Macular colobomas in Leber's congenital amaurosis

Optical coherence tomography and fundus autofluorescence imaging in an infant with RD3-related leber congenital amaurosis

Background: Leber congenital amaurosis (LCA) is both genetically and phenotypically heterogeneous group of retinal disorder. Mutations in retinal degeneration 3 (RD3) have been reported as an infrequent cause of LCA which account for less than 1% of all known LCA cases. This case report provides Optical Coherence Tomography (OCT) and Fundus Autofluorescence (FAF) findings of an infant with LCA related to a mutation in RD3.Materials and Methods: Single retrospective case report.Results: TruSight One Expanded Sequencing Panel was applied to the patient on the Illumina NextSeq. Homozygous pathogenic variant (c.112 C > T, p.Arg38Ter) was detected in the RD3 gene. Well-demarcated central foveal atrophy was noted in the infrared imaging. FAF imaging showed perifoveal hyperautofluorescent ring and irregular hyperautofluorescence outside the vascular arcade. An arrest in foveal development and loss of outer retinal structure including outer nuclear layer, external limiting membrane, ellipsoid zone and interdigitation zone at the fovea were detected in the OCT imaging.Conclusion: This study indicates that RD3-related LCA has a very severe phenotype with foveal development arrest and very early loss of all photoreceptor layer and external limiting membrane at the fovea.

Late presentation of RPE65 retinopathy in three siblings

Purpose

Gene therapy for RPE65 retinopathy has been recently approved. The purpose of this study was to assess retinal structure and function in 3 siblings presenting with late-stage RPE65 retinopathy and to assess the unmet need for such therapy in Saudi Arabia.

Methods

Search of the retinal dystrophy registry at King Khaled Eye Specialist Hospital and clinical examination including multimodal retinal imaging, full-field electroretinography (ERG), dark adapted full-field stimulus sensitivity thresholds, and molecular genetic testing in 3 patients.

Results

Nine (9) patients were identified with biallelic RPE65 mutations, corresponding to a prevalence rate of 9/187 = 5% among early onset retinal dystrophies. Of these, 3 siblings (2 male and 1 female) with RPE65 retinopathy were assessed in detail, because of an unusual, late presentation. They were all over 30 years old at the time of their most recent visits and had non-recordable ERGs. The 2 male siblings presented with poor vision and paracentral loss of the inner segment ellipsoid (ISe) and focal attenuation of the outer nuclear layer (ONL) in the macula. On the other hand, the female sibling presented with 20/100 vision with preserved foveal ISe and intact ONL throughout the macula and significantly lower light sensitivity thresholds compared to her male siblings. A homozygous missense p.Arg91Trp mutation in RPE65 was identified in all. All patients were eligible for gene therapy, demonstrating a central retinal thickness of more than 100 microns on repeated examinations.

Conclusions

RPE65 retinopathy seems to be relatively common on the Arabian peninsula, and in addition it may be underdiagnosed. To the best of our knowledge, this is the first detailed presentation, including multimodal retinal imaging and electrophysiological assessment, of such patients from this region. Patients with late presentation of RPE65 retinopathy may be eligible for gene therapy, in terms of remaining retinal function and structural preservation. The therapeutic window of such therapy remains to be determined.

Electronic supplementary material

The online version of this article (10.1007/s10633-019-09745-z) contains supplementary material, which is available to authorized users.

Ocular disease in the cobalamin C defect: a review of the literature and a suggested framework for clinical surveillance

The association between combined methylmalonic acidemia and homocystinuria of cblC type (cobalamin C defect, cblC) and ocular disease is now well recognized, and is a significant component of morbidity and disability associated with the condition. In this review, through collation of historically reported cases of early- and late-onset cblC and previously unreported cases, we have attempted to characterize the epidemiology, clinical features, and pathomechanisms of individual ocular features of cblC. These data suggest that maculopathy and nystagmus with abnormal vision are extremely common and affect the majority of children with early-onset cblC, usually before school age; strabismus and optic atrophy are also seen at relatively high frequency. The timing of progression of macular disease may coincide with a critical period of postnatal foveal development. Maculopathy and retinal disease may be subclinical and show only partial correlation with the extent of visual deficits, and visual deterioration may be relentlessly progressive in spite of aggressive treatment of biochemical abnormalities. In later-onset forms of the disease, visual loss and ocular complications appear to be infrequent. Finally, we discuss investigational strategies in diagnosing and characterizing eye disease in individuals with cblC, explore possible therapeutic avenues that may attenuate progression and severity of eye disease, and propose a clinical surveillance guideline for monitoring progression of ocular disease in children and adults with cblC.

Longitudinal clinical course of three Japanese patients with Leber congenital amaurosis/early-onset retinal dystrophy with RDH12 mutation

PURPOSE

To report the longitudinal clinical course of three Japanese patients from two families with Leber congenital amaurosis/early-onset retinal dystrophy (LCA/EORD), and the results of next-generation DNA sequences on them.

PATIENTS AND METHODS

The patients were three Japanese children: a 4-year-old girl, a 6-year-old boy, and a 3-year-old girl. Patients 1 and 2 were siblings, and patient 3 was from an unrelated family. Standard ophthalmic examinations including perimetry, electroretinography, optical coherence tomography, and ultrasonography were performed on each patient. The patients were observed for 28, 16, and 10 years. Whole exomes of the patients and their non-symptomatic parents were analyzed using a next-generation sequence technique.

RESULTS

The decimal visual acuity varied between 0.07 and 0.6 at the initial visit and decreased to counting finger to hand motion in their teens. Funduscopy showed diffuse retinal and macular degeneration. During the follow-up period, a posterior staphyloma developed and the macular area became atrophic. Patient 1 developed cataracts in her early twenties. Genetic analysis revealed a homozygous A126V substitution in the RDH12 gene in all patients.

CONCLUSIONS

The three patients with LCA/EORD had a progressive decrease of their vision with the formation of a posterior staphyloma. This is the first report of Japanese patients with LCA/EORD with a RDH12 mutation.

Differential macular morphology in patients with RPE65-, CEP290-, GUCY2D-, and AIPL1-related Leber congenital amaurosis

PURPOSE

To evaluate genotypic and macular morphologic correlations in patients with RPE65-, CEP290-, GUCY2D-, or AIPL1-related Leber congenital amaurosis (LCA) using spectral-domain optical coherence tomography (SD-OCT).

METHODS

SD-OCT macular scans were performed in 21 patients, including 10 with RPE65, 7 with CEP290, 3 with GUCY2D, and 1 with AIPL1 mutations. An image processing software was used to manually draw segmentation lines by three observers. Lamellar structure was evaluated based on the number of retinal layers on segmented images. Total retinal thickness was measured at the central macular and perifoveal areas by using an automated algorithm.

RESULTS

All three patients with GUCY2D mutations (age range, 20-53 years) retained six retinal layers with visible photoreceptor inner/outer segment juncture (PSJ). However, the preservation of lamellar structures did not parallel better visual acuity. Patients with other mutations had poorly defined PSJ and disorganized retinal lamellar structures, where only one to three retinal layers could be observed. Patients with CEP290 mutations trended to have retention of the outer nuclear layer at the fovea and macular thickening, especially at younger ages. In patients with RPE65 (age range, 20-71 years) and AIPL1 mutations (age, 22 years), macular thickness was markedly decreased. Disorganization of retinal lamellar structures in the RPE65 group trended toward a worsening with increasing age.

CONCLUSIONS

Variations of macular microstructures were observed among LCA patients with different genotypes. Disorganization of retinal lamellar structure was generally age related. Preservation of retinal microanatomic structures may not be associated with better visual acuity.

EVALUATION OF GENOTYPE–PHENOTYPE ASSOCIATIONS IN LEBER CONGENITAL AMAUROSIS

PURPOSE

To describe the clinical phenotypes associated with various genotypes known to cause Leber congenital amaurosis (LCA).

METHODS

One hundred ten LCA patients were screened for various probable disease-causing gene sequence variations. Those patients with a probable disease-causing sequence variation in one of six genotypes were recalled for a follow-up examination. Evaluations included assessment of visual acuity, slit-lamp biomicroscopy, and dilated fundus examination. When possible, Goldmann perimetry was also performed.

RESULTS

Of the 37 LCA patients with suspected disease-causing sequence variations, 7 had an AIPL1 variation, 8, a CRB1 variation, 2, a CRX variation, 4, a GUCY2D variation, 11, an RPE65 variation, and 5, an RPGRIP1 variation. Across the 6 genotypes, we observed a wide range of visual acuities from 20/40 to no light perception. The widest range of vision was noted for patients with a CRB1 or RPE65 variation. Younger patients with an AIPL1 or RPGRIP1 variation were found to have severely reduced vision. Drusenlike deposits were more selectively observed in patients with mutations in the AIPL1, CRB1, RPE65, and RPGRIP1 genes, whereas focal regions of peripheral chorioretinal atrophy were observed only in patients with AIPL1 or RPE65 variations. Neurologic, intellectual, or psychomotor developmental delay was noted in 8.1% of our cohort.

CONCLUSIONS

There was considerable overlap of phenotypic expression in six genetic subtypes in our LCA cohort. However, phenotypic trends were noted in our patients' visual acuities and posterior segment findings within genotypes. These findings have practical value for genetic screening strategies for LCA patients based upon phenotype as well as for counseling patients on their visual prognosis.

Towards improved clinical characterization of Leber congenital amaurosis: neurological and systemic findings

Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophy that presents in infancy. LCA is both clinically and genetically heterogeneous. The aim of our study was to clarify the clinical aspects of LCA and to contribute to improved characterization of the disorder. We studied 40 children affected by LCA (mean age at first observation: 19 months, range: 8-50 months), who underwent a comprehensive evaluation that included: neurophthalmological evaluation, electroretinogram (ERG), and visual evoked potentials (VEPs), general and neurological examinations, developmental assessment using scales for visually impaired children, neuroradiological examinations, hepatic and renal function and metabolic investigations, brainstem auditory evoked potentials (BAEPs), EEG, and hand radiographs. Analyses of known LCA genes are ongoing. The subjects are still being followed up at 6-/12-month intervals. All the subjects fulfilled De Laey's criteria for LCA. The neurological examination was abnormal in 31 cases (hypotonia, ataxia with/without associated cerebellar signs). Cognitive development was normal in 24 cases, borderline in five, and subnormal in 11. Mild and nonspecific alterations on MRI were present in seven cases, and "molar tooth" sign in four; all the others had a normal neuroradiological picture. Among the subjects presenting with neurological signs, a subgroup (13 patients) emerged that was characterized by systemic (skin, kidney, liver) involvement. Our data confirm that LCA is a heterogeneous entity that can present as an isolated ocular manifestation, or in association with neurological and systemic abnormalities and support the need for a multidisciplinary approach to this entity and for genotype-phenotype studies.

Macular coloboma in siblings affected by different phenotypes of retinitis pigmentosa

Purpose To report the clinical association between macular coloboma (early-onset macular dystrophies/atrophic changes) and different phenotypes of retinitis pigmentosa (RP). Methods Three young-adult siblings, two males and one female, were retrospectively studied. These patients underwent two complete ophthalmologic examinations (27-month follow-up), including orthoptic evaluation, colour vision test, visual field, corneal topography, electronystagmography, fluorescein angiography, and electroretinography. Eye check, automated visual field test, and complete electroretinographic study were also conducted on other asymptomatic members of the same family. Results All symptomatic siblings were affected by manifest congenital nystagmus, poor visual acuity, and progressive visual field impairment in both eyes, bilaterally presenting macular coloboma associated with three different RP patterns: classic RP; mild dystrophy of the retinal pigment epithelium, associated with subnormal electroretinographic findings (subclinical form of RP); and sector RP. The ophthalmologic reports regarding their deceased father documented that he had suffered from the same alterations of ocular movements and visual performances diagnosing, in both eyes, extensive atrophic changes of the macular area completely surrounded by pigmented bone spicules (RP-type tapeto-retinal dystrophy). The other investigated relatives did not show any specific and/or significant ocular disorder. Conclusions In these three adult members of the same family, the concomitance between macular coloboma and different intrafamilial RP phenotypes is described. This association represents an autosomal dominant clinical entity, hitherto observed only in non familial sporadic cases.Eye (2004) 18, 421-428. doi:10.1038/sj.eye.6700689

RPGRIP1s with distinct neuronal localization and biochemical properties associate selectively with RanBP2 in amacrine neurons

RPGR and RPGRIP1 are molecular partners with vital roles in retinal function. Mutations in RPGR are implicated in heterogeneous retinal phenotypes, while those in RPGRIP1 lead to Leber congenital amaurosis. RPGR and RPGRIP1s differentially localize in photoreceptors among species. This may contribute to phenotype disparities among species bearing mutations in RPGR. However, it cannot account for the phenotype heterogeneity associated with RPGR- and RPGRIP1-linked mutations in the human. The existence of RPGRIP1 isoforms with distinct cellular, subcellular localizations and biochemical properties in the retina is shown. High mass RPGRIP1 isoforms, p175/p150, enriched in the outer segment (OS) compartment of photoreceptors are identified. The remaining isoforms are present across subcellular fractions, including nuclei and are soluble. The p175/p150 are predominantly sequestered in the cytoskeleton-insoluble fraction of OS and nuclei. In selective amacrine cells, and in the transformed photoreceptor line, 661W, RPGRIP1s localize at restricted foci to nuclear pore complexes and/or the vicinity of these. Among the nucleoporins, RPGRIP1 isoforms selectively associate in vivo with RanBP2 (Nup358). RPGRIP1s also decorate microtubules in 661W cells and occasionally form coiled-like inclusion bodies in the perikarya. These results support distinct but complementary functions of RPGRIP1 isoforms in cytoskeletal-mediated processes in photoreceptors and amacrine neurons, and may explain the Leber phenotype linked to RPGRIP1 mutations in humans. Moreover, the data implicate a role of RanBP2 in the pathogenesis of neuro(retino)pathies and as a docking station to mediate the nucleocytoplasmic shuttling of RPGRIP1s and their interaction with other partners in amacrine and 661W neurons.

Leber's congenital amaurosis: an update

Leber's congenital amaurosis (LCA) is a clinically and genetically heterogeneous disorder characterized by severe loss of vision at birth. It accounts for 10-18% of cases of congenital blindness. Some patients exhibit only blindness of retinal origin whereas others show evidence of a multi-systemic involvement. We review the literature relating to this severe disorder, highlighting unresolved questions, in particular the nature of the association of LCA with mental retardation and with systemic findings and syndromic pictures. In recent years, genetic advances in the diagnosis of LCA have opened up new horizons, also from a therapeutic point of view. A better understanding of this pathology would be valuable for paediatric neurologists.

Ocular colobomata

Ocular colobomata present diagnostic and therapeutic challenges in patients of all ages, but especially in young children. The "typical" coloboma, caused by defective closure of the fetal fissure, is located in the inferonasal quadrant, and it may affect any part of the globe traversed by the fissure from the iris to the optic nerve. Ocular colobomata are often associated with microphthalmia, and they may be idiopathic or associated with various syndromes. Types and severity of complications vary depending on the location and size of the colobomata. This article reviews the pathogeneses, categorization, genetic bases, differential diagnoses and management of ocular coloboma.

Congenital-onset central chorioretinal dystrophy associated with high myopia

We describe six siblings of a 12-member sibship affected with a macular dystrophy that is congenital in onset and is associated with progressive myopia. The age of these siblings ranged from 7 months to 19 years. The presenting feature was visual impairment and the best corrected visual acuity ranged between 1/60 and 6/36. Myopia ranged from -3.00 dioptres in the youngest to -10.50 dioptres in the second-eldest member. The macular lesions in our patients are characterised by a well-defined area of atrophy of choriocapillaris and retinal pigment epithelium. These lesions progressed with age in both size and depth. The extent of choroidal involvement in the lesions varied from only loss of superficial vasculature to sparing of large choroidal vessels as confirmed by fundus fluorescein angiography. One patient also exhibited bilateral Duane's syndrome (type III) and right unilateral ptosis. To the best of our knowledge such a fully established macular lesion presenting at the age of 6 months and associated with progressive myopia has never been described in literature.

Leber's congenital amaurosis associated with mitochondrial dysfunction

We report the case histories of two 6-month-old girls, both with young, nonconsanguineous parents, referred to us for suspected blindness. In both cases, Leber's congenital amaurosis was diagnosed. Due to persistently high lactic acid levels in blood, muscle biopsies were taken. Analysis of biopsies revealed that both patients had low levels of complex IV of the mitochondrial respiratory chain; one patient additionally had low levels of complex III. Microscopic and ultrastructural alterations of muscle, typically observed in mitochondrial disorders, were observed only in the second patient. These observations raise the possibility that at least some cases of Leber's congenital amaurosis may be due to alterations in the mitochondrial respiratory chain.

Bilateral macular coloboma and pigmented paravenous retinochoroidal atrophy

A patient had bilateral macular coloboma with aggregations of pigment clumps located perivascularly, predominantly paravenously, and in other parts of the retina. The Toxoplasma IgG antibody was negative. The diagnosis of bilateral macular coloboma with pigmented paravenous retinochoroidal atrophy was made and seemed to be a developmental abnormality in origin.

The natural history of Leber's congenital amaurosis. Age-related findings in 35 patients

The authors studied 35 patients with Leber's congenital amaurosis and assessed visual acuity, fundus appearance, and systemic findings. The patients were arbitrarily divided into five age groups. Visual acuities were comparable at all ages. Of 22 patients seen for follow-up examinations (mean length of follow-up, 5 years), vision worsened slightly in only 4 patients (3 with macular coloboma-like lesions and 1 with keratoconus). Fifty percent of retinal examinations in patients younger than 1 year of age were normal. With increasing age, retinal pigmentary changes became evident. All but four patients seen on more than one occasion developed progressive retinal/retinal pigment epithelium changes. Cataracts (5 patients) and keratoconus (3 patients) were present only in older patients (9 to 33 years of age). In Leber's congenital amaurosis, which probably comprises a number of genetically heterogenous conditions, visual acuity remains stable despite progressive retinal pigmentary changes. The subgroup of patients with macular colobomas, however, may develop progressive decrease in vision. Cataracts and keratoconus are additional factors contributing to visual impairment in older patients.

Linkage studies and mutation analysis of the PDEB gene in 23 families with Leber congenital amaurosis

The phenotype in the rd mouse is similar to the clinical presentation of Leber congenital amaurosis (LCA) in humans. Recently a nonsense mutation in the beta subunit of the cGMP phosphodiesterase (Pdeb) gene has been defined as the cause for the rd phenotype in the mouse and has raised the question as to whether mutations in the human PDEB gene might cause LCA. We have previously cloned and characterized the human homologue of the mouse Pdeb gene and have mapped it to chromosome 4p16.3. In this study, a total of 23 LCA families of various ethnic backgrounds have been investigated. Linkage analysis using highly polymorphic (CA)n microsatellites has excluded the PDEB gene as a cause for LCA in 6 families. In the remaining 17 families, we have searched for mutations in the 22 exons of the PDEB gene using single-strand gel electrophoresis (SSGE). Multiple exonic polymorphisms have been determined. However, no DNA changes in the PDEB gene have been identified in our study population which could be causative for the LCA phenotype.

Clinical spectrum of leber's congenital amaurosis in the second to fourth decades of life

Leber's congenital amaurosis is a type of congenital retinitis pigmentosa in which the fundus abnormalities are extremely variable and to some extent age dependent. Most cases are seen in infancy. The retinal, electroretinogram, and fluorescein angiographic findings are described in ten patients with Leber's congenital amaurosis who ranged in age from 13 to 36 years when first seen. All of the patients were from Honduras and were unrelated except for one pair (a brother and sister). The polymorphic appearance of the fundus is emphasized and is particularly striking in the siblings. A macular lesion (a bull's-eye maculopathy) not previously associated with Leber's congenital amaurosis is reported as a variant fundus appearance in this entity.

Dominant macular colobomata

Hereditary bilateral macular colobomata are not a consequence of an anomalous closure of the fetal fissure. Their extreme rarity, their lack of embryological explanation, and their morphologic similarity to postinflammatory congenital macular scars called the hereditary-malformative etiology of this entity in question. The authors describe a four generation family with seven affected members with isolated autosomal dominant bilateral macular colobomata.

The infant with nystagmus, normal appearing fundi, but an abnormal ERG

Many retinal disorders present during infancy with nystagmus, decreased vision, and normal-appearing fundi, but an abnormal ERG. The most common of these disorders are Leber's congenital amaurosis, achromatopsia, and congenital stationary night-blindness. Other disorders with similar ocular manifestations may be associated with a variety of life-threatening systemic abnormalities. This review describes the clinical, electrophysiological, and laboratory findings that can be used to distinguish among these conditions.

Follow-up and diagnostic reappraisal of 75 patients with Leber's congenital amaurosis

We reexamined 75 children in whom Leber's congenital amaurosis had been previously diagnosed. On review, 30 of these patients had an ocular or systemic disorder other than Leber's congenital amaurosis. The most common of these revised diagnoses were congenital stationary night blindness, achromatopsia, infantile-onset retinitis pigmentosa, Joubert's syndrome, Zellweger syndrome, and infantile Refsum's disease. Of the 45 patients with Leber's congenital amaurosis, mental retardation occurred in six patients, and visual deterioration in six patients. Leber's congenital amaurosis should only be diagnosed if other known ocular and systemic disorders have been carefully excluded.

Bilateral macular colobomas in Leber's congenital amaurosis

Two siblings with Leber's congenital amaurosis had bilateral macular colobomas, nystagmus, extinguished ERGs, and degenerative salt and pepper like changes in the fundus. They had non-recordable or non-meaningful visually evoked cortical potentials in response to both flash and pattern stimuli. The ophthalmic conditions were thought to be inherited as an autosomal recessive trait.

Retinal dystrophy and macular coloboma

Seven cases of retinal dystrophy associated with bilateral macular colobomata are presented. Two separate entities were found. The first is a congenital onset pigmentary retinopathy similar in electrophysiologic findings and symptoms to typical Leber's congenital amaurosis; the second appears to be a form of pregressive cone-rod dystrophy with pigmentary retinopathy. Review of the pertinant literature and clinical evidence suggest that both conditions are distinct entities inherited in the autosomal recessive manner.

Ophthalmologic and systemic manifestations of Alström's disease

Alström's syndrome consists of pigmentary retinopathy, diabetes, obesity, normal mental capacity, and sensorineural deafness. The early retinal findings are optic atrophy, salt-and-pepper pigment epithelial abnormalities, and marked vascular attenuation. Later in the disease process, diffuse areas of chorioretinal atrophy and large clumps of pigment develop. Severe visual loss in the first decade is characteristic and is an important point in the differential diagnosis. Clinically evident renal disease is a variable age-related phenomenon, and is probably the most frequent cause of death.

Bilateral macular dysplasia ('colobomata') and congenital retinal dystrophy

Three unrelated patients with bilateral macular dysplasia ('colobomata') with no relevant family history were found to have absent or substantially abnormal electroretinograms, implying that there was an associated retinal dystrophy. This may suggest that the macular lesions are associated with a global failure of retinal development, with a regional preponderance rather than a purely localised cause such as an intrauterine infection. It is important to distinguish between congenital infections such as toxoplasmosis and developmental macular colobomata, which have a somewhat similar ophthalmoscopic appearance as a cause of bilateral macular abnormalities seen in young children, since they have different implications for genetic advice and future ophthalmic care.

Yellowish flecks in Leber's congenital amaurosis

The fundus abnormalities of Leber's congenital amaurosis are extremely variable, from normal to salt-and-pepper changes to typical retinitis pigmentosa. A less commonly seen appearance is that of multiple, irregular shaped, yellowish white flecks deep in the midperipheral retina in a periarteriolar distribution. The nasal fundus as well as the posterior pole are spared. Such a case is presented along with a four-year follow-up together with the fluorescein angiographic findings. The flecks appear to be specific for this entity.

Acquired esotropia. A manifestation of Chiari I malformation

A patient with acquired esotropia underwent apparently successful strabismus surgery. Subsequent recurrence of esotropia, associated with square-wave jerks and downbeat nystagmus led to further investigation. Although standard CT scan was normal, rescanning after instillation of metrizamide demonstrated a Chiari I malformation. Posterior fossa decompression alleviated the esotropia. Acquired esotropia has not been recognized as a manifestation of Chiari I malformation. Our case illustrates that a high degree of suspicion is required to make the diagnosis of Chiari I malformation. Specialized techniques, such as metrizamide cisternography, or magnetic resonance imaging may be necessary if routine diagnostic measures are unrevealing.

A syndrome of congenital retinal dystrophy and saccade palsy--a subset of Leber's amaurosis

Three children who presented in infancy with a severe visual defect and absent or barely recordable electroretinograms, with relatively well preserved visually evoked cortical potentials, were subsequently found to have vertical and horizontal saccade palsies with head thrusts but relatively good visual acuity. These children, who were clearly different from other infants with congenital retinal dystrophy, were also developmentally delayed and had systemic motor and speech defects, but their visual prognosis was relatively good. The recognition of their saccade palsy was delayed because their poor visual attention in infancy was ascribed purely to the tapetoretinal degeneration. We consider these patients represent a clear subset of those patients who are diagnosed as having congenital retinal dystrophy or Leber's amaurosis.

Genetics in pediatric ophthalmology

Genetic factors are becoming increasingly important causes of both congenital and acquired eye disease in the pediatric age group. Referral to an ophthalmologist is important both for global genetic disorders potentially affecting the eye and for eye disorders that may be diagnostic for genetic disease.

Familial bilateral macular colobomata

A mother and daugher had a life-long history of poor vision and photophobia, bilateral macular colobomata, and retinal pigment epithelial abnormalities; psychoelectrophysiological testing indicated extensive loss of cone or cone-rod function. These cases suggest this is a genetically determined condition unrelated to infection.