Visual acuity changes in patients with leber congenital amaurosis and mutations in CEP290

Gene Editing for CEP290-Associated Retinal Degeneration

BACKGROUND

CEP290-associated inherited retinal degeneration causes severe early-onset vision loss due to pathogenic variants in CEP290. EDIT-101 is a clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) gene-editing complex designed to treat inherited retinal degeneration caused by a specific damaging variant in intron 26 of CEP290 (IVS26 variant).

METHODS

We performed a phase 1-2, open-label, single-ascending-dose study in which persons 3 years of age or older with CEP290-associated inherited retinal degeneration caused by a homozygous or compound heterozygous IVS26 variant received a subretinal injection of EDIT-101 in the worse (study) eye. The primary outcome was safety, which included adverse events and dose-limiting toxic effects. Key secondary efficacy outcomes were the change from baseline in the best corrected visual acuity, the retinal sensitivity detected with the use of full-field stimulus testing (FST), the score on the Ora-Visual Navigation Challenge mobility test, and the vision-related quality-of-life score on the National Eye Institute Visual Function Questionnaire-25 (in adults) or the Children's Visual Function Questionnaire (in children).

RESULTS

EDIT-101 was injected in 12 adults 17 to 63 years of age (median, 37 years) at a low dose (in 2 participants), an intermediate dose (in 5), or a high dose (in 5) and in 2 children 9 and 14 years of age at the intermediate dose. At baseline, the median best corrected visual acuity in the study eye was 2.4 log10 of the minimum angle of resolution (range, 3.9 to 0.6). No serious adverse events related to the treatment or procedure and no dose-limiting toxic effects were recorded. Six participants had a meaningful improvement from baseline in cone-mediated vision as assessed with the use of FST, of whom 5 had improvement in at least one other key secondary outcome. Nine participants (64%) had a meaningful improvement from baseline in the best corrected visual acuity, the sensitivity to red light as measured with FST, or the score on the mobility test. Six participants had a meaningful improvement from baseline in the vision-related quality-of-life score.

CONCLUSIONS

The safety profile and improvements in photoreceptor function after EDIT-101 treatment in this small phase 1-2 study support further research of in vivo CRISPR-Cas9 gene editing to treat inherited retinal degenerations due to the IVS26 variant of CEP290 and other genetic causes. (Funded by Editas Medicine and others; BRILLIANCE ClinicalTrials.gov number, NCT03872479.).

Clinical, Ophthalmic and Genetic Characterization of RPGRIP1-Associated Leber Congenital Amaurosis/Early Onset Severe Retinal Dystrophy

PURPOSE

To present the clinical characteristics, retinal features, natural history, and genetics of RPGRIP1-Associated Early Onset Severe Retinal Dystrophy (EOSRD)/Leber Congenital Amaurosis (LCA).

DESIGN

Retrospective case series.

METHODS

Review of clinical notes, multi-modal retinal imaging, and molecular diagnosis of 18 patients (17 families) with EOSRD/LCA and disease-causing variants in RPGRIP1.

RESULTS

The mean age of visual symptoms onset was 0.87 ± 1 year (birth-3 years) and the mean age at baseline visit was 11.4 ± 10.2 years (1-39 years). At the baseline visit, 44% of patients were legally blind (range= 2-39 years) and there was no significant association found between age and best corrected visual acuity (BCVA) in cross sectional analysis. Retinal evaluation showed an abolished electroretinogram or a cone-rod dystrophy pattern, none or minimal pigment deposits, a hyperautofluorescent ring at the posterior pole, and a largely preserved central macular architecture, with retained outer nuclear layer and ellipsoid zone island into adulthood. Eleven variants (48%) were previously unreported, and 13 families (76%) had a double null genotype (DN). Twelve patients (67%) had follow up assessments over a 15.7 ± 9.5 year period. The rate of BCVA decline was 0.02 LogMAR (1 letter)/year.

CONCLUSIONS

RPGRIP1-EOSRD/LCA often presents at birth or early infancy, with nystagmus, decreased VA, hyperopia, and photophobia. Patients with a DN genotype may develop symptoms earlier and have worse vision. Multimodal imaging may show a hyperautofluorescent posterior pole ring, and relatively preserved central macular architecture, suggesting that the condition is a promising candidate for gene supplementation.

Phenotyping and genotyping inherited retinal diseases: Molecular genetics, clinical and imaging features, and therapeutics of macular dystrophies, cone and cone-rod dystrophies, rod-cone dystrophies, Leber congenital amaurosis, and cone dysfunction syndromes

Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population and in children. The scope of this review is to familiarise clinicians and scientists with the current landscape of molecular genetics, clinical phenotype, retinal imaging and therapeutic prospects/completed trials in IRD. Herein we present in a comprehensive and concise manner: (i) macular dystrophies (Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), PRPH2-associated pattern dystrophy, Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)), (ii) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4, KCNV2 and RPGR), (iii) predominant rod or rod-cone dystrophies (retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)), (iv) Leber congenital amaurosis/early-onset severe retinal dystrophy (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (v) cone dysfunction syndromes (achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6), X-linked cone dysfunction with myopia and dichromacy (Bornholm Eye disease; OPN1LW/OPN1MW array), oligocone trichromacy, and blue-cone monochromatism (OPN1LW/OPN1MW array)). Whilst we use the aforementioned classical phenotypic groupings, a key feature of IRD is that it is characterised by tremendous heterogeneity and variable expressivity, with several of the above genes associated with a range of phenotypes.

Peripapillary Retinal Nerve Fiber Layer Thickness as a Predictor of Visual Outcomes in Patients with Acute Nonarteritic Anterior Ischemic Optic Neuropathy

Objective

To evaluate the utility of peripapillary retinal nerve fiber layer thickness (pRNFLT) for the prediction of visual outcomes, including visual acuity (VA) and visual field (VF), in subjects with acute nonarteritic anterior ischemic optic neuropathy (NAION).

Materials and Methods

We performed a retrospective study of data relating to 60 eyes of 60 subjects with acute NAION. Of these, reliable VF values were obtained at both the initial and at 6-month follow-up visits for 30 eyes, which were included in the VF analysis. The pRNFLT was measured globally and separately in all four quadrants (superior, inferior, nasal, and temporal) using optical coherence tomography at the initial visit. Multivariate analysis and the area under the curve (AUC) were used to evaluate the utility of pRNFLT for the prediction of visual outcomes, including favorable VA (VA better than or equal to 20/25) and favorable VF (visual field index (VFI) ≥90%), at the 6-month follow-up visit.

Results

The median VA and mean VFI at the initial visit were 0.40 (interquartile range (IQR): 0.40, 0.54; logarithm of the minimum angle of resolution (logMAR)) and 73.07% ± 6.73%, respectively. The median VA and mean VFI at the 6-month follow-up visit were 0.30 (IQR: 0.00, 0.70) logMAR and 69.27% ± 28.94%, respectively. Thinner temporal-quadrant pRNFLT was associated with favorable VA (odds ratio 0.98; p = 0.042) with a cut-off value of 128 µm (AUC 0.839, 95% CI: 0.732-0.947, sensitivity 77.27%, specificity 84.21%). Thinner nasal-quadrant pRNFLT was associated with favorable VF (odds ratio 0.97; p = 0.047) with a cut-off value of 105 µm (AUC 0.780, 95% CI: 0.612-0.948, sensitivity 90.00%, specificity 70.00%).

Conclusions

The pRNFLT is clinically useful for the prediction of visual outcomes in patients with acute NAION. A temporal-quadrant pRNFLT ≤128 µm and a nasal-quadrant pRNFLT ≤105 µm predict favorable VA and VF at the 6-month follow-up visit, respectively.

Clinical and Genetic Characterization of RDH12-Retinal Dystrophy in a South American Cohort

PURPOSE

To characterize the largest cohort of individuals with retinol dehydrogenase 12 (RDH12)-retinal dystrophy to date, and the first one from South America.

DESIGN

Retrospective multicenter international study.

SUBJECTS

Seventy-eight patients (66 families) with an inherited retinal dystrophy and biallelic variants in RDH12.

METHODS

Review of clinical notes, ophthalmic images, and molecular diagnosis.

MAIN OUTCOME MEASURES

Visual function, retinal imaging, and characteristics were evaluated and correlated.

RESULTS

Thirty-seven individuals self-identified as Latino (51%) and 34 as White (47%). Sixty-nine individuals (88%) had Leber congenital amaurosis (LCA)/early-onset severe retinal dystrophy. Macular and midperipheral atrophy were seen in all patients from 3 years of age. A novel retinal finding was a hyperautofluorescent ring in 2 young children with LCA. Thirty-nine patients (50%) had subsequent visits, with mean follow-up of 6.8 ± 7.3 (range, 0-29) years. Eight variants (21%) were previously unreported, and the most frequent variant was c.295C>A, p.Leu99Ile, present in 52 alleles of 32 probands. Individuals with LCA homozygous for p.Leu99Ile (31%) had a later age of onset, a slower rate of best-corrected visual acuity decrease, the largest percentage of patients with mild visual impairment, and were predicted to reach legal blindness at an older age than the rest of the cohort.

CONCLUSIONS

By describing the largest molecularly confirmed cohort to date, improved understanding of disease progression was possible. Our detailed characterization aims to support research and the development of novel therapies that may have the potential to reduce or prevent vision loss in individuals with RDH12-associated retinal dystrophy.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures.

The Clinical Findings, Pathogenic Variants, and Gene Therapy Qualifications Found in a Leber Congenital Amaurosis Phenotypic Spectrum Patient Cohort

This retrospective study examines the clinical characteristics and underlying genetic variants that exist in a Leber congenital amaurosis (LCA) patient cohort evaluated at the inherited retinal disease (IRD) clinic at the University of Minnesota (UMN)/M Health System. Our LCA cohort consisted of 33 non-syndromic patients and one patient with Joubert syndrome. We report their relevant history, clinical findings, and genetic testing results. We monitored disease presentation utilizing ocular coherence tomography (OCT) and fundus autofluorescence (FAF). Electroretinogram testing (ERG) was performed in patients when clinically indicated. Next-generation sequencing (NGS) and genetic counseling was offered to all evaluated patients. Advanced photoreceptor loss was noted in 85.7% of the subjects. All patients who underwent FAF had findings of either a ring of macular hypo/hyper AF or peripheral hypo-AF. All patients had abnormal ERG findings. A diagnostic genetic test result was identified in 74.2% of the patients via NGS single-gene testing or panel testing. Two patients in our cohort qualified for Luxturna® and both received treatment at the time of this study. These data will help IRD specialists to understand the genetic variants and clinical presentations that characterize our patient population in the Midwest region of the United States.

Comparison of clinico-radiological profile, optical coherence tomography parameters, and outcome in MOGAD and Neuromyelitis optica spectrum disorder subtypes: A prospective observational study

Objectives

The objectives of the study were to compare the clinico-radiological profile, optical coherence tomography (OCT) parameters and outcome in Myelin Oligodendrocyte Glycoprotein-IgG-associated disorders (MOGAD) and Neuromyelitis Optica Spectrum disorder subtypes.

Materials and Methods

This prospective study involved collection of data regarding neurological assessment, neuroimaging, cerebrospinal fluid analysis, OCT parameters, treatment and outcome. Disease severity and disability were assessed using Expanded Disability Status Scale and modified Rankin scale. Patients were categorized into aquaporin-4 (AQP4+), MOGAD, and double negative (DN; both AQP4 and MOG negative).

Results

Among 31 patients included, 42% were AQP4+, 32.2% were MOGAD, and 25.7% were DN. The median age at onset was comparable (AQP4+ vs. MOGAD vs. DN = 28 years vs. 24.4 years vs. 31.5years; P = 0.31). Females predominated in AQP4+ compared to MOGAD group (76.9% vs. 30%; P = 0.02). Majority of patients (73.5%) had a relapsing course with a median of two (range = 1-9) relapses. Ninety-nine demyelinating events occurred: Transverse myelitis (TM) in 60/99 (60.6%), optic neuritis (ON) in 43/99 (43.4%), area postrema (AP) syndrome in 20/99 (20.1%), and optico-spinal syndrome in 10/99 (10.1%). ON was common in MOGAD than AQP4+ patients (58.6% vs. 32.1%; P = 0.03). Spinal cord and brain lesions on magnetic resonance imaging (MRI) were seen in 90.3% and 54.8% patients, respectively. A significantly higher proportion of AQP4+ patients showed longitudinally extensive transverse myelitis as compared to MOGAD group (69.2 % vs. 20 %; P = 0.04), specifically involving dorsal cord (92.3% vs. 50%; P = 0.02). MRI brain lesions, especially involving AP, was frequent in DN than MOGAD (47.1% vs. 6.9%; P = 0.003) and AQP4+ (47.1% vs. 18.9%; P = 0.03) patients. AQP4+ group showed significant nasal RNFL thinning on OCT (P = 0.04). Although 6-month good functional outcome was better in MOGAD than DN and AQP4+ (80% vs. 71.4% vs. 41.7%) groups, they were comparable (P = 0.13).

Conclusion

Nearly three-fourth of our patients showed a relapsing course, with TM being the most common clinical presentation. AQP4+ group showed female preponderance, frequent dorsal cord longitudinally extensive transverse myelitis, less frequent ON, and greater nasal RNFL thinning compared to MOGAD group. MRI brain lesions were more common in DN patients. All three groups exhibited good response to pulse corticosteroids and showed a comparable functional outcome at 6-month follow-up.

Design and Outcomes of a Novel Multidisciplinary Ophthalmic Genetics Clinic

The Multidisciplinary Ophthalmic Genetics Clinic (MOGC) at the University of Michigan Kellogg Eye Center aims to provide medical and ophthalmic genetics care to patients with inherited ocular conditions. We have developed a clinical and referral workflow where each patient undergoes coordinated evaluation by our multidisciplinary team followed by discussions on diagnosis, prognosis, and genetic testing. Testing approaches are specific to each patient and can be targeted (single-gene, gene panel), broad (chromosomal microarray, whole-exome sequencing), or a combination. We hypothesize that this clinic model improves patient outcomes and quality of care. A retrospective chart review of patients in the MOGC from July 2020 to October 2022 revealed that the most common referral diagnoses were congenital cataracts, optic neuropathy, and microphthalmia, with 52% syndromic cases. Within this patient cohort, we saw a 76% uptake for genetic testing, among which 33% received a diagnostic test result. Our results support a tailored approach to genetic testing for specific conditions. Through case examples, we highlight the power and impact of our clinic. By integrating ophthalmic care with medical genetics and counseling, the MOGC has not only helped solve individual patient diagnostic challenges but has aided the greater population in novel genetic discoveries and research towards targeted therapeutics.

Non-syndromic Retinal Degeneration Caused by Pathogenic Variants in Joubert Syndrome Genes

Inherited retinal degenerations (IRDs) are a group of genetic disorders characterized by progressive dysfunction and loss of photoreceptors. IRDs are classified as non-syndromic or syndromic, depending on whether retinal degeneration manifests alone or in combination with other associated symptoms. Joubert syndrome (JBTS) is a genetically and clinically heterogeneous disorder affecting the central nervous system and other organs and tissues, including the neuroretina. To date, 39 genes have been associated with JBTS, a majority of which encode structural or functional components of the primary cilium, a specialized sensory organelle present in most post-mitotic cells, including photoreceptors. The use of whole exome and IRD panel next-generation sequencing in routine diagnostics of non-syndromic IRD cases led to the discovery of pathogenic variants in JBTS genes that cause photoreceptor loss without other syndromic features. Here, we recapitulate these findings, describing the JBTS gene defects leading to non-syndromic IRDs.

Correlations of Full-Field Stimulus Threshold With Functional and Anatomical Outcome Measurements in Advanced Retinitis Pigmentosa

PURPOSE

To compare full-field stimulus (FST) threshold values to conventional functional and anatomical measures commonly used in clinical practice.

DESIGN

Cross-sectional study.

METHODS

Patients with retinitis pigmentosa with nondetectable electroretinogram rod-mediated responses and light-adapted 3.0 cd·s·m2 30-Hz flicker (LA 3.0 flicker) amplitudes of 15 mV or less were included in this study. The threshold values for blue, white, and red stimuli on FST were correlated with best-corrected visual acuity, LA 3.0 flicker amplitude and implicit times, length of the ellipsoid zone (EZ) band and thickness of outer nuclear layer measurements on optical coherence tomography, and the vertical and horizontal diameters of the autofluorescent ring on autofluorescence imaging.

RESULTS

Forty-two eyes of 21 patients were included in the study. The mean FST thresholds were -22.5 ± 15.5 dB, -17.6 ± 11.5 dB, and -12.7 ± 6.0 dB for the blue, white, and red stimuli, respectively. The threshold values for the 3 FST stimuli were significantly correlated with selected functional and anatomical outcome measures. Specifically, they were strongly correlated with LA 3.0 flicker amplitude and EZ band length measured on optical coherence tomography. Using linear regression, blue and white stimulus values on FST were found to be predictive of EZ band length (R2 = 0.579 and 0.491, respectively), and the vertical (R2 = 0.694 and 0.532, respectively) and horizontal (R2 = 0.626 and 0.400, respectively) diameters of the hyperautofluorescent ring.

CONCLUSIONS

The significant correlations between FST and other clinical outcome measures highlight its potential as an adjunct outcome measure.

Preoperative Peripapillary Retinal Nerve Fiber Layer Thickness as the Prognostic Factor of Postoperative Visual Functions After Endoscopic Transsphenoidal Surgery for Pituitary Adenoma

Purpose

To evaluate the prognostic ability of preoperative peripapillary retinal nerve fiber layer thickness (pRNFLT) for predicting postoperative visual functions, including the visual field index (VFI) and visual acuity (VA), of subjects with pituitary adenoma (PA) who were treated with endoscopic transsphenoidal surgery for pituitary adenoma (ETSS-PA) exclusively.

Subjects and Methods

This 11-year retrospective study was performed at a single institution in Thailand. Sixty-six eyes of 33 subjects who had a PA compressing the anterior visual pathway and were treated with ETSS-PA alone were included. The pRNFLT was measured globally and in the four quadrants preoperatively, using optical coherence tomography. Multivariable analysis and area under the curve (AUC) were used to demonstrate the prognostic ability of preoperative pRNFLT for postoperative visual functions (> 1 month but < 6 months after ETSS-PA).

Results

The mean postoperative VFI and median postoperative VA were 79.45% ± 24.24% and 0.14 [interquartile range: 0.02, 0.40] logarithm of the minimum angle of resolution. Among the 56 eyes with a reliable postoperative VFI, thicker preoperative temporal (odds ratio, 1.18; p = 0.024) and inferior (odds ratio, 1.07; p = 0.013) pRNFLT values were associated with a postoperative VFI > 90%. The strongest association occurred with the preoperative temporal pRNFLT (AUC = 0.821, 95% CI: 0.720-0.923) with a cut-off value of 60 µm. Multivariable analysis for all 66 eyes showed that thicker preoperative inferior-quadrant pRNFLT (odds ratio, 1.05; p = 0.001) was associated with a postoperative VA of at least 20/25. The strongest performance was found with the preoperative inferior pRNFLT (AUC = 0.732, 95% CI: 0.615-0.849) with a cut-off value of 105 µm.

Conclusion

Preoperative pRNFLT offers clinical utility for predicting visual functions after ETSS-PA. Temporal pRNFLT ≥ 60 µm and inferior pRNFLT ≥105 µm predicted postoperative VFI > 90% and postoperative VA better than or equal to 20/25, respectively.

Serum Vitamin D Levels and Status in Thai Optic Neuritis Subjects: A Case-Control Study

Objective

To measure serum total vitamin D or 25-hydroxyvitamin D [25(OH)D] levels and status in immune-based optic neuritis (ON) including neuromyelitis optica spectrum disorder (NMOSD)-ON, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD)-ON, autoimmune-ON, and idiopathic-ON and compare them with age- and sex-matched healthy controls. The secondary objective was to analyze the association between serum 25(OH)D levels and ON attack severity (nadir best-corrected visual acuity; nadir BCVA).

Materials and Methods

This was a single-center, case-control study. We enrolled 59 subjects (19 NMOSD-ON, 6 MOGAD-ON, 11 autoimmune-ON, 23 idiopathic-ON) diagnosed with acute immune-based ON (any ON attacks) over 11 years. Electronic medical records were reviewed and demographic data (age at sampling, sex, aquaporin-4 immunoglobulin (AQP4-IgG); myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG); other biomarkers of autoimmune disorders), ON attack severity (nadir BCVA), and serum 25(OH)D levels in the acute phase of ON were collected. Serum 25(OH)D levels of 236 age- and sex-matched healthy controls were assessed.

Results

Mean serum 25(OH)D levels were significantly lower in each group of immune-based ON compared with healthy controls (p < 0.001 for each ON group). However, mean serum 25(OH)D levels were not significantly different between four ON groups (NMOSD-ON, 20.18±5.90 ng/mL; MOGAD-ON, 23.07±4.94 ng/mL; autoimmune-ON, 21.14±5.29 ng/mL; idiopathic-ON, 19.56 ±5.12 ng/mL; p = 0.525). All immune-based ON subjects had vitamin D insufficiency or vitamin D deficiency. The prevalences of vitamin D insufficiency and vitamin D deficiency were significantly higher than in healthy controls in each ON group (both p < 0.05 in each ON group). No associations were observed between serum 25(OH)D levels and ON attack severity (nadir BCVA).

Conclusions

Thai immune-based ON subjects had lower serum 25(OH)D levels and higher prevalence of vitamin D insufficiency and vitamin D deficiency compared with age- and sex-matched healthy controls. Serum 25(OH)D levels were not associated with ON attack severity (nadir BCVA). We highly recommend that serum 25(OH)D levels be screened in all subjects with acute immune-based ON.

Long-Term Visual Function After Fractionated Stereotactic Radiotherapy for Primary Optic Nerve Sheath Meningioma: A Retrospective Analysis of 34 Subjects

Objective

To evaluate long-term visual function after fractionated stereotactic radiotherapy (FSRT) for primary optic nerve sheath meningioma (PONSM).

Methods

This 22-year retrospective study included 34 subjects (34 affected eyes) with PONSM who were treated with FSRT exclusively. Subjects with a history of biopsy/resection were excluded. Visual function, including visual acuity (VA) and visual field mean deviation (VF MD), was evaluated at presentation (pre-radiotherapy; pre-RT) and at the final follow-up (post-radiotherapy; post-RT); treatment complications were also evaluated. Treatment success was defined as either stabilization or improvement of visual function.

Results

The median pre-RT VA and pre-RT VF MD were 0.70 logarithm of the minimum angle of resolution (logMAR; range: 0.0–2.9 logMAR) and −15.4 decibels (dB) (range: −31.4 to −3.2 dB), respectively. The median total dose of FSRT was 50 Gy (range: 45–54 Gy) and the median number of fractions was 25 (range: 25–30). The median follow-up interval was 89 months (range: 6–251 months). The median post-RT VA and post-RT VF MD were 0.48 logMAR (range: 0.0–2.9 logMAR) (p = 0.010) and −6.8 dB (range: −20.6 to −1.6 dB) (p = 0.005), respectively. Among the 34 included eyes, VA was successfully treated in 29 eyes (85.3%) and worsened in 5 eyes (14.7%). Of the 14 eyes with both VA and reliable VF MD at pre-RT and post-RT time points, VF MD was successfully treated in 13 eyes (92.8%) and worsened in one (7.2%); overall visual function was successfully treated in 13 eyes (92.8%) and worsened in 1 eye (7.2%). Complications occurred in one subject (2.9%; radiation retinopathy).

Conclusion

Approximately 90% of PONSM subjects exhibited long-term treatment success in terms of VA, VF MD, and overall visual function after FSRT. Additionally, the incidence of complications was low. Therefore, FSRT is effective and safe treatment for PONSM.

Intravitreal antisense oligonucleotide sepofarsen in Leber congenital amaurosis type 10: a phase 1b/2 trial

CEP290-associated Leber congenital amaurosis type 10 (LCA10) is a retinal disease resulting in childhood blindness. Sepofarsen is an RNA antisense oligonucleotide targeting the c.2991+1655A>G variant in the CEP290 gene to treat LCA10. In this open-label, phase 1b/2 ( NCT03140969 ), 12-month, multicenter, multiple-dose, dose-escalation trial, six adult patients and five pediatric patients received ≤4 doses of intravitreal sepofarsen into the worse-seeing eye. The primary objective was to evaluate sepofarsen safety and tolerability via the frequency and severity of ocular adverse events (AEs); secondary objectives were to evaluate pharmacokinetics and efficacy via changes in functional outcomes. Six patients received sepofarsen 160 µg/80 µg, and five patients received sepofarsen 320 µg/160 µg. Ten of 11 (90.9%) patients developed ocular AEs in the treated eye (5/6 with 160 µg/80 µg; 5/5 with 320 µg/160 µg) versus one of 11 (9.1%) in the untreated eye; most were mild in severity and dose dependent. Eight patients developed cataracts, of which six (75.0%) were categorized as serious (2/3 with 160 µg/80 µg; 4/5 with 320 µg/160 µg), as lens replacement was required. As the 160-µg/80-µg group showed a better benefit-risk profile, higher doses were discontinued or not initiated. Statistically significant improvements in visual acuity and retinal sensitivity were reported (post hoc analysis). The manageable safety profile and improvements reported in this trial support the continuation of sepofarsen development.

Prevalence of Choroidal Abnormalities and Lisch Nodules in Children Meeting Clinical and Molecular Diagnosis of Neurofibromatosis Type 1

Purpose

To determine the prevalence of choroidal abnormalities (CAs) and Lisch nodules (LNs) in children who met the clinical diagnostic criteria (CDC) alone and those with a molecularly confirmed diagnosis (MCD) of neurofibromatosis type 1 (NF1), and to ascertain any differences between the groups.

Methods

This was a cross-sectional observational study. All children who met the CDC and/or had MCD of NF1 and underwent eye examination were included. At least two CAs or LNs between the two eyes were set as a threshold to define the presence of either abnormality. Frequencies alongside 95% confidence intervals (CIs) were calculated. The relationship between patient age and the presence of LNs and/or CAs was estimated using logistic regression.

Results

The study cohort included 94 patients; CAs (64%) were more prevalent than LNs (41%) (0.22; 95% CI, 0.08–0.36; P = 0.0023). The probability of the presence of LNs was lower than that of CAs across all ages (odds ratio = 0.37; 95% CI, 0.20–0.69; P = 0.00173). CAs were exclusively found in 37% of patients and LNs in 16%; 80% had either CAs or LNs, or both. In the CDC group (n = 41), the difference in prevalence (CAs = 68%, LNs = 51%) did not attain statistical significance (0.17; 95% CI, −0.06 to 0.40; P = 0.18). In the MCD group (n = 53), the difference in prevalence (CAs = 60%, LNs = 34%) was significant (0.26; 95% CI, 0.006–0.47; P = 0.023).

Conclusions

CAs were more frequent than LNs in pediatric NF1 patients regardless of age and MCD status. Combining ophthalmological exams with near-infrared imaging will increase the diagnostic reach in pediatric NF1.

Translational Relevance

CAs detected on near-infrared imaging are objective biomarkers in NF1. They are more prevalent and detected earlier in the pediatric population compared with LNs. Hence, the presence of CAs should be routinely ascertained in children suspected with NF1.

RNA-based therapies in inherited retinal diseases

Inherited retinal diseases (IRDs) are a genetically and phenotypically heterogeneous group of genetic eye disorders. There are more than 300 disease entities, and together this group of disorders affects millions of people globally and is a frequent cause of blindness or low-vision certification. However, each type is rare or ultra-rare. Characteristically, the impaired vision in IRDs is due to retinal photoreceptor dysfunction and loss resulting from mutation in a gene that codes for a retinal protein. Historically, IRDs have been considered incurable and individuals living with these blinding conditions could be offered only supportive care. However, the treatment landscape for IRDs is beginning to evolve. Progress is being made, driven by improvements in understanding of genotype-phenotype relationships, through advances in molecular genetic testing and retinal imaging. Alongside this expanding knowledge of IRDs, the current era of precision medicine is fueling a growth in targeted therapies. This has resulted in the first treatment for an IRD being approved. Several other therapies are currently in development in the IRD space, including RNA-based therapies, gene-based therapies (such as augmentation therapy and gene editing), cell therapy, visual prosthetics, and optogenetics. RNA-based therapies are a novel approach within precision medicine that have demonstrated success, particularly in rare diseases. Three antisense oligonucleotides (AONs) are currently in development for the treatment of specific IRD subtypes. These RNA-based therapies bring several key advantages in the setting of IRDs, and the potential to bring meaningful vision benefit to individuals living with inherited blinding disorders. This review will examine the increasing breadth and relevance of RNA-based therapies in clinical medicine, explore the key features that make AONs suitable for treating genetic eye diseases, and provide an overview of the three-leading investigational AONs in clinical trials.

Comparative Natural History of Visual Function From Patients With Biallelic Variants in BBS1 and BBS10

Purpose

The purpose of this study was to compare the natural history of visual function change in cohorts of patients affected with retinal degeneration due to biallelic variants in Bardet-Biedl syndrome genes: BBS1 and BBS10.

Methods

Patients were recruited from nine academic centers from six countries (Belgium, Canada, France, New Zealand, Switzerland, and the United States). Inclusion criteria were: (1) female or male patients with a clinical diagnosis of retinal dystrophy, (2) biallelic disease-causing variants in BBS1 or BBS10, and (3) measures of visual function for at least one visit. Retrospective data collected included genotypes, age, onset of symptoms, and best corrected visual acuity (VA). When possible, data on refractive error, fundus images and autofluorescence (FAF), optical coherence tomography (OCT), Goldmann kinetic perimetry (VF), electroretinography (ERG), and the systemic phenotype were collected.

Results

Sixty-seven individuals had variants in BBS1 (n = 38; 20 female patients and 18 male patients); or BBS10 (n = 29; 14 female patients and 15 male patients). Missense variants were the most common type of variants for patients with BBS1, whereas frameshift variants were most common for BBS10. When ERGs were recordable, rod-cone dystrophy (RCD) was observed in 82% (23/28) of patients with BBS1 and 73% (8/11) of patients with BBS10; cone-rod dystrophy (CORD) was seen in 18% of patients with BBS1 only, and cone dystrophy (COD) was only seen in 3 patients with BBS10 (27%). ERGs were nondetectable earlier in patients with BBS10 than in patients with BBS1. Similarly, VA and VF declined more rapidly in patients with BBS10 compared to patients with BBS1.

Conclusions

Retinal degeneration appears earlier and is more severe in BBS10 cases as compared to those with BBS1 variants. The course of change of visual function appears to relate to genetic subtypes of BBS.

Full-field stimulus testing: Role in the clinic and as an outcome measure in clinical trials of severe childhood retinal disease

Disease mechanisms have become better understood in previously incurable forms of early-onset severe retinal dystrophy, such as Leber congenital amaurosis (LCA). This has led to novel treatments and clinical trials that have shown some success. Standard methods to measure vision were difficult if not impossible to perform in severely affected patients with low vision and nystagmus. To meet the need for visual assays, we devised a psychophysical method, which we named full-field stimulus testing (FST). From early versions based on an automated perimeter, we advanced FST to a more available light-emitting diode platform. The journey from invention to use of such a technique in our inherited retinal degeneration clinic is reviewed and many of the lessons learned over the 15 years of application of FST are explained. Although the original purpose and application of FST was to quantify visual thresholds in LCA, there are rare opportunities for FST also to be used beyond LCA to measure aspects of vision in other inherited retinal degenerations; examples are given. The main goal of the current review, however, remains to enable investigators studying and treating LCA to understand how to best use FST and how to reduce artefact and confounding complexities so the test results become more valuable to the understanding of LCA diseases and results of novel interventions.

Leber's Congenital Amaurosis: Current Concepts of Genotype-Phenotype Correlations

Leber’s congenital amaurosis (LCA), one of the most severe inherited retinal dystrophies, is typically associated with extremely early onset of visual loss, nystagmus, and amaurotic pupils, and is responsible for 20% of childhood blindness. With advances in molecular diagnostic technology, the knowledge about the genetic background of LCA has expanded widely, while disease-causing variants have been identified in 38 genes. Different pathogenetic mechanisms have been found among these varieties of genetic mutations, all of which result in the dysfunction or absence of their encoded proteins participating in the visual cycle. Hence, the clinical phenotypes also exhibit extensive heterogenicity, including the course of visual impairment, involvement of the macular area, alteration in retinal structure, and residual function of the diseased photoreceptor. By reviewing the clinical course, fundoscopic images, optical coherent tomography examination, and electroretinogram, genotype-phenotype correlations could be established for common genetic mutations in LCA, which would benefit the timing of the diagnosis and thus promote early intervention. Gene therapy is promising in the management of LCA, while several clinical trials are ongoing and preliminary success has been announced, focusing on RPE65 and other common disease-causing genes. This review provides an update on the genetics, clinical examination findings, and genotype-phenotype correlations in the most well-established causative genetic mutations of LCA.

Spectrum of Disease Severity in Nonsyndromic Patients With Mutations in the CEP290 Gene: A Multicentric Longitudinal Study

Purpose

The purpose of this study was to perform a detailed longitudinal phenotyping and genetic characterization of 32 Italian patients with a nonsyndromic retinal dystrophy and mutations in the CEP290 gene.

Methods

We reviewed the clinical history and examinations of 32 patients with a nonsyndromic retinal dystrophy due to mutations in the CEP290 gene, followed up (mean follow-up: 5.9 years) at 3 Italian centers. The clinical examinations included: best corrected visual acuity (BCVA), optical coherence tomography (OCT), and full-field electroretinogram (ERG).

Results

Patients (mean age = 19.0 ± 3.4 years) had a mean BCVA of 1.73 ± 0.20 logMAR. Longitudinal analysis of BCVA showed a nonsignificant decline. Central retinal thickness (CRT) declined significantly with age at an exponential rate of 1.0%/year (P = 0.001). At disease onset, most patients (19/32; 49.4%) had nystagmus. The absence of nystagmus was significantly associated with better BCVA and more preserved CRT (P < 0.05). ERG showed undetectable responses in most patients (64.0%), whereas reduced scotopic and photopic responses were observed in four patients (16.0%) who had no nystagmus. We identified 35 different variants, among which 12 were novel. Our genotype-phenotype correlation analysis shows a significantly worse BCVA in patients harboring a loss-of-function mutation and the deep-intronic variant c.2991+1655A>G.

Conclusions

Our study highlights a mild phenotype of the disease, characterized by absence of nystagmus, good visual acuity, considerably preserved retinal morphology, and recordable ERG, confirming the wide spectrum of CEP290-related retinal dystrophies. Finally, in our cohort, the deep intronic variant c.2991+1655A>G was associated with a more severe phenotype.

LEBER CONGENITAL AMAUROSIS DUE TO CEP290 MUTATIONS-SEVERE VISION IMPAIRMENT WITH A HIGH UNMET MEDICAL NEED: A Review

PURPOSE

Leber congenital amaurosis due to CEP290 mutations (LCA10) is an inherited retinal disease that often results in severe visual impairment or blindness in early childhood. Currently, there are no approved treatments, highlighting the considerable unmet medical need associated with LCA10. We aimed to review the clinical characteristics of LCA10, its impact on patients and society, and the investigational treatment strategies currently in development.

METHODS

Review of the current literature.

RESULTS

LCA10 is an autosomal recessive ciliopathy, for which the CEP290 intronic variant c.2991+1655A>G (p.Cys998X) is the most common mutation. Usually diagnosed in early childhood, most patients with LCA10 have severe visual impairment during their first decade of life, which significantly affects the quality of life and development. LCA10 also has a significant societal burden (direct and indirect costs). RNA editing using antisense oligonucleotides or Staphylococcus aureus CRISPR-associated protein-9 nuclease is currently under investigation for treatment of p.Cys998X LCA10. Specifically, the antisense oligonucleotide therapy QR-110 (sepofarsen) has demonstrated encouraging safety and efficacy data in a first-in-human trial; a phase 3 clinical trial is ongoing.

CONCLUSION

Interventions that can preserve or improve vision in patients with LCA10 have considerable potential to improve the patient quality of life and reduce burden of disease.

Inherited retinal diseases: Therapeutics, clinical trials and end points-A review

Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders characterised by photoreceptor degeneration or dysfunction. These disorders typically present with severe vision loss that can be progressive, with disease onset ranging from congenital to late adulthood. The advances in genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRDs, with the first approved gene therapy and the commencement of multiple clinical trials. The scope of this review is to familiarise clinicians and scientists with the current management and the prospects for novel therapies for: (1) macular dystrophies, (2) cone and cone-rod dystrophies, (3) cone dysfunction syndromes, (4) Leber congenital amaurosis, (5) rod-cone dystrophies, (6) rod dysfunction syndromes and (7) chorioretinal dystrophies. We also briefly summarise the investigated end points for the ongoing trials.

Contemporary Management of Complex and Non-Complex Rhegmatogenous Retinal Detachment Due to Giant Retinal Tears

Purpose

To investigate the clinical features and surgical outcomes of rhegmatogenous retinal detachment (RRD) associated with giant retinal tears (GRTs) at a tertiary referral center.

Patients and Methods

A retrospective, non-consecutive interventional case series of GRT-associated RRDs that underwent primary surgical repair at the University of Michigan W.K. Kellogg Eye Center between January 1, 2011 and July 1, 2020. Clinical characteristics and preoperative, perioperative, and postoperative data were collected.

Results

Forty-eight eyes of 47 patients with GRT-associated RRDs met inclusion criteria, including those that were children (under 12 years, N=4, 8.3%), associated with a history of trauma (N=20, 41.7%) or with grade C proliferative vitreoretinopathy (PVR-C) (N=7, 14.6%) at baseline. Median age was 46 years (interquartile range (IQR): 29 years, range: 4 to 72 years), median follow-up was 28 months (IQR: 43 months, range: 3-124 months), and 83.3% (N=40) of subjects were male. Primary surgical repair for GRT-associated RRDs included pars plana vitrectomy (PPV) (N=40, 83.3%), scleral buckle (SB) (N=1, 2.1%), or combined PPV/SB (N=7, 14.6%). Surgical approach commonly involved the use of perfluorocarbon liquid (N=43, 90%) and gas tamponade (N=39, 81%). Single surgery anatomic success (SSAS) was 75% (95% CI: 60%, 85%) at 3 months and 65% (95 CI: 47%, 78%) at 2 years. Final anatomic success was achieved in all 48 eyes (100%). Median visual acuity improved from 20/250 preoperatively to 20/60 at final follow-up, with 44% (N=20) of eyes achieving postoperative visual acuity of 20/40 or better.

Conclusion

In this series from a tertiary referral center, both complex and non-complex GRT-associated RRDs were most commonly managed with PPV alone, perfluorocarbon liquid, and gas tamponade with favorable final anatomic and visual outcomes comparable to other modern GRT series.

Comparison of Early- and Late-Onset NMOSD-Related Optic Neuritis in Thai Patients: Clinical Characteristics and Long-Term Visual Outcomes

Objective

To compare demographic data, clinical and radiological characteristics, treatments, and long-term visual outcomes between patients with late-onset neuromyelitis optica spectrum disorder-related optic neuritis (LO-NMOSD-ON) (age at onset ≥ 50 years) and patients with early-onset neuromyelitis optica spectrum disorder-related optic neuritis (EO-NMOSD-ON) (age at onset < 50 years).

Patients and Methods

This retrospective study included 47 patients (69 eyes) who were diagnosed with neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON) over a 12-year period. There were 14 patients (21 eyes) and 33 patients (48 eyes) in the LO-NMOSD-ON and EO-NMOSD-ON groups, respectively.

Results

LO-NMOSD-ON–affected eyes exhibited significantly worse median nadir visual acuity (VA) at optic neuritis (ON) onset, compared with EO-NMOSD-ON–affected eyes (2.7 logMAR (range 2.6–2.9 logMAR) vs 1.95 logMAR (range 0.4–2.9 logMAR); p = 0.03). Similarly, 100% of LO-NMOSD-ON–affected eyes demonstrated a nadir VA of worse than or equal to 1.0 logMAR, compared with 62.5% of EO-NMOSD-ON–affected eyes (p = 0.03). LO-NMOSD-ON–affected eyes had a worse median final VA, compared with EO-NMOSD-ON–affected eyes (1.3 logMAR (range 0–2.9 logMAR) vs 0.3 logMAR (range 0–2.9 logMAR); adjusted p = 0.037). LO-NMOSD-ON–affected eyes more frequently exhibited a final VA of worse than or equal to 1.0 logMAR, compared with EO-NMOSD-ON–affected eyes (57.1% vs 27.0%; adjusted p = 0.039). A positive correlation was observed between age at ON onset of each eye and the final VA (logMAR) (Spearman r = 0.34, p = 0.0075). The remaining parameters did not significantly differ between the two groups.

Conclusion

Patients with LO-NMOSD-ON had significantly worse nadir VA at ON onset and significantly worse final VA, relative to patients with EO-NMOSD-ON. Age at ON onset of each eye was positively correlated with final VA (logMAR). Despite the difference in common age at onset, NMOSD-ON should be included in the differential diagnosis of late-onset acute to subacute optic neuropathy, along with ischemic optic neuropathy.

Prognostic Factors for Visual Outcomes Following the First Episode of NMOSD-Related Optic Neuritis in Affected Eyes

OBJECTIVE

We aim to identify prognostic factors for visual outcomes following a first episode of neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON) in affected eyes.

MATERIALS AND METHODS

This was a single-center, retrospective study. The study included 50 individuals who were diagnosed with NMOSD-ON (63 affected eyes) in a tertiary institution over a 12-year period. Data regarding any second, or higher, episodes of NMOSD-ON in each eye were not taken into consideration. Medical records of included individuals were reviewed. Demographic data, clinical and magnetic resonance imaging characteristics, and treatment outcomes were collected. Main outcome measures of the study were prognostic factors for good visual outcome (best-corrected visual acuity (BCVA) ≥ 20/200) following an initial episode of NMOSD-ON in affected eyes.

RESULTS

Sixty-three affected eyes of 50 individuals (3 men and 47 women) were included. BCVA at nadir that was better than counting fingers (CF) (odds ratio 10.43, 95% confidence interval 1.04, 104.45, p = 0.046) and time from NMOSD-ON onset to intravenous methylprednisolone (IVMP), less than 21 days (odds ratio 10.73, 95% confidence interval 1.91, 60.01, p = 0.007), were significantly associated with good visual outcomes.

CONCLUSION

BCVA at nadir that was better than CF and treatment with IVMP within 21 days of symptom onset were important prognostic factors of good visual outcomes following a first episode of NMOSD-ON in affected eyes.

Voretigene Neparvovec and Gene Therapy for Leber's Congenital Amaurosis: Review of Evidence to Date

Gene therapy has now evolved as the upcoming modality for management of many disorders, both inheritable and non-inheritable. Knowledge of genetics pertaining to a disease has therefore become paramount for physicians across most specialities. Inheritable retinal dystrophies (IRDs) are notorious for progressive and relentless vision loss, frequently culminating in complete blindness in both eyes. Leber’s congenital amaurosis (LCA) is a typical example of an IRD that manifests very early in childhood. Research in gene therapy has led to the development and approval of voretigene neparvovec (VN) for use in patients of LCA with a deficient biallelic RPE65 gene. The procedure involves delivery of a recombinant virus vector that carries the RPE65 gene in the subretinal space. This comprehensive review reports the evidence thus far in support of gene therapy for LCA. We explore and compare the various gene targets including but not limited to RPE65, and discuss the choice of vector and method for ocular delivery. The review details the evolution of gene therapy with VN in a phased manner, concluding with the challenges that lie ahead for its translation for use in communities that differ much both genetically and economically.

CEP290 Mutation Spectrum and Delineation of the Associated Phenotype in a Large German Cohort: A Monocentric Study

PURPOSE

Gene therapy for Leber congenital amaurosis (LCA) is becoming available, and therefore it is crucial to identify eligible candidates. We report the spectrum and associated phenotype of CEP290 mutations in the largest German cohort observed by a single clinical site.

DESIGN

Prospective cohort study.

METHODS

Twenty-three patients with mutations in CEP290 were included. Genomic DNA was analyzed by Sanger sequencing or high-throughput sequencing for all retinitis pigmentosa-associated genes in patients, and segregation analysis was done in family members. Patients underwent functional and morphologic examinations, including fundus autofluorescence and spectral-domain optical coherence tomography.

RESULTS

The most frequent mutation was c.2991+1655A>G, found in 87% of patients (20/23). Thirty percent of patients (7/23) carried the mutation in an apparent homozygous state and 57% (13/23) in a likely compound heterozygous state. The most common clinical diagnosis was LCA and/or early onset severe retinal dystrophy in 82% (19/23), followed by retinitis pigmentosa in 14% (3/23) and cone-rod dystrophy (4%, 1/23). Best-corrected visual acuity was severely reduced to residual light perception and hand motion vision, with the exception of 3 patients with best-corrected visual acuity of 0.8 (Snellen). The visual field was severely decreased and electroretinogram was undetectable in most cases; however, retinal layers at the fovea appeared to be relatively well preserved. Systemic disorders were not noticed.

CONCLUSIONS

c.2991+1655A>G is by far the most important CEP290 mutation, contributing to 87% of patients with the CEP290 mutation in Germany. In our cohort, a homozygous c.2991+1655A>G genotype presented with a more severe phenotype. National studies and further detailed phenotype analysis seem to be important to assess the need for and promise of specific gene therapies.

Treatment Potential for Macular Cone Vision in Leber Congenital Amaurosis Due to CEP290 or NPHP5 Mutations: Predictions From Artificial Intelligence

Purpose

To use supervised machine learning to predict visual function from retinal structure in retinitis pigmentosa (RP) and apply these estimates to CEP290- and NPHP5-associated Leber congenital amaurosis (LCA) to determine the potential for functional improvement.

Methods

Patients with RP (n = 20) and LCA due to CEP290 (n = 12) or NPHP5 (n = 6) mutations were studied. A patient with CEP290 mutations but mild retinal degeneration was included. RP patients had cone-mediated macular function. A machine learning technique was used to associate perimetric sensitivities to local structure in RP patients. Models trained on RP data were applied to predict visual function in LCA.

Results

The RP and LCA patients had comparable retinal structure. RP patients had peak sensitivity at the fovea surrounded by decreasing sensitivity. Machine learning could successfully predict perimetry results from segmented or unsegmented optical coherence tomography (OCT) input. Application of machine learning predictions to LCA within the residual macular island of photoreceptor structure showed differences between predicted and measured sensitivities defining treatment potential. In patients with retained vision, the treatment potential was 4.6 ± 2.9 dB at the fovea but 16.4 ± 4.4 dB at the parafovea. In patients with limited or no vision, the treatment potential was 17.6 ± 9.4 dB.

Conclusions

Cone vision improvement potential in LCA due to CEP290 or NPHP5 mutations is predictable from retinal structure using a machine learning approach. This should allow individual prediction of the maximal efficacy in clinical trials and guide decisions about dosing. Similar strategies can be used in other retinal degenerations to estimate the extent and location of treatment potential.

Leber congenital amaurosis: Current genetic basis, scope for genetic testing and personalized medicine

Retinal dystrophies are one of the leading causes of pediatric congenital blindness. Leber's congenital amaurosis (LCA) encompasses one of the most severe forms of inherited retinal dystrophy responsible for early-onset childhood blindness in infancy. These are clinically characterized by nystagmus, amaurotic pupil response and markedly reduced or in most instances completely absent full-field electroretinogram. LCA exhibits immense genetic heterogeneity. With advances in next-generation genetic technologies, tremendous progress has been achieved over the last two decades in discovering genes and genetic defects leading to retinal dystrophies. Currently, 28 genes have been implicated in the pathogenesis of LCA and with initial reports of success in management with targeted gene therapy the disease has attracted a lot of research attention in the recent time. The review provides an update on genetic basis of LCA, scope for genetic testing and pharmacogenetic medicine in diagnosis and treatment of these diseases.

Splice-Modulating Oligonucleotide QR-110 Restores CEP290 mRNA and Function in Human c.2991+1655A>G LCA10 Models

Leber congenital amaurosis type 10 (LCA10) is a severe inherited retinal dystrophy associated with mutations in CEP290. The deep intronic c.2991+1655A>G mutation in CEP290 is the most common mutation in LCA10 individuals and represents an ideal target for oligonucleotide therapeutics. Here, a panel of antisense oligonucleotides was designed to correct the splicing defect associated with the mutation and screened for efficacy and safety. This identified QR-110 as the best-performing molecule. QR-110 restored wild-type CEP290 mRNA and protein expression levels in CEP290 c.2991+1655A>G homozygous and compound heterozygous LCA10 primary fibroblasts. Furthermore, in homozygous three-dimensional iPSC-derived retinal organoids, QR-110 showed a dose-dependent restoration of mRNA and protein function, as measured by percentage and length of photoreceptor cilia, without off-target effects. Localization studies in wild-type mice and rabbits showed that QR-110 readily reached all retinal layers, with an estimated half-life of 58 days. It was well tolerated following intravitreal injection in monkeys. In conclusion, the pharmacodynamic, pharmacokinetic, and safety properties make QR-110 a promising candidate for treating LCA10, and clinical development is currently ongoing.

Leber Congenital Amaurosis Associated with Mutations in CEP290, Clinical Phenotype, and Natural History in Preparation for Trials of Novel Therapies

PURPOSE

To investigate and describe in detail the demographics, functional and anatomic characteristics, and clinical course of Leber congenital amaurosis (LCA) associated with mutations in the CEP290 gene (LCA-CEP290) in a large cohort of adults and children.

DESIGN

Retrospective case series.

PARTICIPANTS

Patients with mutations in CEP290 identified at a single UK referral center.

METHODS

Review of case notes and results of retinal imaging (color fundus photography, fundus autofluorescence [FAF] imaging, OCT), electrophysiologic assessment, and molecular genetic testing.

MAIN OUTCOME MEASURES

Molecular genetic testing, clinical findings including visual acuity and retinal imaging, and electrophysiologic assessment.

RESULTS

Forty patients with LCA-CEP290 were identified. The deep intronic mutation c.2991+1655 A>G was the most common disease-causing variant (23/40 patients) identified in the compound heterozygous state in 20 patients (50%) and homozygous in 2 patients (5%). Visual acuity (VA) varied from 6/9 to no perception of light, and only 2 of 12 patients with longitudinal VA data showed deterioration in VA in their better-seeing eye over time. A normal fundus was found at diagnosis in younger patients (mean age, 1.9 years), with older patients showing white flecks (mean age, 5.9 years) or pigmentary retinopathy (mean age, 21.7 years). Eleven of 12 patients (92%) with OCT imaging had preservation of foveal architecture. Ten of 12 patients (83%) with FAF imaging had a perifoveal hyperautofluorescent ring. Having 2 nonsense CEP290 mutations was associated with worse final VA and the presence of nonocular features.

CONCLUSIONS

Detailed analysis of the clinical phenotype of LCA-CEP290 in a large cohort confirms that there is a window of opportunity in childhood for therapeutic intervention based on relative structural preservation in the central cone-rich retina in a significant proportion of patients, with the majority harboring the deep intronic variant potentially tractable to several planned gene editing approaches.

Accuracy of Next-Generation Sequencing for Molecular Diagnosis in Patients With Infantile Nystagmus Syndrome

Importance

Infantile nystagmus syndrome (INS) is a group of disorders presenting with genetic and clinical heterogeneities that have challenged the genetic and clinical diagnoses of INS. Precise molecular diagnosis in early infancy may result in more accurate genetic counseling and improved patient management.

Objective

To assess the accuracy of genomic data from next-generation sequencing (NGS) and phenotypic data to enhance the definitive diagnosis of INS.

Design, Setting, and Participants

A single-center retrospective case series was conducted in 48 unrelated, consecutive patients with INS, with or without associated ocular or systemic conditions, who underwent genetic testing between June 1, 2015, and January 31, 2017. Next-generation sequencing analysis was performed using a target panel that included 113 genes associated with INS (n = 47) or a TruSight One sequencing panel that included 4813 genes associated with known human phenotypes (n = 1). Variants were filtered and prioritized by in-depth clinical review, and finally classified according to the American College of Medical Genetics and Genomics guidelines. Patients underwent a detailed ophthalmic examination, including electroretinography and optical coherence tomography, if feasible.

Main Outcomes and Measures

Diagnostic yield of targeted NGS testing.

Results

Among the 48 patients (21 female and 27 male; mean [SD] age at genetic testing, 9.2 [10.3] years), 8 had a family history of nystagmus and 40 were simplex. All patients were of a single ethnicity (Korean). Genetic variants that were highly likely to be causative were identified in 28 of the 48 patients, corresponding to a molecular diagnostic yield of 58.3% (95% CI, 44.4%-72.2%). FRMD7, GPR143, and PAX6 mutations appeared to be the major genetic causes of familial INS. A total of 10 patients (21%) were reclassified to a different diagnosis based on results of NGS testing, enabling accurate clinical management.

Conclusions and Relevance

These findings suggest that NGS is an accurate diagnostic tool to differentiate causes of INS because diagnostic tests, such as electroretinography and optical coherence tomography, are not easily applicable in young infants. Accurate application of NGS using a standardized, stepwise, team-based approach in early childhood not only facilitated early molecular diagnosis but also led to improved personalized management in patients with INS.

Leber congenital amaurosis/early-onset severe retinal dystrophy: clinical features, molecular genetics and therapeutic interventions

Leber congenital amaurosis (LCA) and early-onset severe retinal dystrophy (EOSRD) are both genetically and phenotypically heterogeneous, and characterised clinically by severe congenital/early infancy visual loss, nystagmus, amaurotic pupils and markedly reduced/absent full-field electroretinograms. The vast genetic heterogeneity of inherited retinal disease has been established over the last 10 - 20 years, with disease-causing variants identified in 25 genes to date associated with LCA/EOSRD, accounting for 70–80% of cases, with thereby more genes yet to be identified. There is now far greater understanding of the structural and functional associations seen in the various LCA/EOSRD genotypes. Subsequent development/characterisation of LCA/EOSRD animal models has shed light on the underlying pathogenesis and allowed the demonstration of successful rescue with gene replacement therapy and pharmacological intervention in multiple models. These advancements have culminated in more than 12 completed, ongoing and anticipated phase I/II and phase III gene therapy and pharmacological human clinical trials. This review describes the clinical and genetic characteristics of LCA/EOSRD and the differential diagnoses to be considered. We discuss in further detail the diagnostic clinical features, pathophysiology, animal models and human treatment studies and trials, in the more common genetic subtypes and/or those closest to intervention.

Improving the management of Inherited Retinal Dystrophies by targeted sequencing of a population-specific gene panel

Next-generation sequencing (NGS) has overcome important limitations to the molecular diagnosis of Inherited Retinal Dystrophies (IRD) such as the high clinical and genetic heterogeneity and the overlapping phenotypes. The purpose of this study was the identification of the genetic defect in 32 Spanish families with different forms of IRD. With that aim, we implemented a custom NGS panel comprising 64 IRD-associated genes in our population, and three disease-associated intronic regions. A total of 37 pathogenic mutations (14 novels) were found in 73% of IRD patients ranging from 50% for autosomal dominant cases, 75% for syndromic cases, 83% for autosomal recessive cases, and 100% for X-linked cases. Additionally, unexpected phenotype-genotype correlations were found in 6 probands, which led to the refinement of their clinical diagnoses. Furthermore, intra- and interfamilial phenotypic variability was observed in two cases. Moreover, two cases unsuccessfully analysed by exome sequencing were resolved by applying this panel. Our results demonstrate that this hypothesis-free approach based on frequently mutated, population-specific loci is highly cost-efficient for the routine diagnosis of this heterogeneous condition and allows the unbiased analysis of a miscellaneous cohort. The molecular information found here has aid clinical diagnosis and has improved genetic counselling and patient management.

Full-Field Pupillary Light Responses, Luminance Thresholds, and Light Discomfort Thresholds in CEP290 Leber Congenital Amaurosis Patients

PURPOSE

To investigate visual function in patients with CEP290 Leber congenital amaurosis (LCA-CEP290), using three full-field tests that can be performed by patients with poor fixation.

METHODS

Six patients (age range, 9-39 years) with LCA-CEP290 participated in the study. Stimuli for all three tests (full-field stimulus test [FST], pupillometry, and light discomfort threshold [LDT] testing) were generated by the Diagnosys ColorDome ganzfeld, by using achromatic stimuli as well as long- and short-wavelength stimuli to target rod and cone photoreceptors with all three tests and, in the latter two tests, melanopsin photoreceptors.

RESULTS

Dark-adapted FST thresholds in LCA-CEP290 patients were cone mediated and elevated between 4.8 and 6.2 log units above the normal achromatic threshold. The FST threshold was not measurable in one patient. The rod-mediated transient pupillary light reflex (PLR) was absent in all but the youngest patient, where unreliable responses precluded PLR quantification. Cone-mediated transient PLRs were subnormal in five patients, and absent in another. Sustained melanopsin-mediated PLRs were measurable in all patients. Full-field LDT thresholds were elevated compared to normal controls, and were lower for short-wavelengh than for long-wavelength stimuli.

CONCLUSIONS

The FST thresholds and transient PLRs were cone mediated in our cohort LCA-CEP290 patients. Rod-mediated PLRs were undetectable, whereas melanopsin-mediated sustained responses were detected in all patients, suggesting a relative preservation of inner-retina function. The LDT elevations for the patients are somewhat paradoxical, given their subjective perception of photoaversion. Relative aversion to short-wavelength light suggests influence from melanopsin on LDTs in these patients.

Progress and prospects of next-generation sequencing testing for inherited retinal dystrophy

Next-generation sequencing, also known as massively paralleled sequencing, offers an unprecedented opportunity to study disease mechanisms of inherited retinal dystrophies: a dramatic change from a few years ago. The specific involvement of the retina and the manageable number of genes to sequence make inherited retinal dystrophies an attractive model to study genotype-phenotype correlations. Costs are reducing rapidly and the current overall mutation detection rate of approximately 60% offers real potential for personalized medicine and treatments. This report addresses the challenges ahead, which include: better understanding of the mutation mechanisms of syndromic genes in apparent non-syndromic patients; finding mutations in patients who have tested negative or inconclusive; better variant calling, especially for intronic and synonymous variants; more precise genotype-phenotype correlations and making genetic testing more broadly accessible.

Natural history of cone disease in the murine model of Leber congenital amaurosis due to CEP290 mutation: determining the timing and expectation of therapy

Background

Mutations in the CEP290 (cilia-centrosomal protein 290 kDa) gene in Leber congenital amaurosis (LCA) cause early onset visual loss but retained cone photoreceptors in the fovea, which is the potential therapeutic target. A cone-only mouse model carrying a Cep290 gene mutation, rd16;Nrl^−/−, was engineered to mimic the human disease. In the current study, we determined the natural history of retinal structure and function in this murine model to permit design of pre-clinical proof-of-concept studies and allow progress to be made toward human therapy. Analyses of retinal structure and visual function in CEP290-LCA patients were also performed for comparison with the results in the model.

Methods

Rd16;Nrl^−/− mice were studied in the first 90 days of life with optical coherence tomography (OCT), electroretinography (ERG), retinal histopathology and immunocytochemistry. Structure and function data from a cohort of patients with CEP290-LCA (n = 15; ages 7–48) were compared with those of the model.

Results

CEP290-LCA patients retain a central island of photoreceptors with normal thickness at the fovea (despite severe visual loss); the extent of this island declined slowly with age. The rd16;Nrl^−/− model also showed a relatively slow photoreceptor layer decline in thickness with ∼80% remaining at 3 months. The number of pseudorosettes also became reduced. By comparison to single mutant Nrl^−/− mice, UV- and M-cone ERGs of rd16;Nrl^−/− were at least 1 log unit reduced at 1 month of age and declined further over the 3 months of monitoring. Expression of GNAT2 and S-opsin also decreased with age.

Conclusions

The natural history of early loss of photoreceptor function with retained cone cell nuclei is common to both CEP290-LCA patients and the rd16;Nrl^−/− murine model. Pre-clinical proof-of-concept studies for uniocular therapies would seem most appropriate to begin with intervention at P35–40 and re-study after one month by assaying interocular difference in the UV-cone ERG.