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Purpose: To describe the natural course, phenotype, and genotype of patients with X-linked retinoschisis (XLRS)., Design: Retrospective cohort study., Participants: Three hundred forty patients with XLRS from 178 presumably unrelated families., Methods: This multicenter, retrospective cohort study reviewed medical records of patients with XLRS for medical history, symptoms, visual acuity (VA), ophthalmoscopy, full-field electroretinography, and retinal imaging (fundus photography, spectral-domain [SD] OCT, fundus autofluorescence)., Main Outcome Measures: Age at onset, age at diagnosis, severity of visual impairment, annual visual decline, and electroretinography and imaging findings., Results: Three hundred forty patients were included with a mean follow-up time of 13.2 years (range, 0.1-50.1 years). The median ages to reach mild visual impairment and low vision were 12 and 25 years, respectively. Severe visual impairment and blindness were observed predominantly in patients older than 40 years, with a predicted prevalence of 35% and 25%, respectively, at 60 years of age. The VA increased slightly during the first 2 decades of life and subsequently transitioned into an average annual decline of 0.44% (P < 0.001). No significant difference was found in decline of VA between variants that were predicted to be severe and mild (P = 0.239). The integrity of the ellipsoid zone (EZ) as well as the photoreceptor outer segment (PROS) length in the fovea on SD OCT correlated significantly with VA (Spearman's ρ = -0.759 [P < 0.001] and -0.592 [P = 0.012], respectively). Fifty-three different RS1 variants were found. The most common variants were the founder variant c.214G→A (p.(Glu72Lys)) (101 patients [38.7%]) and a deletion of exon 3 (38 patients [14.6%])., Conclusions: Large variabilities in phenotype and natural course of XLRS were seen in this study. In most patients, XLRS showed a slow deterioration starting in the second decade of life, suggesting an optimal window of opportunity for treatment within the first 3 decades of life. The integrity of EZ as well as the PROS length on SD OCT may be important in choosing optimal candidates for treatment and as potential structural end points in future therapeutic studies. No clear genotype-phenotype correlation was found., (Copyright © 2021 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To describe the phenotypic spectrum of a large cohort of albino patients, to investigate the relationship between the ocular abnormalities and the visual acuity (VA), and to define diagnostic criteria for the white population. We also estimated the prevalence of albinism in The Netherlands., Design: Retrospective cohort study., Participants: We investigated the phenotype of 522 patients with albinism from the databases of Bartiméus (452 patients), Leiden University Medical Center (44 patients), and the Academic Medical Center Amsterdam (26 patients)., Methods: We collected clinical, genetic, and electrophysiologic data of patients with albinism. We used grading schemes for iris translucency, fundus hypopigmentation, and foveal hypoplasia., Main Outcome Measures: Visual acuity, nystagmus, iris translucency, fundus pigmentation, foveal hypoplasia, and misrouting., Results: Nystagmus was absent in 7.7% (40/521), iris translucency could not be detected in 8.9% (44/492), 3.8% (19/496) had completely normal fundus pigmentation, 0.7% (3/455) had no foveal hypoplasia, and misrouting was not established in 16.1% (49/304). The VA varied from -0.1 to 1.3 logarithm of the minimum of angle of resolution (logMAR). The foveal hypoplasia grading correlated best with the VA (r = 0.69, P < 0.001), whereas iris translucency, fundus pigmentation, and misrouting did not predict the VA significantly. We estimated a prevalence of albinism in The Netherlands of at least 1:12 000., Conclusions: None of the characteristics of albinism were consistently present in our cohort. To be able to distinguish albinism from other conditions with similar ocular features, especially in northern and western European countries, we propose major and minor clinical criteria. Major criteria would be (1) foveal hypoplasia grade 2 or more, (2) misrouting, and (3) ocular hypopigmentation, either iris translucency or fundus hypopigmentation grade 2 or more. Minor criteria would be (1) nystagmus, (2) hypopigmentation of skin and hair, (3) grade 1 fundus hypopigmentation, and (4) foveal hypoplasia grade 1. We propose that 3 major criteria or 2 major and 2 minor criteria are necessary for the diagnosis. In the presence of a molecular diagnosis, 1 major criterion or 2 minor criteria will be sufficient., (Copyright © 2018 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To describe the phenotype, long-term clinical course, clinical variability, and genotype of patients with CRB1-associated retinal dystrophies., Design: Retrospective cohort study., Participants: Fifty-five patients with CRB1-associated retinal dystrophies from 16 families., Methods: A medical record review of 55 patients for age at onset, medical history, initial symptoms, best-corrected visual acuity, ophthalmoscopy, fundus photography, full-field electroretinography (ffERG), Goldmann visual fields (VFs), and spectral-domain optical coherence tomography., Main Outcome Measures: Age at onset, visual acuity survival time, visual acuity decline rate, and electroretinography and imaging findings., Results: A retinitis pigmentosa (RP) phenotype was present in 50 patients, 34 of whom were from a Dutch genetic isolate (GI), and 5 patients had a Leber congenital amaurosis phenotype. The mean follow-up time was 15.4 years (range, 0-55.5 years). For the RP patients, the median age at symptom onset was 4.0 years. In the RP group, median ages for reaching low vision, severe visual impairment, and blindness were 18, 32, and 44 years, respectively, with a visual acuity decline rate of 0.03 logarithm of the minimum angle of resolution per year. The presence of a truncating mutation did not alter the annual decline rate significantly (P = 0.75). Asymmetry in visual acuity was found in 31% of patients. The annual VF decline rate was 5% in patients from the genetic isolate, which was significantly faster than in non-GI patients (P < 0.05). Full-field electroretinography responses were extinguished in 50% of patients, were pathologically attenuated without a documented rod or cone predominance in 30% of patients, and showed a rod-cone dysfunction pattern in 20% of RP patients. Cystoid fluid collections in the macula were found in 50% of RP patients., Conclusions: Mutations in the CRB1 gene are associated with a spectrum of progressive retinal degeneration. Visual acuity survival analyses indicate that the optimal intervention window for subretinal gene therapy is within the first 2 to 3 decades of life., (Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: USH2A mutations are an important cause of retinitis pigmentosa (RP) with or without congenital sensorineural hearing impairment. We studied genotype-phenotype correlations and compared visual prognosis in Usher syndrome type IIa and nonsyndromic RP., Design: Clinic-based, longitudinal, multicenter study., Participants: Consecutive patients with Usher syndrome type IIa (n = 152) and nonsyndromic RP (n = 73) resulting from USH2A mutations from ophthalmogenetic clinics in the Netherlands and Belgium., Methods: Data on clinical characteristics, visual acuity, visual field measurements, retinal imaging, and electrophysiologic features were extracted from medical charts over a mean follow-up of 9 years. Cumulative lifetime risks of low vision and blindness were estimated using Kaplan-Meier survival analysis., Main Outcome Measures: Low vision and blindness., Results: Participant groups had similar distributions of gender (48% vs. 45% males in Usher syndrome type IIa vs. nonsydromic RP; P = 0.8), ethnicity (97% vs. 99% European; P = 0.3), and median follow-up time (6.5 years vs. 3 years; P = 0.3). Usher syndrome type IIa patients demonstrated symptoms at a younger age (median age, 15 years vs. 25 years; P < 0.001), were diagnosed earlier (median age, 26 years vs. 36.5 years; P < 0.001), and became visually impaired 13 years earlier (median age, 41 years vs. 54 years; P < 0.001) based on VF and 18 years earlier based on VA (median age, 54 years vs. 72 years; P < 0.001) than nonsyndromic RP patients. The presence of 2 truncating mutations in USH2A was associated mostly with the syndromic phenotype, whereas other combinations were present in both groups. We found novel variants in Usher syndrome type IIa (25%) and nonsyndromic RP (19%): 29 missense mutations, 10 indels, 14 nonsense mutations, 9 frameshift mutations, and 5 splice-site mutations., Conclusions: Most patients with USH2A-associated RP have severe visual impairment by age 50. However, those with Usher syndrome type IIa have an earlier decline of visual function and a higher cumulative risk of visual impairment than those without nonsyndromic RP. Complete loss of function of the USH2A protein predisposes to Usher syndrome type IIa, but remnant protein function can lead to RP with or without hearing loss., (Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the relative frequency of the genetic causes of the Schubert-Bornschein type of congenital stationary night blindness (CSNB) and to determine the genotype-phenotype correlations in CSNB1 and CSNB2., Design: Clinic-based, longitudinal, multicenter study., Participants: A total of 39 patients with CSNB1 from 29 families and 62 patients with CSNB2 from 43 families., Methods: Patients underwent full ophthalmologic and electrophysiologic examinations. On the basis of standard electroretinograms (ERGs), patients were diagnosed with CSNB1 or CSNB2. Molecular analysis was performed by direct Sanger sequencing of the entire coding regions in NYX, TRPM1, GRM6, and GPR179 in patients with CSNB1 and CACNA1F and CABP4 in patients with CSNB2., Main Outcome Measures: Data included genetic cause of CSNB, refractive error, visual acuity, nystagmus, strabismus, night blindness, photophobia, color vision, dark adaptation (DA) curve, and standard ERGs., Results: A diagnosis of CSNB1 or CSNB2 was based on standard ERGs. The photopic ERG was the most specific criterion to distinguish between CSNB1 and CSNB2 because it showed a "square-wave" appearance in CSNB1 and a decreased b-wave in CSNB2. Mutations causing CSNB1 were found in NYX (20 patients, 13 families), TRPM1 (10 patients, 9 families), GRM6 (4 patients, 3 families), and GPR179 (2 patients, 1 family). Congenital stationary night blindness 2 was primarily caused by mutations in CACNA1F (55 patients, 37 families). Only 3 patients had causative mutations in CABP4 (2 families). Patients with CSNB1 mainly had rod-related problems, and patients with CSNB2 had rod- and cone-related problems. The visual acuity on average was better in CSNB1 (0.30 logarithm of the minimum angle of resolution [logMAR]) than in CSNB2 (0.52 logMAR). All patients with CSNB1 and only 54% of the patients with CSNB2 reported night blindness. The dark-adapted threshold was on average more elevated in CSNB1 (3.0 log) than in CSNB2 (1.8 log). The 3 patients with CABP4 had a relative low visual acuity, were hyperopic, had severe nonspecific color vision defects, and had only 1.0 log elevated DA threshold., Conclusions: Congenital stationary night blindness 1, despite different causative mutations, shows 1 unique CSNB1 phenotype. Congenital stationary night blindness 2 caused by mutations in CABP4 merely shows cone-related problems and therefore appears to be distinct from CSNB2 caused by mutations in CACNA1F., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To describe the clinical and genetic characteristics of patients with autosomal recessive bestrophinopathy (ARB)., Design: Retrospective case series., Participants: Ten patients with ARB from 7 different families., Methods: All patients underwent a complete ophthalmic examination, including dilated fundus examination, fundus photography, and fluorescein angiography (FA). In all probands, fundus autofluorescence (FAF) imaging, spectral-domain optical coherence tomography (OCT), full-field electroretinography (ERG), electro-oculography (EOG), and Goldmann perimetry were performed. In selected patients, multifocal ERG was performed. Blood samples were obtained to analyze the BEST1 gene for biallelic mutations that confirmed the diagnosis of ARB., Main Outcome Measures: Age at onset; visual acuity; fundus appearance; characteristics on FA, FAF, OCT, full-field ERG, and EOG; BEST1 gene mutations; and genotype-phenotype correlation., Results: The age at onset varied widely, from 2 to 54 years. A spectrum of fundus abnormalities was observed, such as multifocal yellowish subretinal deposits, subretinal fibrous scars, and cystoid intraretinal fluid collections in the macula. All ARB patients were hyperopic, and some had shallow anterior chamber angles that predisposed them to angle-closure glaucoma. The EOG results were abnormal in all patients. The full-field ERG results were abnormal in 8 ARB patients, whereas 2 patients demonstrated normal cone and rod responses on full-field ERG. Nine ARB patients carried biallelic mutations in the BEST1 gene, and in 1 patient with a characteristic ARB phenotype, only 1 mutation could be identified. Seven different mutations were detected, including 4 novel mutations., Conclusions: Autosomal recessive bestrophinopathy is a recognizable phenotype caused by autosomal recessively inherited mutations in the BEST1 gene. A differential diagnosis with other conditions can be made on the basis of marked autofluorescence changes in combination with an absent light rise on the EOG that outweighs the full-field ERG abnormalities, which point to the BEST1-related hereditary nature of the disease. A number of currently available therapeutic options should be considered in ARB, a disease that seems to be a suitable candidate for future gene therapy., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate the clinical course, genetic etiology, and visual prognosis in patients with cone dystrophy (CD) and cone-rod dystrophy (CRD)., Design: Clinic-based, longitudinal, multicenter study., Participants: Consecutive probands with CD (N = 98), CRD (N = 83), and affected relatives (N = 41 and N = 17, respectively) from various ophthalmogenetic clinics in The Netherlands, Belgium, and the United Kingdom., Methods: Data on best-corrected Snellen visual acuity, color vision, ophthalmoscopy, fundus photography, Goldmann perimetry, and full-field standard electroretinogram (ERG) from all patients were registered from medical charts over a mean follow-up of 19 years. The ABCA4, CNGB3, KCNV2, PDE6C, and RPGR genes were analyzed by direct sequencing in autosomal recessive (AR) and X-linked (XL), respectively. Genotyping was not undertaken for autosomal-dominant cases., Main Outcome Measures: The 10-year progression of all clinical parameters and cumulative lifetime risk of low vision and legal blindness were assessed., Results: The mean age onset for CD was 16 years (standard deviation, 11), and of CRD 12 years (standard deviation, 11; P = 0.02). The pattern of inheritance was AR in 92% of CD and 90% of CRD. Ten years after diagnosis, 35% of CD and 51% of CRD had a bull's eye maculopathy; 70% of CRD showed absolute peripheral visual field defects and 37% of CD developed rod involvement on ERG. The mean age of legal blindness was 48 (standard error [SE], 3.1) years in CD, and 35 (SE, 1.1; P<0.001) years in CRD. ABCA4 mutations were found in 8 of 90 (9%) of AR-CD, and in 17 of 65 (26%) of AR-CRD. Other mutations were detected in CNGB3 (3/90; 3%), KCNV2 (4/90; 4%), and in PDE6C (1/90; 1%). The RPGR gene was mutated in the 2 XL-CD and in 4 of 5 (80%) of XL-CRD. ABCA4 mutations as well as age of onset <20 years were significantly associated with a faster progression to legal blindness (P<0.001)., Conclusions: Although CD had a slightly more favorable clinical course than CRD, both disorders progressed to legal blindness in the majority of patients. Mutations in the ABCA4 gene and early onset of disease were independent prognostic parameters for visual loss. Our data may serve as an aid in counseling patients with progressive cone disorders., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To develop a high-throughput, cost-effective diagnostic strategy for the identification of known and new mutations in 90 retinal disease genes., Design: Evidence-based study., Participants: Sixty patients with a variety of retinal disorders, including Leber's congenital amaurosis, ocular albinism, pseudoxanthoma elasticum, retinitis pigmentosa, and Stargardt's disease., Methods: We designed a custom 300-kb resequencing chip. Polymerase chain reaction (PCR) amplification, DNA fragmentation, and chip hybridization were performed according to Affymetrix recommendations. Hybridization signals were analyzed using Sequence pilot module seq-C mutation detection software (2009). This resequencing approach was validated by Sanger sequence technology., Main Outcome Measures: Disease-causing sequence changes., Results: We developed a retinal resequencing chip that covers all exons of 90 retinal disease genes. We developed and tested multiplex primer sets for 1445 amplicons representing the genes included on the chip. We validated our approach by screening 87 exons from 25 retinal disease genes containing 87 known sequence changes previously identified in our patient group using Sanger sequencing. Call rates for successfully hybridized amplicons were 98% to 100%. Of the known single nucleotide changes, 99% could be detected on the chip. As expected, deletions could not be detected reliably., Conclusions: We designed a custom resequencing chip that can detect known and new sequence changes in 90 retinal disease genes using a new high-throughput strategy with a high sensitivity and specificity for one tenth of the cost of conventional direct sequencing. The developed amplification strategy allows for the pooling of multiple patients with non-overlapping phenotypes, enabling many patients to be analyzed simultaneously in a fast and cost-effective manner., (Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To describe the disease course in patients with vitelliform macular dystrophy (VMD) with a Best1 mutation and to determine the association between Best1 genotype and visual prognosis., Design: Consecutive case series., Participants: Fifty-three patients with VMD with Best1 mutations from 27 Dutch families, aged 11 to 87 years., Methods: Best-corrected visual acuity (VA), fundus appearance, and Arden ratio on the electro-oculogram (EOG) during clinical follow-up were assessed from medical records. Mutation analysis of the Best1 gene was performed on DNA samples using denaturing high-pressure liquid chromatography and direct sequencing., Main Outcome Measures: Cumulative lifetime risk of visual decline below 0.5, 0.3, and 0.1 for the entire group and stratified for genotype., Results: Median age of onset of visual symptoms was 33 years (range: 2-78). The cumulative risk of VA below 0.5 (20/40) was 50% at 55 years and 75% at 66 years. The cumulative risk of decline less than 0.3 (20/63) was 50% by age 66 years and 75% by age 74 years. Two patients progressed to VA less than 0.1 (20/200). Fourteen different mutations were found. Most patients (96%) had missense mutations; the Thr6Pro, Ala10Val, and Tyr227Asn mutations were most common. Visual decline was significantly faster in patients with an Ala10Val mutation than either the Thr6Pro or the Tyr227Asn mutation (P=0.001)., Conclusions: Age of onset of visual symptoms varies greatly among patients with VMD. All patients show a gradual decrease in VA, and most progress to visual impairment at a relatively late age. Our data suggest a phenotype-genotype correlation, because the Ala10Val mutation has a more rapid disease progression than other common mutations., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the association between variants in the complement component 5 (C5) gene and age-related macular degeneration (AMD)., Design: Separate and combined data from 3 large AMD case-control studies and a prospective population-based study (The Rotterdam Study)., Participants: A total of 2599 AMD cases and 3458 ethnically matched controls., Methods: Fifteen single nucleotide polymorphisms (SNPs) spanning the C5 gene were initially genotyped in 375 cases and 199 controls from The Netherlands (The Amsterdam/Rotterdam-Netherlands [AMRO-NL] study population). Replication testing of selected SNPs was performed in the Rotterdam Study (NL) and study populations from Southampton, United Kingdom (UK), and New York, United States (US)., Main Outcome Measures: Early and late stages of prevalent and incident AMD, graded according to (a modification of) the international grading and classification system of AMD., Results: Significant allelic or genotypic associations between 8 C5 SNPs and AMD were found in the AMRO-NL study and this risk seemed to be independent of CFH Y402H, LOC387715 A69S, age, and gender. None of these findings could be confirmed consistently in 3 replication populations., Conclusions: Although the complement pathway, including C5, plays a crucial role in AMD, and the C5 protein is present in drusen, no consistent significant associations between C5 SNPs and AMD were found in any of these studies. The implications for genetic screening of AMD are discussed., (Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To explore the association between polymorphisms in the complement component 3 (C3) gene and age-related macular degeneration (AMD), and to investigate the modifying effect of complement factor H (CFH) Y402H, LOC387715 A69S and smoking., Design: Pooled data from the prospective, population-based Rotterdam Study (enrolment between 1990 and 1993, and 3 follow-up examinations between September 1, 1993, and December 31, 2004) and an independent case-control study from the Netherlands., Participants: The Rotterdam Study comprised a total of 6418 persons aged >or=55 years who had gradable fundus photographs. The case-control study consisted of 357 unrelated AMD patients and 173 control individuals aged >or=55 years., Methods: The variants R102G and P314L of the C3 gene, CFH Y402H and LOC387715 A69S, were genotyped in all study participants. Information on cigarette smoking was obtained by interview at baseline., Main Outcome Measures: Early and late stages of prevalent and incident AMD, graded according to the international classification and grading system for AMD., Results: We found a population frequency of 0.217 for R102G and 0.211 for P314L in the Rotterdam Study. Both alleles significantly increased the risk of early AMD and all subtypes of late AMD, and this risk seemed to be independent of CFH Y402H, LOC387715 A69S, and smoking. Detailed analysis showed that the haplotype carrying both alleles had the highest frequency difference between cases and controls (P=0.006). We estimated a total population-attributable risk of 14.6%. A meta-analysis of all currently available data yielded a pooled odds ratio (OR) of 1.61 (95% confidence interval [CI], 1.46-1.78) for the R102G allele, and an OR of 1.50 (95% CI, 1.31-1.71) for the P314L allele., Conclusions: Our study showed a significant association between variants in the C3 gene and AMD and further highlights the crucial role of the complement pathway in the etiology of AMD.