Subretinal transplantation of forebrain progenitor cells in nonhuman primates: survival and intact retinal function

PURPOSE

Cell-based therapy rescues retinal structure and function in rodent models of retinal disease, but translation to clinical practice will require more information about the consequences of transplantation in an eye closely resembling the human eye. The authors explored donor cell behavior using human cortical neural progenitor cells (hNPC(ctx)) introduced into the subretinal space of normal rhesus macaques.

METHODS

hNPC(ctx) transduced with green fluorescent protein (hNPC(ctx)-GFP) were delivered bilaterally into the subretinal space of six normal adult rhesus macaques under conditions paralleling those of the human operating room. Outcome measures included clinical parameters of surgical success, multifocal electroretinogram (mfERG), and histopathologic analyses performed between 3 and 39 days after engraftment. To test the effects of GFP transduction on cell bioactivity, hNPC(ctx)-GFP from the same batch were also injected into Royal College of Surgeons (RCS) rats and compared with nonlabeled hNPC(ctx).

RESULTS

Studies using RCS rats indicated that GFP transduction did not alter the ability of the cells to rescue vision. After cells were introduced into the monkey subretinal space by a pars plana transvitreal approach, the resultant detachment was rapidly resolved, and retinal function showed little or no disturbance in mfERG recordings. Retinal structure was unaffected and no signs of inflammation or rejection were seen. Donor cells survived as a single layer in the subretinal space, and no cells migrated into the inner retina.

CONCLUSIONS

Human neural progenitor cells can be introduced into a primate eye without complication using an approach that would be suitable for extrapolation to human patients.

Polymorphisms in C2, CFB and C3 are associated with progression to advanced age related macular degeneration associated with visual loss

BACKGROUND

Age related macular degeneration (AMD) is a leading cause of blindness. AMD is a complex disorder caused by genetic and environmental factors in which single nucleotide polymorphisms (SNPs) in the genes CFH and LOC387715/HTRA1/ARMS2 have prognostic importance for progression to advanced AMD (with visual loss). CFH may also have a pharmacogenetic role by affecting treatment response to widely used nutritional supplements. This paper examines other AMD susceptibility genes to determine if these genotypes influenced disease progression and treatment response.

METHODS

Three cohorts, totalling 3137 individuals, were genotyped for SNPs in 13 genes previously published to be associated with advanced AMD (other than CFH and LOC387715/ARMS2/HTRA1). Those genes found associated were then evaluated for their involvement in disease progression. Interactions between the genes and with AREDS (Age-Related Eye Disease Study) nutritional supplements were investigated.

RESULTS

Positive independent associations were noted in SNPs in the genes C2 (p = 0.0001, odds ratio (OR) 0.35, 95% confidence interval (CI) 0.2 to 0.6), CFB (p = 0.0001, OR 0.35, 95% CI 0.2 to 0.6), C3 (p = 0.0001, OR 3.91, 95% CI 1.94 to 7.88), APOE (epsilon4, p = 0.01, OR 0.50, 95% CI 0.29 to 0.86) and VEGFA (p = 0.01, OR 2.23, 95% CI 1.06 to 4.68). C2/CFB and C3 were independently related to progression from early/intermediate to advanced AMD with OR 0.32 (95% CI 0.14 to 0.73) and 3.32 (95% CI 1.46 to 7.59), respectively. Gene-gene and pharmacogenetic interactions were not observed. No preferential associations were observed with geographic atrophy or choroidal neovascularisation.

CONCLUSION

This study provides insights into the genetic pathogenesis of AMD. Five genes have now been shown to be independently involved in progression from intermediate disease (before vision loss has occurred) to advanced disease in which blindness is frequent.

Toll-like receptor 3 and geographic atrophy in age-related macular degeneration

BACKGROUND

Age-related macular degeneration is the most common cause of irreversible visual impairment in the developed world. Advanced age-related macular degeneration consists of geographic atrophy and choroidal neovascularization. The specific genetic variants that predispose patients to geographic atrophy are largely unknown.

METHODS

We tested for an association between the functional toll-like receptor 3 gene (TLR3) variant rs3775291 (involving the substitution of phenylalanine for leucine at amino acid 412) and age-related macular degeneration in Americans of European descent. We also tested for the effect of TLR3 Leu and Phe variants on the viability of human retinal pigment epithelial cells in vitro and on apoptosis of retinal pigment epithelial cells from wild-type mice and Tlr3-knockout (Tlr3(-/-)) mice.

RESULTS

The Phe variant (encoded by the T allele at rs3775291) was associated with protection against geographic atrophy (P=0.005). This association was replicated in two independent case-control series of geographic atrophy (P=5.43x10(-4) and P=0.002). No association was found between TLR3 variants and choroidal neovascularization. A prototypic TLR3 ligand induced apoptosis in a greater fraction of human retinal pigment epithelial cells with the Leu-Leu genotype than those with the Leu-Phe genotype and in a greater fraction of wild-type mice than Tlr3(-/-) mice.

CONCLUSIONS

The TLR3 412Phe variant confers protection against geographic atrophy, probably by suppressing the death of retinal pigment epithelial cells. Since double-stranded RNA (dsRNA) can activate TLR3-mediated apoptosis, our results suggest a role of viral dsRNA in the development of geographic atrophy and point to the potential toxic effects of short-interfering-RNA therapies in the eye.

Choroideremia: analysis of the retina from a female symptomatic carrier

PURPOSE

To define the retinal pathology in a 91 year-old affected matriarch of a three-generation choroideremia family with multiple manifesting carriers.

METHODS

Tissue from three different retinal areas was processed for immunohistochemistry. The macular area was processed for transmission electron microscopy. Cryosections were studied by indirect immunofluorescence, using well-characterized antibodies to cone cytoplasm, rhodopsin and cone opsins. The affected donor eyes were compared to a postmortem matched normal eye.

RESULTS

The retina displayed areas of severe degeneration, with no photoreceptor outer segments, photoreceptor nuclear atrophy, and atrophy of the inner retina. Other retinal areas were near to normal. The RPE was severely degenerated, with thinning, pigment clumping and sub-epithelial debris deposition in all the areas examined. The choroid displayed depigmentation. Labeling with cone opsin antibodies revealed that cones were drastically affected: blue opsin was almost completely absent, while red/green opsins were distributed along the entire plasma membrane of the cell. Rhodopsin was also distributed along the entire rod plasma membrane. Ultrastructural analysis of the affected macula revealed the absence of RPE apical microvilli and basal infoldings. Instead, RPE's basal surface and choroid displayed the presence of banded fibers composed of clumps of wide-spacing collagen. Bruch's membrane was filled with vesicular structures, some smooth and others with bristle-like projections.

CONCLUSIONS

The histological data suggests that the clinical manifestation in this donor is related to degenerative changes in the retina, RPE, and choroid.

Rhesus monkeys and humans share common susceptibility genes for age-related macular disease

Age-related macular degeneration (AMD), a complex multigenic disorder and the most common cause of vision loss in the elderly, is associated with polymorphisms in the LOC387715/ARMS2 and HTRA1 genes on 10q26. Like humans, macaque monkeys possess a macula and develop age-related macular pathologies including drusen, the phenotypic hallmark of AMD. We genotyped a cohort of 137 unrelated rhesus macaques with and without macular drusen. As in humans, one variant within LOC387715/ARMS2 and one in HTRA1 were significantly associated with affected status. HTRA1 and the predicted LOC387715/ARMS2 gene were both transcribed in rhesus and human retina and retinal pigment epithelium. Among several primate species, orthologous exons for the human LOC387715/ARMS2 gene were present only in Old World monkeys and apes. In functional analyses, the disease-associated HTRA1 polymorphism resulted in a 2-fold increase in gene expression, supporting a role in pathogenesis. These results demonstrate that two genes associated with AMD in humans are also associated with macular disease in rhesus macaques and that one of these genes is specific to higher primates. This is the first evidence that humans and macaques share the same genetic susceptibility factors for a common complex disease.

Joint effects of polymorphisms in the HTRA1, LOC387715/ARMS2, and CFH genes on AMD in a Caucasian population

PURPOSE

To estimate the joint effects of single nucleotide polymorphisms (SNPs) in the genes complement factor H (CFH), HtrA serine peptidase 1 (HTRA1), and age-related maculopathy susceptibility 2 (LOC387715/ARMS2) in a Caucasian age related macular degeneration (AMD) case-control cohort.

METHODS

We genotyped three SNPs, rs1061170 (exon 9, CFH), rs11200638 (HTRA1 promoter, -512 bp), and rs10490924 (6.6 kb upstream of HTRA1 in LOC387715/ARMS2) in 333 cases with advanced AMD (choroidal neovascularization [CNV] and geographic atrophy) and 171 age-matched examined controls. Association tests were performed for individual SNPs and jointly with the CFH SNP Y402H. Analyses for interaction were also performed.

RESULTS

The linkage disequilibrium measure for two SNPs on 10q26, rs10490924 and rs11200638, is D'=0.8 and all four possible haplotypes of the two SNPs were detected in the samples. The allelic association test for rs11200638 on the promoter of HTRA1 yielded p-values less than 10(-10) for geographic atrophy, less than 10(-16) for neovascularization, and less than 10(-19) for the pooled phenotypes (with an odds ration [OR] of 3.973; 95% confidence interval [CI] 2.928, 5.390). Disease risk is conferred in a dosage-dependent fashion. Similar figures were observed for the LOC387715/ARMS2 SNP. No interaction was detected between either between the 10q26 SNPs or the CFH SNP.

CONCLUSIONS

This is the first analysis to show that the two 10q26 SNPs are not in complete linkage disequilibrium. Our studies however show that both the HTRA1 and LOC387715/ARMS2 SNP appear to contribute equally to disease risk (both geographic atrophy and choroidal neovascularization) with no evidence of interaction with CFH.

Haplotypes in the complement factor H (CFH) gene: associations with drusen and advanced age-related macular degeneration

Background

Age-related macular degeneration (AMD), the leading cause of blindness in the Western world, is a complex disease that affects people over 50 years old. The complement factor H (CFH) gene has been repeatedly shown to be a major factor in determining susceptibility to the advanced form of the condition. We aimed to better understand the functional role of this gene in the AMD disease process and assess whether it is associated with earlier forms of the disease.

Methodology/Principal Findings

We genotyped SNPs at the CFH gene locus in three independent populations with AMD: (a) extended families where at least 3 family members had AMD; (b) sporadic cases of advanced AMD and (c) cases from the Age-Related Eye Disease Study (AREDS). We investigated polymorphisms and haplotypes in and around the CFH gene to assess their role in AMD. CFH is associated with early/intermediate and advanced AMD in both familial and sporadic cases. In our populations, the CFH SNP, rs2274700, is most strongly associated with AMD and when incorporated into a haplotype with the Y402H SNP and rs1061147, the strongest association is observed (p<10⁻⁹).

Conclusions/Significance

Our results, reproduced in three populations that represent the spectrum of AMD cases, provide evidence that the CFH gene is associated with drusen as well as with advanced AMD. We also identified novel susceptibility and protective haplotypes in the AMD populations.

Association of CFH Y402H and LOC387715 A69S with progression of age-related macular degeneration

CONTEXT

Studies have reported that single-nucleotide polymorphisms in the genes CFH and LOC387715 are associated with age-related macular degeneration (AMD).

OBJECTIVE

To assess whether these genetic variants have prognostic importance for progression to advanced AMD and related visual loss.

DESIGN, SETTING, AND PARTICIPANTS

Prospective analysis of 1466 white participants in the Age-Related Eye Disease Study (AREDS), a US multicenter clinical trial conducted from 1990 to 2001 with a mean follow-up time of 6.3 years. Age-related macular degeneration status was determined by grading of fundus photographs. Progression (n = 281) was defined as newly diagnosed advanced AMD (geographic atrophy, exudative disease, or AMD causing visual loss) in one or both eyes during the course of the study. Genotypic analysis was conducted in 2006.

MAIN OUTCOME MEASURE

Incidence rates of dry and neovascular advanced AMD.

RESULTS

The CFH Y402H and LOC387115 A69S polymorphisms were each independently related to progression from early or intermediate stages to advanced stages of AMD, controlling for demographic factors, smoking, body mass index, and AREDS vitamin-mineral treatment assignment, with odds ratios (ORs) of 2.6 (95% confidence interval [CI], 1.7-3.9) for CFH and 4.1 (95% CI, 2.7-6.3) for LOC387715 for the homozygous risk genotypes (P<.001 for trend for each additional risk allele for both genes). The effect of LOC387715 was stronger for progression to neovascular disease (OR, 6.1; 95% CI, 3.3-11.2) compared with geographic atrophy (OR, 3.0; 95% CI, 1.4-6.5) relative to no progression for the homozygous risk state. The presence of all adverse factors (both risk genotypes, smoking, and body mass index > or =25) increased risk 19-fold. Smoking and high body mass index increased odds of progression within each risk genotype. Genetic plus nongenetic risk scores provided an area under the receiver operating characteristic curve of up to 0.78.

CONCLUSIONS

Common polymorphisms in the genes CFH and LOC387715 are independently related to AMD progression after adjustment for other known AMD risk factors. Presence of these polymorphisms plus smoking [corrected] and body mass index of 25 or higher, controlling for AREDS vitamin-mineral treatment, identifies [corrected] patients who are highly susceptible to developing advanced states [corrected] of this visually disabling disease.

INTRAVITREAL BEVACIZUMAB (AVASTIN) TREATMENT OF NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

To report the change in visual acuity and central retinal thickness by optical coherence tomography (OCT) after intravitreal injections of bevacizumab for the treatment of neovascular age-related macular degeneration (AMD).

METHODS

A retrospective case series in a university-based practice evaluated patients with subfoveal choroidal neovascularization (CNV) due to AMD. Patients received intravitreal injections (1.25 mg) of bevacizumab and were monitored monthly with determination of best-corrected ETDRS visual acuity and OCT for persistence of retinal thickening. Eyes were retreated on an "as needed" basis, defined by presence of intraretinal or subretinal fluid. Patients were monitored every 2 months to 3 months for persistence of angiographic leakage.

RESULTS

Seventy-nine eyes of 74 consecutive patients received the initial injection of bevacizumab between August 1, 2005, and January 30, 2006. Sixty-eight eyes (86%) of 64 patients had at least 3 months of follow-up. Mean central retinal thickness +/- SD decreased from 304 +/- 83 microm at baseline to 237 +/- 105 microm at 3 months (P = 0.00002). Mean ETDRS visual acuity gained 4 letters from 20/100 at baseline to 20/80-1 at 3 months (P = 0.040). Twenty eyes (25%) appeared to have a sustained response to a single injection and did not require further injections through 3 months. Two patients had a potentially drug-related adverse event (ischemic stroke and myocardial infarction). No serious injection-related adverse events occurred.

CONCLUSIONS

Intravitreal bevacizumab injection affects a rapid decrease in retinal thickness to normal or near-normal levels and improvement in visual acuity in eyes with CNV due to AMD. The sustainability of changes in retinal thickness and visual acuity in response to bevacizumab treatment warrant further investigation and long-term follow-up.

The LOC387715 Gene, Smoking, Body Mass Index, Environmental Associations with Advanced Age-Related Macular Degeneration

BACKGROUND AND AIMS

Age-related macular degeneration (AMD) is the leading cause of blindness in the Western World. It is now evident that both genetic and environmental factors contribute to disease susceptibility. We tested the hypotheses that (a) a common coding SNP in the LOC387715 gene is associated with advanced AMD (geographic atrophy or choroidal neovascularization), and (b) that modifiable environmental exposures alter AMD susceptibility associated with this SNP.

METHODS

A case-control association analysis was performed on participants (530 advanced AMD cases and 280 controls) ascertained as part of the multi-center Age-Related Eye Disease Study. AMD status was determined by the reading center from fundus photographs using the AREDS AMD grading categorization. Environmental risk factor exposure data was collected from participants whose DNA was also genotyped for the LOC387715 gene SNP rs10490924. Multivariate logistic regression analyses were performed.

RESULTS AND CONCLUSIONS

The number of risk alleles at the LOC387715 SNP was associated with advanced AMD, with odds ratios (OR) = 3.0 (95% confidence interval (CI) 2.1-4.3) for the GT heterozygous genotype and OR = 12.1 (5.6-26.5) for the homozygous TT risk genotype, after controlling for demographic and behavioral risk factors. The LOC387715 SNP was associated with both forms of advanced AMD. Current cigarette smoking and body mass index were independently related to AMD, controlling for genotype. However, there was no statistical interaction between LOC387715 genotype and smoking with regard to advanced AMD development.

Expanded genome scan in extended families with age-related macular degeneration

PURPOSE

To investigate further the genetic contribution to age-related macular degeneration (AMD), increasing the power of a previous analysis and reproducing the original findings.

METHODS

A large cohort of families with this condition was assembled, and an expanded genome scan was performed with 556 microsatellite markers. In 2003, the results were reported of a genome-wide linkage analysis of 70 of these pedigrees. Members of 51 new families have now been ascertained and many of the original pedigrees expanded. Parametric and nonparametric linkage analyses were performed with a denser map of markers. In addition, analyses were performed with the sample stratified by age at ascertainment and by two major advanced phenotypes for the disease: neovascular AMD (choroidal neovascularization) and geographic atrophy.

RESULTS

The results corroborate the macular degeneration-susceptibility loci consistently reported by the authors and others in genome-wide scans. New loci were identified, including the finding of a two-point HLOD of 3.70 at 6q25.2.

CONCLUSIONS

The results suggest that the use of families enriched in predisposition to AMD has legitimacy. Genetic analyses of a genome-wide scan performed on our large cohort of families add further confirmatory evidence that susceptibility loci lie on 1q, 3p, 9q, and 10q. Furthermore, new loci have been identified, including a locus on 6q.

Photodynamic therapy of subfoveal choroidal neovascularization secondary to reticular pattern dystrophy: three-year results of an uncontrolled, prospective case series

PURPOSE

To investigate the effects of photodynamic therapy (PDT) on subfoveal choroidal neovascularization (CNV) secondary to reticular pattern dystrophy (RPD) of the retinal pigment epithelium.

DESIGN

Open-label, prospective, interventional case series.

METHODS

Thirteen eyes diagnosed with subfoveal CNV associated with RPD were considered. Complete ophthalmic examinations were performed at baseline and thereafter at three-month intervals for three years. Primary outcome measure was the number of eyes with <15 letters loss (approximately <3 lines) at 12, 24, and 36 months, compared with baseline. Secondary outcome measures included CNV progression and number of PDT sessions.

RESULTS

Seven eyes showed a decrease in best-corrected visual acuity of at least three lines at three-year examination. Each eye received a median number of treatments of two, zero, and zero in years one, two, and three, respectively.

CONCLUSIONS

PDT does not appear to guarantee long-term vision stabilization in RPD-related subfoveal CNV, and alternative therapies should be investigated.

Genetic and phenotypic heterogeneity in pattern dystrophy

BACKGROUND

The pattern dystrophies (PD) represent a clinically heterogeneous family of inherited macular diseases frequently caused by mutations in the peripherin/RDS gene. Most previous studies have detailed the clinical findings in single families, making it difficult to derive data from which progression and visual outcome can be generalised.

METHODS

Families were ascertained and clinically evaluated including angiography and electrophysiology where appropriate.

RESULTS

In each of the six families with autosomal dominant PD, a mutation in the peripherin/RDS gene was identified, including a novel Cys250Phe variant. These data suggest that the condition is characterised by the accumulation of yellow to grey subretinal flecks, followed by pigmentary change accompanied by patches of chorioretinal atrophy. Subsequently, 50% (16/32) of individuals with PD developed poor central vision because of chorioretinal geographic atrophy or subretinal neovascularisation. The risk of these complications appears to increase with age.

CONCLUSION

PD should not necessarily be considered a benign condition. Instead, patients should be counselled that there is a significant chance of losing central vision in their later years. Some elderly patients with probands showing PD may be misdiagnosed with age related macular degeneration owing to the phenotypic similarities between these conditions in the advanced state.

Posterior polar cataract is the predominant consequence of a recurrent mutation in the PITX3 gene

BACKGROUND

The authors recently identified three large genetically unrelated families with an identical 17 base pair duplication mutation in exon 4 of the PITX3 gene. Here, they report the detailed clinical phenotype.

METHODS

Affected and unaffected individuals in the three families with autosomal dominant posterior polar cataract underwent full clinical examination and donated blood samples for DNA extraction and molecular genetic studies.

RESULTS

In all three families, an identical 17 base pair duplication mutation in PITX3 was identified which co-segregated with disease status in the family. All affected individuals had bilateral progressive posterior polar cataracts. In one family, posterior polar cataract was the only clinical abnormality but in the other two families, one of 10 affected individuals and four of 11 affected individuals also had anterior segment mesenchymal dysgenesis (ASMD).

CONCLUSION

Mutations in the PITX3 gene in humans result in posterior polar cataract and variable ASMD. The gene encodes a transcription factor which has a key role in lens and anterior segment development. The mechanism by which the mutant protein gives rise to such a regional pattern of lens opacity remains to be elucidated.

Acute zonal occult outer retinopathy: towards a set of diagnostic criteria

BACKGROUND

Individuals with acute zonal occult outer retinopathy (AZOOR) present with initially progressive scotomata and photopsia. Characteristically, the extent of the visual field defect is unexplained by fundal examination, but there is marked retinal dysfunction evident electrophysiologically. It is the authors' experience that a group of patients exhibit characteristic clinical and electrophysiological abnormalities, which serve as criteria for a working diagnosis.

METHODS

A retrospective observational case series of 28 patients were identified with the clinical diagnosis of AZOOR who shared similar abnormal electrophysiology. Details of the history and ophthalmic findings were obtained from the case notes.

RESULTS

Electrophysiology demonstrated a consistent pattern of dysfunction both at the photoreceptor/retinal pigment epithelial complex but also at inner retinal levels, essentially comprising a delayed 30 Hz flicker ERG and a reduction in the EOG light rise.

CONCLUSION

This study determines diagnostic criteria applicable to a group of patients with AZOOR, typically those with classic symptomatology. Electrophysiological testing can help avoid lengthy, costly, and potentially invasive investigations, and the unnecessary use of immunosuppressive therapy.

Molecular genetic basis of inherited cataract and associated phenotypes

Congenital cataract is a leading cause of visual disability in children. Inherited isolated (non-syndromic) cataract represents a significant proportion of cases and recently many causative genetic mutations have been identified. Inherited cataract is known to be clinically and genetically heterogeneous. Eleven clear-cut cataract phenotypes have been described. Cataract may be inherited as autosomal dominant, autosomal recessive, or X-linked recessive traits, and 12 loci and 15 specific genes associated with inherited isolated cataract have been identified to date; it is likely that more genes remain to be discovered. The identification of remaining genes will not only improve our understanding of the mechanism of cataract formation but will shed new light on the developmental biology and biochemistry of the lens. Furthermore, it is possible that some of these genes will be implicated in the more common age related cataract, which also has a genetic component to its etiology.

Genetics of childhood cataract

PURPOSE OF REVIEW

Congenital cataracts, although much less common than their age-related counterparts, account for one-tenth of cases of childhood blindness. Approximately half are inherited, either in isolation or as part of a syndrome of ocular or systemic anomalies. This article reviews recent advances made in understanding the molecular genetic basis of isolated, nonsyndromic inherited cataract.

RECENT FINDINGS

New disease-causing mutations continue to be identified and now encompass genes encoding a wide variety of different lens proteins. More detailed investigations of the functional consequences of each mutation are being reported and suggest that lens opacification results not only from precipitation and amyloid-like accumulation of proteins essential for lens transparency but also from interference with their secondary functions.

SUMMARY

Improved functional characterization of mutations causing childhood cataract will improve understanding of lens development and physiology but will also have implications for the more common age-related cataract. This too has a significant genetic component to its etiology, and genes causing monogenic forms of childhood inherited cataract represent excellent candidate genes for age-related cataract. The identification of the genes conferring increased risk of developing age-related cataract will bring closer the development of a medical treatment to delay the onset of lens opacification and need for surgery.

Genetics of age-related macular degeneration

Gene discoveries will lead to more effective them pies for AMD by identifying specific underlying disease mechanisms that might be corrected by drugs or gene therapy. For example, investigations are currently being carried out using pigment epithelium-derived factor (FEDF). The gene for this potent inhibitor of angiogenesis has been incorporated into an adenoviral vector and delivered into the eye by intravitreal injection to inhibit growth of new blood vessels in eyes with neovascular AMD. In the future, as the genetics of this complex disease are unraveled, more effective treatments and preventative measures that target specific molecular defects underlying the development of AMD can be expected.

Benign intracranial hypertension in children following renal transplantation

Benign intracranial hypertension (BIH) is a condition characterized by headache, papilledema, and a raised cerebrospinal fluid pressure with normal cranial imaging. It is uncommon in childhood. Previously, there have been reports that children with chronic impairment of renal function may be at greater risk of developing BIH. This study involved retrospective case note analysis of children undergoing renal transplantation over the last 11 years at our institution. Nine children developed BIH after renal transplantation. The prevalence of the condition in our series was 4.4%. Several etiologically relevant risk factors were identified, including medication (nitrofurantoin, minocycline) and excess weight gain. Our results suggest that BIH may be a more frequent complication of the post-operative care of pediatric renal transplant recipients than previously thought. We hope to alert pediatric nephrologists that examination of the fundus for papilledema in all renal transplant patients complaining of headache is essential. If the diagnosis of BIH is delayed, irretrievable visual loss may not be avoided.