Dominant inheritance of optic pits

Long-term outcomes of autologous platelet treatment for optic disc pit maculopathy

PURPOSE

Optic disc pits (ODPs) are rare congenital cavitary abnormalities of the optic nerve head, which can lead to serous macular detachments. The aim of this study was to evaluate the long-term efficacy of pars plana vitrectomy (PPV) combined with autologous platelet concentrate (APC) for the treatment of optic disc pit maculopathy (ODP-M).

METHODS

A retrospective analysis was performed on eleven eyes of ten patients with ODP-M, who received PPV combined with APC. Nine eyes operated primary, four of which had a repeat surgery also with injection of APC and two eyes underwent a rescue surgery, after they have been operated in another eye center without APC. Morphological and functional results were the main outcome parameters, determined by optical coherence tomography (OCT) and best-corrected visual acuity (BCVA), respectively.

RESULTS

The mean duration of visual loss before surgery was 4.7 ± 3.89 months (range 0-12 months). The mean BCVA increased significantly from 0.82 ± 0.33 logMAR (range 0.4-1.3) preoperatively to 0.51 ± 0.36 logMAR (range 0-1.2) at the last examination (p = 0.0022). A significant morphological improvement was also noticed with decrease of the mean foveal thickness from 935.82 ± 248.48 µm (range 559-1400 µm) preoperatively to 226.45 ± 76.09 µm (range 110-344 µm) at the final examination (p < 0.0001). The patients were followed-up for a mean 65.36 ± 48.81 months (range 1-144 months). Two eyes developed postoperatively a retinal detachment. Cataract surgery was performed in 5 eyes during the follow-up period.

CONCLUSION

Our study demonstrated that PPV with APC can improve functional and morphological outcomes, both as a primary and a rescue therapy, without any recurrence over a long follow-up period. To the best of our knowledge, this was the longest observation period regarding the use of APC in treatment of ODP-M.

Minimally invasive procedure for optic disc pit maculopathy: vitrectomy with scleral plug and analysis on pattern of resolution

Optic disc pit maculopathy (ODP-M) is a rare complication of optic disc pit which can cause irreversible visual impairment. The aim of this study is to evaluate the anatomical and functional outcomes and pattern of resolution of ODP-M following vitrectomy with posterior vitreous detachment (PVD) induction and scleral tissue plug for treatment of ODP-M without ILM peeling, laser or use of long term gas/tamponade or head positioning. This retrospective study included 7 patients with ODP-M, meeting the inclusion criteria. Patients were followed up for 6 months. Complete anatomical success was defined as "Total resolution of all the fluid in retinal compartments". All of the patients had complete resolution of the optic pit maculopathy following surgery. The mean duration for complete resolution was 18.3 weeks. Pattern of resolution of ODP-M was found to be resolution of the subretinal fluid (SRF) followed by disappearance of the retinoschitic lesions (RL) and finally disappearance of macular edema (ME). The proposed minimally invasive procedure (MIP) can produce comparably good and equally reliable results for the treatment of ODP-M.

A Classical Presentation of Optic Disc Pits With Complex Maculopathy

A rare congenital abnormality of the optic disc, known as the optic disc pit (ODP), can cause progressive vision loss when it is associated with maculopathy. Only 15% of ODP cases are bilateral, with a reported incidence of 1 in 11,000 cases and with no gender differentiation. A 56-year-old woman presented in the outpatient department with a history of gradual painless diminution of vision in the right eye for one year. On ocular examination of the right eye, the patient has a vision of counting finger 1 m not improving with pinhole, and anterior segment evaluation is within normal limits. On fundus examination, we could appreciate a grayish, white small hypopigmented depression present in the inferotemporal part of the optic disc suggestive of ODP and edema present in the inferior half of the macula along with cystoid macular edema. The fundus photo of the right eye was suggestive of inferotemporal ODP in the right eye and normal fundus in the left eye. Optical coherence tomography (OCT) of the right eye showed inferotemporal ODP connecting with the subarachnoid space of the optic nerve. The macula showed diffuse edema extending from disc to macula, neurosensory detachment, macular schisis, and cystoid macular edema. We report a case of unilateral ODP maculopathy (ODP-M), which is a congenital anomaly of the optic nerve head (ONH) located at the inferotemporal part of the optic disc with multilayered separation involving all retinal layers and connecting with the subarachnoid space, as seen on OCT.

Optic Pit Maculopathy: Clinical Features and Management Options

Purpose of Review

In this article, we review the pathogenesis, clinical features, imaging modalities and latest management options for optic pit maculopathy (OPM).

Recent Findings

The pathogenesis of OPM remains to be unclear, but imaging tools such as optical coherence tomography (OCT) and OCT angiography are enhancing our knowledge. Observation continues to be the best management strategy for patients with good visual acuity, and many cases have demonstrated spontaneous resolution. For more advanced, progressive vision loss, treatment options involving vitrectomy can be considered and discussed with the patient. Supplementary techniques to vitrectomy have been reported in small studies with relative success such as glial tissue peeling, inverted internal limiting membrane flap, optic pit plugging, and retinal fenestration.

Summary

While there are multiple treatment options available for OPM, there is no consensus on the technique and surgical timing. Individual patient factors and the risks-benefits of treatment must be taken into account in guiding management. Larger clinical trials will further assist in decision making for treating OPM.

Familial Optic Disc Pits in 2 Father-Son Pairs: Clinical Features and Genetic Analysis

Congenital optic disc pits (ODPs) are well-circumscribed depressions within the optic disc. Thought to arise from anomalous closure of the optic fissure during embryonic development, they are now considered to lie on a broader spectrum of congenital optic disc anomaly (CODA). An increasing number of reports describe clustering of these cases within families, suggesting that inherited genetic elements play a role in disease predisposition. Here, we highlight the clinical features of 2 sets of father-son pairs affected with ODPs and provide preliminary molecular genetic analysis. Subjects underwent complete ophthalmological examination and imaging. In addition, whole-exome sequencing was carried out following informed consent. The resulting datasets were examined for potentially causal genetic variants, both in genes already known to be linked to CODA as well as those likely to lie in the same or similar genetic pathways. In this instance, no unambiguously causal variants were identified. This case series highlights the familial inheritance of ODPs, adding to the existing body of literature supporting an underlying genetic cause for this rare clinical entity. The inclusion here of specific molecular findings raises the hope that the genetic pathophysiology underlying rare entities like ODPs might be clarified in the future by the addition of similarly molecular-documented reports.

Surgical outcomes in patients with optic disc pit maculopathy: does peeling the ILM lead to better outcomes?

PURPOSE

Optic disc pits (ODPs) are rare congenital anomalies. Several patients develop optic disc pit maculopathy (ODP-M): visual impairment caused by intra- and/or subretinal fluid. Treatment mode remains controversial. This study was designed to investigate the effectiveness of pars plana vitrectomy (PPV) and gas tamponade with or without internal limiting membrane (ILM)-peeling in improving visual acuity and reducing subretinal fluid in ODP-M patients.

METHODS

We retrospectively reviewed the charts of 16 patients who underwent surgery for ODP-M from 2002-2015. Six patients underwent PPV with gas tamponade (group 1); ten patients additionally received ILM-peeling (group 2). Pre- and postoperative visual acuity and central retinal thickness (CRT) were compared between groups, as well as retinal morphology and the number of secondary vitrectomies and complications.

RESULTS

Median visual acuity improved by 2 ETDRS lines in both groups (p = 0.713, Mann-Whitney U test). Median CRT decreased by 426.5 µm and 460 µm (p = 0.931). One patient in group 1 underwent repeat vitrectomy for persistent retinoschisis. Three patients in group 2 required repeat vitrectomy: two to treat a macular hole, one for peripheral retinal holes with retinal detachment.

CONCLUSION

In our cohort, PPV with gas tamponade proved to be an effective first-line treatment for ODP-M. Additional ILM-peeling did not give a significant benefit in this study.

Optic Disc Pit Maculopathy - Case Series, Clinical Approach, and Management

PURPOSE

The purpose of this study was to analyze the diagnostic and therapeutic approach of five cases with optic disc pit (ODP) maculopathy.

MATERIALS AND METHODS

This was a retrospective study of five patients diagnosed with ODP maculopathy. Four of these cases had unilateral involvement, whereas one case had bilateral findings. The medical notes of these individuals were reviewed in order to record the presenting symptoms, clinical signs, visual acuity (VA), imaging, management, and the final visual outcome on their last follow-up appointment.

RESULTS

The first patient (53-year-old female) underwent a left pars plana vitrectomy (PPV) combined with inner retinal fenestration, endolaser, and perfluoropropane (C3F8) gas tamponade and her VA improved from 6/24 to 6/9 Snellen. A focal retinal laser treatment was carried out on our second patient leading to decrease of the subretinal fluid but had a poor visual outcome due to the underlying secondary glaucoma from iris melanoma treatment in the past. The third patient was an asymptomatic 7-year-old girl in which the maculopathy resolved spontaneously without any surgical intervention with a final VA of 6/5. The fourth and fifth patients were asymptomatic with good vision in both eyes and were, therefore, only monitored with follow-ups.

CONCLUSION

ODP maculopathy remains a challenging clinical entity for a vitreoretinal surgeon. The current management for ODP maculopathy involves surgical procedures with PPV being a common treatment of choice. Spontaneous resolution of ODP maculopathy has also been reported. Our study highlights the contrasting management that can be adopted in the treatment of ODP maculopathy, and there is not one definite treatment for this condition.

[Macular changes in optic disc pits-Optic disc pit maculopathy (ODP-M) : Pathophysiology and possibilities of surgical treatment]

An optic disc pit is a rare congenital abnormality of the optic nerve, which in most cases presents as a unilateral finding. Clinically, a greyish oval excavation is seen, most commonly on the temporal side of the optic nerve disc. The optic disc pit alone normally does not lead to substantial symptoms or functional limitations; however, when a maculopathy with intraretinal and/or subretinal fluid and additional other morphological changes in the macula occur, this leads to a decrease in visual acuity. With spectral domain optical coherence tomography (SDOCT) it is possible to identify the various forms of expression, which show different natural courses. Especially the presence of subretinal fluid and defects in the outer retinal layers have a poor prognosis and have the highest risk for further deterioration. Spontaneous resolution can occur but is rare. Observation is recommended in the first step. In cases of progression or pronounced deterioration, surgical intervention is indicated. Many different techniques have been proposed but there is no gold standard at the moment. Most of the surgical approaches comprise pars plana vitrectomy with peeling of the internal limiting membrane (ILM) and gas endotamponade. Newer methods, such as the ILM flap technique also show good results. Generally, it is important to know that postoperative healing and resorption of the fluid often take a long time period of up to 1 year or even longer.

Optic disk pits and optic disk pit maculopathy: A review

Optic disk pit, one of the optic disk cavitary anomalies, is generally congenital and unilateral and occurs equally in males and females. Optic disk pit maculopathy is characterized by intraretinal and subretinal fluid at the macula, causing visual deterioration. The origin of the macular fluid and the mechanism of transition to the subretinal space in optic disk pit maculopathy pathophysiology are not yet fully understood. With the evolution of imaging modalities, especially optic coherence tomography, our knowledge of this disorder continues to increase. Although many different treatments have been tried, there is no consensus on the most effective.

Optic Disc Pit Maculopathy: A Two-Year Nationwide Prospective Population-based Study

PURPOSE

To identify the incidence, presenting features, treatment, and clinical course of optic disc pit maculopathy (ODPM) in the United Kingdom (UK).

DESIGN

A 2-year nationwide prospective population-based study.

SUBJECTS

All new incident cases of ODPM presenting to UK ophthalmologists using the British Ophthalmic Surveillance Unit monthly reporting system.

METHODS

All reporting ophthalmologists were sent an initial questionnaire requesting data on previous medical and ophthalmic history, presentation details, investigation findings, and management. A further questionnaire was sent at 12 months post diagnosis to ascertain further outcome data.

MAIN OUTCOME MEASURES

Visual acuity at initial presentation, at 1 year, and after any intervention. Foveal involvement and optical coherence tomography (OCT) findings, including retinal layers affected, and the location and size of the optic disc pit. Management, including observation, vitrectomy, and associated procedures.

RESULTS

There were 74 confirmed new cases, giving an annual incidence of approximately 1 per 2 million. Complete data were available on 70 patients (70 eyes) at baseline and 68 after 1 year. There were 35 (50%) female patients with a mean age of 35 years (range, 3-82 years). Visual acuity at baseline ranged from 6/5 to hand movements. In 43 patients (61%) subretinal fluid (SRF) was present, whereas 27 (39%) had intraretinal fluid only. The presence of SRF was associated with worse vision and foveal involvement. Of the 53 eyes initially observed with 1-year follow-up, 10 (19%) deteriorated and 9 (16%) improved on OCT; eyes with SRF were more likely to worsen and those without SRF were more likely to improve. Fifteen of the 70 patients (21%) at baseline had primary surgery and a further 10 had deferred surgery within 1 year of presentation; 19 of these 25 eyes (76%) showed anatomic success with a dry fovea at 1 year of follow-up, and 15 (60%) had a greater than 0.1 logMAR improvement in visual acuity.

CONCLUSION

The incidence and presenting features of ODPM were defined. Patients with SRF had worse vision and were more likely to deteriorate than patients with intraretinal fluid only. Surgery was anatomically successful in 75% of cases. Patients without SRF tended to remain stable with observation.

Congenital anomalies of the optic disc: insights from optical coherence tomography imaging

PURPOSE OF REVIEW

Congenital anomalies of the optic nerve are rare but significant causes of visual dysfunction in children and adults. Accurate diagnosis is dependent on a thorough funduscopic examination, but can be enhanced by imaging information garnered from optical coherence tomography (OCT). We review common congenital optic nerve anomalies, including optic disc pit, optic nerve coloboma, morning glory disc anomaly, and hypoplasia of the optic nerve, review their systemic associations, and discuss insights from OCT imaging.

RECENT FINDINGS

Optic disc pits are a result of a defect in the lamina cribrosa and abnormal vitreomacular adhesions have been shown to cause maculopathy. In patients with optic nerve colobomas, OCT can be instrumental in diagnosing choroidal neovascularization, a rare but visually devastating complication. The pathogenesis of morning glory disc anomaly has been more clearly elucidated by OCT as occurring from a secondary postnatal mesenchymal abnormality rather than only the initial neuroectodermal dysgenesis of the terminal optic stalk in isolation. OCT studies of optic nerve hypoplasia have demonstrated significant thinning of the inner and outer retinal layers of the perifoveal region and thicker layers in the fovea itself, resulting in a foveal hypoplasia-like pathology, that is, significantly correlated to poorer visual outcomes.

SUMMARY

OCT provides detailed in-vivo analysis of these anatomic anomalies and their resulting pathologies, shedding new insights on the pathogenesis, diagnosis, and potential visual outcomes of these conditions in children. Further study employing OCT to elucidate structure-function relationships of congenital optic nerve anomalies will help expand the role of OCT in clinical practice related to diagnosis, prognosis, and management of these entities.

Intrafamilial heterogeneity of congenital optic disc pit maculopathy

BACKGROUND

Optic disc pit is a very rare clinical entity. The main complication of this condition is the maculopathy. Report of cases: A 40-year-old Caucasian man and his 6-year-old daughter underwent a complete ophthalmological examination. In both cases ophthalmoscopy examination showed a bilateral white-yellow oval depression in the optic disc. Optical coherence tomography showed maculopathy with different degrees of severity in the two cases. Microperimetry and multifocal-electroretinography showed different degrees of retinal dysfunction in both cases. Molecular genetic analysis was performed and the possible pathogenic role of the MIR204 gene was excluded.

DISCUSSION

The findings of our familial cases support the hypothesis that optic disc pit associated with maculopathy could be a genetic disease with an autosomal dominant inheritance pattern. Optical coherence tomography is the most helpful diagnostic tool to assess maculopathy associated with optic disc pit. Microperimetry and multifocal-electroretinography are useful for the diagnosis of macular dysfunction in the early stages, and for the prognosis and follow-up of optic disc pit-maculopathy which is the main cause of visual impairment in these patients. Furthermore, in consideration of the variable expressivity and disease severity reported in our cases, genetic anticipation may be hypothesized.

Familial Disorders of the Optic Disc: Presentation of a Mother and Daughter and Review of the Literature

Optic disc pit and optic nerve coloboma are examples of congenital optic disc abnormalities. Although optic nerve coloboma can be inherited in an autosomal dominant fashion, no conclusive link has been found in the case of optic disc pit as an autosomal dominant disease. We describe two cases: a daughter with an optic disc pit complicated by maculopathy and her mother with a congenitally abnormal optic disc complicated by peripapillary choroidal neovascularisation.

Optic disc pit maculopathy: when and how to treat? A review of the pathogenesis and treatment options

Optic disc pit (ODP) is a rare congenital anomaly of the optic disc, which can be complicated by a maculopathy associated with progressive visual loss. Optic disc pits are usually unilateral and sporadic in occurrence, and the development of maculopathy is unpredictable with no known triggers. Optic disc pit maculopathy (ODP-M) is characterized by intraretinal and subretinal fluid at the macula, causing visual deterioration. The source of this fluid is still unclear, and several competing theories have suggested it may be vitreous fluid, cerebrospinal fluid, leakage from blood vessels at the base of the pit or leakage from the choroid. The mechanism of pathogenesis of ODP-M has not been fully elucidated, but vitreous liquefaction and traction and pressure gradients within the eye have been implicated to be involved. There are no clear guidelines on the management of patients with ODP-M, and numerous techniques have been described, including laser photocoagulation, intravitreal gas injection, macular buckling and pars plana vitrectomy with many different modifications. The majority of reports describe small series, and as there are no comparative studies there is no consensus regarding the optimal treatment for ODP-M. This review discusses the literature on the possible sources of fluid and mechanisms of pathogenesis in ODP-M, as well as the wide array of treatment modalities and their results. Based on these, a set of recommended key concepts for the timing and choice of treatment for these challenging are presented.

Congenital abnormalities of the optic nerve: from gene mutation to clinical expression

Optic nerve malformations are common causes of congenital blindness and are recognized with increasing prevalence. The importance of identifying these malformations lies not only in determining the cause and level of visual impairment, but also in looking for associated treatable or life threatening systemic conditions. A number of genetic mutations have been identified in the development of optic disc anomalies, such as ones in PAX2 or PAX6. Recent advances in genetic testing like array comparative genomic hybridization allow the detection of microdeletions that were previously difficult or impossible to identify.

Familial cavitary optic disk anomalies: clinical features of a large family with examples of progressive optic nerve head cupping

PURPOSE

To describe a multigenerational family with autosomal dominant inheritance of cavitary optic nerve head (ONH) anomalies and abnormal ONH vasculature.

DESIGN

Description of a single family with inherited eye disease.

METHODS

A four-generation pedigree was investigated. Examination included visual acuity, slit-lamp biomicroscopy, intraocular pressure (IOP) measurement, and ophthalmoscopy. Visual fields and fundus photography were obtained when possible.

RESULTS

Seventeen clinically affected individuals and two obligate carriers were identified. Most (64.7%) affected persons had bilateral involvement. Visual acuity in affected eyes ranged from 20/20 to no light perception. Although the appearance of affected nerves varied greatly, most lacked a well-formed central retinal artery and instead had multiple radial cilioretinal arteries. Prominent cupping was seen in most affected nerves. Four individuals for whom information was available were treated for glaucoma, but none had documented elevated IOP. Four eyes of two patients demonstrated progressive ONH cupping at normal IOPs. Nine (56.3%) of the 16 individuals for whom we had data had evidence of serous macular detachments; five of these had bilateral macular disease.

CONCLUSIONS

A large family with autosomal dominant inheritance of cavitary ONH anomalies and abnormal vasculature is presented. Clinical phenotypes varied markedly. Progressive ONH cupping was documented in four eyes of two patients. Genetic linkage analysis of this family has identified the chromosomal location of a gene responsible for ONH development. This may provide insight into the pathogenesis of glaucomatous ONH damage.

Familial cavitary optic disk anomalies: identification of a novel genetic locus

PURPOSE

To identify the chromosomal location of the gene involved in the pathogenesis of cavitary optic disk anomalies in a large pedigree with autosomal dominant inheritance of disease.

DESIGN

Linkage analysis of a pedigree affected with cavitary optic disk anomalies.

METHODS

Optic disk photographs were examined for the presence of cavitary optic disk anomalies. Sixteen affected family members and one obligate carrier were identified and studied with linkage analysis using both microarrays of single nucleotide polymorphisms (SNPs) and short tandem repeat polymorphism (STRP) markers.

RESULTS

Multipoint linkage analysis of SNP genotypes yielded a maximum nonparametric logarithm of the odds (LOD) score of 21.7 with markers located on chromosome 12q. Linkage was confirmed with 16 STRP markers in the 12q region. A maximum two-point LOD score of 4.06 (theta = 0) was obtained with marker D12S1700. The disease interval defined by observed recombinants is 9.1 cM, which corresponds to 13.5 Mbp. Three candidate genes (GDF-11, NEUROD4, and WIF1) in the chromosome 12q locus were evaluated as possible disease-causing genes. No mutations were detected in the coding sequence of these genes.

CONCLUSIONS

The discovery of the chromosomal location of a gene responsible for cavitary optic disk anomalies is a key step in identifying the genetic basis of this condition and ultimately may provide important insight into the pathogenesis of more common optic nerve diseases such as normal-tension glaucoma and primary open-angle glaucoma (POAG).

Uveal coloboma: clinical and basic science update

PURPOSE OF REVIEW

To integrate knowledge on the embryologic and molecular basis of optic fissure closure with clinical observations in patients with uveal coloboma.

RECENT FINDINGS

Closure of the optic fissure has been well characterized and many genetic alterations have been associated with coloboma; however, molecular mechanisms leading to coloboma remain largely unknown. In the past decade, we have gained better understanding of genes critical to eye development; however, mutations in these genes have been found in few individuals with coloboma. CHD7 mutations have been identified in patients with CHARGE syndrome (coloboma, heart defects, choanal atresia, retarded growth, genital anomalies, and ear anomalies or deafness). Animal models are bringing us closer to a molecular understanding of optic fissure closure.

SUMMARY

Optic fissure closure requires precise orchestration in timing and apposition of two poles of the optic cup. The relative roles of genetics and environment on this process remain elusive. While most cases of coloboma are sporadic, autosomal dominant, autosomal recessive, and X-linked inheritance patterns have been described. Genetically, colobomata demonstrate pleiotropy, heterogeneity, variable expressivity, and reduced penetrance. Coloboma is a complex disorder with a variable prognosis and requires regular examination to optimize visual acuity and to monitor for potential complications.

Stratus Optical Coherence Tomography for Evaluating Optic Disc Pits Associated with Maculopathy Before and After Vitrectomy: Two Case Reports

Optic disc pit (ODP) can be either congenital or acquired. Congenital ODP is typically unilateral, and the visual acuity and visual field are normal unless associated with macular serous detachment, which occurs in about 25-75% of cases. Acquired ODP is known as an important risk factor for progressive visual field loss in glaucoma. The fundus finding of congenital ODP includes oval depression involving the optic disc, with or without macular serous detachment. We used third-generation Stratus optical coherence tomography (Straus OCT) to investigate the possible pathogenesis of ODP associated with maculopathy and to monitor the anatomic changes before and after treatment.

Intraocular surgery for optic nerve disorders

This article discusses two current indications for intraocular surgery for optic nerve conditions. The first topic is macular detachment in association with congenital optic disc pit, and includes a review of the theories of pathogenesis and management options including our own experience of treatment with vitrectomy and gas tamponade. In addition, the histopathological findings of a new case of optic disc pit with serous macular detachment are presented, adding to the rare examples previously reported. The second subject is a radial optic neurotomy, a recently advocated treatment for central retinal vein occlusion, which, despite its controversial nature, is gaining in popularity.

Progressive optic nerve cupping and neural rim decrease in a patient with bilateral autosomal dominant optic nerve colobomas

PURPOSE

To document progressive optic nerve cupping and neural rim decrease in a patient with normal intraocular pressures and bilateral autosomal dominant optic nerve colobomas.

METHODS

The ophthalmology records, stereoscopic fundus photographs, and visual fields of a 27-year-old woman with familial (autosomal dominant) optic nerve colobomas were reviewed. The appearance of the optic nerves was documented over a 13-year period (1985 to 1998).

RESULTS

Despite repeatedly normal intraocular pressures, the patient showed progressive optic nerve cupping and neural rim decrease in both eyes. Visual field testing was available over a 5-year period (1993 to 1998) and was abnormal, but no progression was seen.

CONCLUSIONS

This case of progressive cupping and neural rim decrease in a patient with autosomal dominant optic nerve coloboma in both eyes may provide insight into the optic nerve cupping associated with normal tension glaucoma. Careful follow-up of patients with optic disk colobomas or patients is indicated to detect possible optic nerve changes or field loss.

Renal-coloboma syndrome: a multi-system developmental disorder caused by PAX2 mutations

Optic nerve coloboma combined with renal disease, also called renal-coloboma syndrome ( # 120330 in McKusick's Mendelian Inheritance in Man Online, OMIM), a relatively recently characterized syndrome, results from autosomal dominant mutations in the PAX2 gene. Although renal-coloboma syndrome involves both ocular and renal anomalies, some patients are affected with vesico-ureteral reflux (VUR), high frequency hearing loss, central nervous system (CNS) anomalies, and/or genital anomalies, consistent with the expression of PAX2 in these tissues during development. We review here the clinical features of patients with renal-coloboma syndrome and PAX2 mutation. We also review the PAX2 mutations that have been reported to date, and discuss the possible effect of PAX2 mutations on normal development.

The prevalence of PAX2 mutations in patients with isolated colobomas or colobomas associated with urogenital anomalies

The PAX2 gene is mutated in patients with ocular colobomas, vesicoureteral reflux (VUR), and kidney anomalies (renal-coloboma syndrome, OMIM 120330). The three abnormalities which make up this syndrome also occur in isolation, but the causal genes are not known. PAX2 encodes a transcription factor of the paired box class of DNA binding proteins, important for the development of the urogenital tract, optic nerve and adjacent retina, inner ear, and CNS. In this paper we have investigated the prevalence of PAX2 mutations in patients with ocular colobomas, microphthalmos, or retinal anomalies, either in isolation or with associated urogenital anomalies. Using PCR-SSCP, most or all exons of PAX2 were examined in blood DNA from 99 patients who have either ocular anomalies alone or a combination of ocular and urogenital conditions. PAX2 mutations were not detected in patients with ocular colobomas, either in isolation or with associated abnormalities, except in one patient with typical renal-coloboma syndrome. We conclude that PAX2 mutations are unlikely to be common in patients with ocular colobomas in isolation or in patients with ocular colobomas and associated anomalies, except for patients with typical renal-coloboma syndrome where PAX2 is known to be the aetiological cause.