Loss-of-function variants in UBAP1L cause autosomal recessive retinal degeneration.

PURPOSE: Inherited retinal diseases (IRDs) are a group of monogenic conditions that can lead to progressive blindness. Their missing heritability is still considerable, due in part to the presence of disease genes that await molecular identification. The purpose of this work was to identify novel genetic associations with IRDs. METHODS: Patients underwent a comprehensive ophthalmological evaluation using standard-of-care tests, such as detailed retinal imaging (macular optical coherence tomography and short-wavelength fundus autofluorescence) and electrophysiological testing. Exome and genome sequencing, as well as computer-assisted data analysis were used for genotyping and detection of DNA variants. A minigene-driven splicing assay was performed to validate the deleterious effects of 1 of such variants. RESULTS: We identified 8 unrelated families from Hungary, the United States, Israel, and The Netherlands with members presenting with a form of autosomal recessive and nonsyndromic retinal degeneration, predominantly described as rod-cone dystrophy but also including cases of cone/cone-rod dystrophy. Age of disease onset was very variable, with some patients experiencing first symptoms during their fourth decade of life or later. Myopia greater than 5 diopters was present in 5 of 7 cases with available refractive data, and retinal detachment was reported in 2 cases. All ascertained patients carried biallelic loss-of-function variants in UBAP1L (HGNC: 40028), a gene with unknown function and with homologies to UBAP1, encoding a protein involved in ubiquitin metabolism. One of these pathogenic variants, the intronic NM_001163692.2:c.910-7G>A substitution, was identified in 5 unrelated families. Minigene-driven splicing assays in HEK293T cells confirmed that this DNA change is responsible for the creation of a new acceptor splice site, resulting in aberrant splicing. CONCLUSION: We identified UBAP1L as a novel IRD gene. Although its function is currently unknown, UBAP1L is almost exclusively expressed in photoreceptors and the retinal pigment epithelium, hence possibly explaining the link between pathogenic variants in this gene and an ocular phenotype.

The 100 most cited papers on amblyopia: a bibliographic perspective.

AIM: To analyze the top 100 most cited papers related to amblyopia. METHODS: A bibliographic search in the Institute for Scientific Information Web of Knowledge across 55 years was performed. RESULTS: Eighty-nine of the 100 papers were published in first-quartile journals. Half (50) of the senior authors were from the USA. Most papers dealt with clinical science (72) and included original research (84). Forty-two of the articles related to all three types of amblyopia (refractive, strabismic and deprivation). Thirty-four related to both strabismic and refractive amblyopia. Around two-thirds of the papers dealt with treatment (34) and pathophysiology (30). Almost a quarter (23%) of the papers were multicenter studies. Nearly half (48) of the papers were published between 2000 and 2010. The Pediatric Eye Disease Investigator Group (PEDIG) published the highest number of studies (11), which dealt more with treatment (p = 0.01) and had higher average number of citations per years (p = 0.05). A larger number of articles on the treatment of amblyopia are newer (p = 0.01). There was no correlation between the time of their publication and the number of citations (p = 0.68, r = 0.042). CONCLUSIONS: Half of the papers were published between 2000 and 2010 and were spearheaded by PEDIG. Most papers dealt with treatment and pathophysiology. This study provides an important historical perspective, emphasizing the need for additional research to better understand this preventable and curable childhood vision impairment.

A large population study reveals a novel association between congenital color vision deficiency and environmental factors.

PURPOSE: To assess the associations between the prevalence of congenital color vision deficiency (CVD) and genetics and environment, represented by place of origin (ethnic background) and place of birth, respectively. METHODS: This is a retrospective study of the computerized database of the northern recruitment center of Israel of 53,895 consecutive male Jewish conscripts 16-19 years old, who completed the medical profiling process between 1988 and 2011. CVD was diagnosed using the 24-pseudo-isochromatic plate Ishihara test. Associations of CVD prevalence with sociodemographic variables, anthropometric indices, refractive errors, and mainly place of origin and place of birth were tested by both univariate analysis and multivariate regression models. RESULTS: Elevated BMI (obesity) and blood pressure (hypertension), as well as myopia, were all positively associated with congenital CVD. The composition of the study population provides a unique opportunity to investigate the relationship between ethnicity and environment. The prevalence of CVD significantly differs among subpopulations of different ethnic background as well as among those who were born in different geographical locations. Additionally, differences in the prevalence of CVD (1.2-1.6%) were observed among conscripts from the same origin, who were born in Israel, compared to those who were born elsewhere. Both place of origin (p < 0.01) and place of birth (p < 0.05) were associated with the prevalence of CVD in a multivariable regression model. CONCLUSION: This study affirms previously established associations of CVD with certain variables and reveals a possible novel association of CVD with environmental factors.

PRCD is concentrated at the base of photoreceptor outer segments and is involved in outer segment disc formation.

Mutations of the photoreceptor disc component (PRCD) gene are associated with rod-cone degeneration in both dogs and humans. Prcd is expressed in the mouse eye as early as embryonic day 14. In the adult mouse retina, PRCD is expressed in the outer segments of both rod and cone photoreceptors. Immunoelectron microscopy revealed that PRCD is located at the outer segment rim and that it is highly concentrated at the base of the outer segment. Prcd-knockout mice present with progressive retinal degeneration, starting at 20 weeks of age and onwards. This process is reflected by a significant and progressive reduction of both scotopic and photopic electroretinographic responses and by thinning of the retina, and specifically of the outer nuclear layer, indicating photoreceptor loss. Electron microscopy revealed severe damage to photoreceptor outer segments, which is associated with immigration of microglia cells to the Prcd-knockout retina and accumulation of vesicles in the inter-photoreceptor space. Phagocytosis of photoreceptor outer segment discs by the retinal pigmented epithelium is severely reduced. Our data show that Prcd-knockout mice serve as a good model for retinal degeneration caused by PRCD mutations in humans. Our findings in these mice support the involvement of PRCD in outer segment disc formation of both rod and cone photoreceptors. Furthermore, they suggest a feedback mechanism which coordinates the rate of photoreceptor outer segment disc formation, shedding and phagocytosis. This study has important implications for understanding the function of PRCD in the retina, as well as for future development of treatment modalities for PRCD deficiency in humans.

Verifying complaints of difficulties in night vision using electroretinography and dark adaptation tests.

PURPOSE: To determine the electroretinographical and psychophysical parameters that can help to verify patients' complaints of reduced night vision. METHODS: We tested 275 consecutive patients with normal appearing fundi, complaining of visual difficulties at night, using flash electroretinography (ERG) and dark adaptation (DA) test. Two ERG parameters were used to assess a scotopic retinal function: the amplitude of the response to dim blue flash (the rod response) and the b-wave ratio (measured/expected). Dark adaptation was measured with green- and red-light stimuli after exposure to a bright, bleaching light. The psychophysical parameter of night vision was defined as the threshold for detection of the blue-green stimulus that was measured after 40-45 min in complete darkness. RESULTS: Fifty-five patients were excluded from the analysis because of a discrepancy between the two ERG parameters in assessment of scotopic retinal function. The remaining 220 patients were divided into 4 groups: (1) normal ERG and normal DA, (2) subnormal ERG and subnormal DA, (3) normal ERG and subnormal DA and (4) subnormal ERG and normal DA. The ERG and DA tests supported the complaint of visual difficulties at night in 67 patients (group 2), while 34 patients were characterized as having normal scotopic visual function (group 1). The other 119 patients (groups 3 and 4) presented a diagnostic dilemma because one test (ERG or dark adaptation) showed normal scotopic function, while the other indicated subnormal scotopic function. CONCLUSION: Our findings indicate that ERG is an essential, but not sufficient test for verifying patient's complaint on visual difficulties in the dark. We suggest using both electroretinography and psychophysical dark adaptation to test patients complaining of reduced night vision.

Hydration of small leaking corneal perforations with cefuroxime.

PURPOSE: To describe a new technique for sealing small corneal perforations after penetrating trauma. METHODS: Corneal perforations in six eyes were sealed using a stromal cefuroxime hydration technique. This technique is identical to the current method used to seal leaking incisions upon completion of cataract surgery except for the use of cefuroxime instead of balanced salt solution. Additionally, cefuroxime was intentionally injected into the anterior chamber. A therapeutic contact lens was used after the hydration. Comparison was made in eight eyes with small traumatic corneal perforation that was sealed using therapeutic contact lenses without hydration. RESULTS: This novel technique was applied in six cases, with leakage stopping immediately following hydration in each of these eyes. In cases presenting with a shallow or flat anterior chamber, this maneuver produced immediate reformation of the chamber. Of note, the corneal scars after hydration were minimal with little effect on visual acuity. When compared to eyes with small corneal perforations which were sealed with therapeutic contact lenses without hydration, all cases that were hydrated with cefuroxime were sealed immediately, as opposed to cases treated without hydration. Furthermore, the eyes that underwent hydration with cefuroxime had a worse average visual acuity on admission, a better average visual acuity 1 month post-trauma, and a shorter average length of hospitalization. CONCLUSIONS: This new technique offers five major advantages: (1) Immediate sealing of the corneal perforation is achieved. (2) Definitive treatment can be achieved at the slit lamp. (3) Since neither stitches nor glue is applied, healing is achieved with minimal scarring and discomfort. (4) Little equipment is required. (5) Injection of cefuroxime into the anterior chamber provides prophylaxis against infection.

Publication outcome of abstracts submitted to the American Academy of Ophthalmology meeting.

OBJECTIVE: Abstracts submitted to meetings are subject to less rigorous peer review than full-text manuscripts. This study aimed to explore the publication outcome of abstracts presented at the American Academy of Ophthalmology (AAO) annual meeting. METHODS: Abstracts presented at the 2008 AAO meeting were analyzed. Each presented abstract was sought via PubMed to identify if it had been published as a full-text manuscript. The publication outcome, journal impact factor (IF), and time to publication were recorded. RESULTS: A total of 690 abstracts were reviewed, of which 39.1% were subsequently published. They were published in journals with a median IF of 2.9 (range 0-7.2) and a median publication time of 426 days (range 0-2,133 days). A quarter were published in the journal Ophthalmology, with a shorter time to publication (median 282 vs. 534 days, p=0.003). Oral presentations were more likely to be published than poster presentations (57.8% vs. 35.9%, p<0.001) and in journals with higher IFs (3.2 vs. 2.8, p=0.02). Abstracts describing rare diseases had higher publication rates (49.4% vs. 38.0%, p=0.04) and were published in higher IF journals (3.7 vs. 2.9, p=0.03), within a shorter period of time (358 vs. 428 days, p=0.03). In multivariate analysis, affiliation with an institute located in the United States (p=0.002), abstracts describing rare diseases (p=0.03), and funded studies (p=0.03) were associated with publication in higher IF journals. CONCLUSIONS: Almost 40% of abstracts were published. Factors that correlated with publication in journals with higher IF were a focus on rare diseases, affiliation with a US institute, and funding.

A SEMA3E mutant resistant to cleavage by furins (UNCL-SEMA3E) inhibits choroidal neovascularization.

Abnormal subretinal choroidal neovascularization (CNV) is a major cause of blindness in exudative age-related macular degeneration (AMD). Current anti-angiogenic treatments by VEGF sequestering agents have been successful, but a significant proportion of patients do not respond well to these treatments, and the response of others diminishes over time, suggesting that additional anti-angiogenic agents that function by separate mechanisms may be of use to such patients. We have previously found that a point mutated form of semaphorin-3E resistant to cleavage by furin like pro-protein convertases (UNCL-Sema3E) displays potent anti-angiogenic properties. We therefore determined if UNCL-Sema3E has potential as an inhibitor of CNV formation. We chose to study UNCL-Sema3E rather than wild type sema3E because unlike full length sema3E, the major p61-Sema3E peptide that is produced by cleavage of sema3E with furin like pro-protein convertases activates signal transduction mediated by the ErbB2 receptor and can promote tumor metastasis in addition to its anti-angiogenic activity. UNCL-Sema3E inhibited efficiently vascular endothelial growth factor-A (VEGF), platelet derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) signaling in human umbilical vein derived endothelial cells (HUVEC) and to a lesser extent hepatocyte growth factor (HGF) signal transduction. CNV that was induced in the eyes of C57 black mice by laser photocoagulation was inhibited by 65% (P < 0.01) following a single bolus intra-vitreal injection of 5 µg UNCL-Sema3E. This inhibitory effect was similar to the inhibition produced by a single bolus intra-vitreal injection of 5 µg aflibercept. A similar inhibition of CNV was observed following the injection of UNCL-Sema3E into the eyes of Long-Evans rats. However, a higher dose of UNCL-Sema3E (125 µg), partially due to the larger volume of the vitreous cavity of rats, was required to achieve maximal inhibition of CNV. Injection of UNCL-Sema3E into eyes of healthy mice did not have any adverse effect on retinal function as assessed by optic kinetic reflex (OKR) or by electroretinogram (ERG) assays nor did UNCL-Sema3E injection affect the structure of the retina as determined using histology. To conclude, our results suggest that UNCL-Sema3E may be useful for the treatment of exudative AMD, which does not respond well to conventional anti-VEGF therapy.

Screening for Myopia-Related Retinal Changes Among Teenagers.

BACKGROUND AND OBJECTIVE: To evaluate the relationship between spherical equivalent (SE) refractive error and myopia-related peripheral retinal changes (MPRCs) and to find the optimal cutoff for screening myopic teenagers. PATIENTS AND METHODS: The study included 2,286 myopic subjects who had a dilated fundus examination between 1998 and 2011 and SE of -4.0 diopters (D) or higher in both eyes. RESULTS: Ninety-five subjects (4.16%) had MPRCs. Two subjects (0.09%) had moderate-to-severe MPRCs. A significant correlation (P < .0001) between SE and MPRC was found. The highest sum of sensitivity (72.63%) and specificity (73.44%) was achieved when a SE of -6.25 D in the more myopic eye was utilized as the cutoff. CONCLUSIONS: SE and MPRCs are highly associated. The optimal cutoff to detect MPRC in teenagers is -6.25 D. However, using a SE of -4.0 D as the cutoff may be the practical choice for screening due to the noninvasiveness nature and low cost of the examination. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e311-e319.].

Carrier frequency analysis of mutations causing autosomal-recessive-inherited retinal diseases in the Israeli population.

Inherited retinal diseases (IRDs) are heterogeneous phenotypes caused by variants in a large number of genes. Disease prevalence and the frequency of carriers in the general population have been estimated in only a few studies, but are largely unknown. To this end, we developed two parallel methods to calculate carrier frequency for mutations causing autosomal-recessive (AR) IRDs in the Israeli population. We created an SQL database containing information on 178 genes from gnomAD (including genotyping of 5706 Ashkenazi Jewish (AJ) individuals) and our cohort of >2000 families with IRDs. Carrier frequency for IRD variants and genes was calculated based on allele frequency values and the Hardy-Weinberg (HW) equation. We identified 399 IRD-causing variants in 111 genes in Israeli patients and AJ controls. For the AJ subpopulation, gnomAD and HW-based regression analysis showed high correlation, therefore allowing one to use HW-based data as a reliable estimate of carrier frequency. Overall, carrier frequency per subpopulation ranges from 1/2.2 to 1/9.6 individuals, with the highest value obtained for the Arab-Muslim subpopulation in Jerusalem reaching an extremely high carrier rate of 44.7%. Carrier frequency per gene ranges from 1/31 to 1/11994 individuals. We estimate the total carrier frequency for AR-IRD mutations in the Israeli population as over 30%, a relatively high carrier frequency with marked variability among subpopulations. Therefore, these data are highly important for more reliable genetic counseling and genetic screening. Our method can be adapted to study other populations, either based on allele frequency data or cohort of patients.

The role of computed tomography in the immediate workup of open globe injury.

PURPOSE: Immediate primary closure is indicated in cases of traumatic open globe injury. Orbital computed tomography (CT) is performed prior to primary closure in order to rule out possible intraocular foreign bodies (IOFB) and/or damage to adjacent extraocular as well as intraocular structures. The aim of the present study is to evaluate the yield of orbital CT scan in immediate clinical decision-making in cases of open globe injury. METHODS: All cases of open globe injury treated in our institute during a 10-year period were reviewed. All underwent a CT scan before any surgical intervention, regardless of trauma severity. The influence of the CT scan results on decisions regarding the immediate treatment of the open globe injury was analyzed. RESULTS: A total of 125 cases of open globe injury were included in the present study. In none of these cases did the CT scan results have any influence on immediate treatment. The CT scan results did influence decisions that were made after the immediate operative stage. CONCLUSIONS: Computed tomography scan has limited value in immediate clinical decision-making in cases of open globe injury scheduled for primary closure. While not crucial prior to the initial procedure, it is of value in managing the case during the following few days as well as later on. This study suggests that a CT scan performed after the initial globe exploration and suturing procedure is a valid alternative to stalling the definite globe suturing process until a CT scan is obtained and interpreted.