specificity of gene expression and genetic redundancy.