Genotypic and Phenotypic Characterization of a Cohort of Patients Affected by Rod Cyclic Nucleotide Channel-Associated Retinitis Pigmentosa.

INTRODUCTION: Retinitis pigmentosa (RP), a heterogeneous inherited retinal disorder causing gradual vision loss, affects over 1 million people worldwide. Pathogenic variants in CNGA1 and CNGB1 genes, respectively, accounting for 1% and 4% of cases, impact the cyclic nucleotide-gated channel in rod photoreceptor cells. The aim of this study was to describe and compare genotypic and clinical characteristics of a cohort of patients with CNGA1- or CNGB1-related RP and to explore potential genotype-phenotype correlations. METHODS: The following data from patients with CNGA1- or CNGB1-related RP, followed in five Italian inherited retinal degenerations services, were retrospectively collected: genetic variants in CNGA1 and CNGB1, best-corrected visual acuity (BCVA), ellipsoid zone (EZ) width, fundus photographs, and short-wavelength fundus autofluorescence (SW-AF) images. Comparisons and correlation analyses were performed by first dividing the cohort in two groups according to the gene responsible for the disease (CNGA1 and CNGB1 groups). In parallel, the whole cohort of RP patients was divided into two other groups, according to the expected impact of the variants at protein level (low and high group). RESULTS: In total, 29 patients were recruited, 11 with CNGA1- and 18 with CNGB1-related RP. In both CNGA1 and CNGB1, 5 novel variants in CNGA1 and 5 in CNGB1 were found. BCVA was comparable between CNGA1 and CNGB1 groups, as well as between low and high groups. CNGA1 group had a larger mean EZ width compared to CNGB1 group, albeit not statistically significant, while EZ width did not differ between low and high groups A statistically significant correlation between EZ width and BCVA as well as between EZ width and age were observed in the whole cohort of RP patients. Fundus photographs of all patients in the cohort showed classic RP pattern, and in SW-AF images an hyperautofluorescent ring was observed in 14/21 patients. CONCLUSION: Rod CNG channel-associated RP was demonstrated to be a slowly progressive disease in both CNGA1- and CNGB1-related forms, making it an ideal candidate for gene augmentation therapies.

Atypic Retinitis Pigmentosa Clinical Features Associated with a Peculiar CRX Gene Mutation in Italian Patients.

Purpose: To describe an atypical phenotypic pattern of late-onset retinitis pigmentosa (RP) due to the same specific c.425A>G (p.Tyr142Cys) heterozygous mutation in the cone-rod homeobox gene (CRX gene) in two unrelated Italian patients. Case 1: A 67-year-old woman (P.P.) was incidentally diagnosed with sector RP at the age of 50. The patient was initially asymptomatic and did not have any family history of retinal dystrophy. Fundus examination showed the presence of typical retinal pigmentary deposits with a peculiar pericentral/sector distribution. Genomic sequencing disclosed the missense mutation c.425A>G (p.Tyr142Cys) in the CRX gene. During the follow-up period of 7 years, the patient maintained good visual acuity and complained only of mild symptoms. Case 2: A 76-year-old man (P.E.) presented with nyctalopia and visual field constriction since the age of 50. Fundus examination showed the presence of retinal pigment deposits with a concentric pericentral and perimacular pattern. A full-field electroretinogram (ffERG) showed extinguished scotopic responses and reduced abnormal photopic and flicker cone responses. Genomic sequencing identified the same missense mutation, c.425A>G (p.Tyr142Cys), in the CRX gene. Similarly to the first case, during the whole follow-up of 7 years, the visual acuity remained stable, as did the visual field and the patient's symptoms. Conclusions: We report the first cases of late-onset retinitis pigmentosa related to a specific heterozygous CRX gene mutation in exon 4. We also report two atypical phenotypic RP patterns related to mutations in the CRX gene.

Clinical and genetic findings in Italian patients with sector retinitis pigmentosa.

Purpose: To describe clinical and genetic features in a series of Italian patients with sector retinitis pigmentosa (sector RP). Methods: Fifteen patients with sector RP were selected from the database of Hereditary Retinal Degenerations Referring Center of Careggi Hospital (Florence, Italy). Eleven patients from five independent pedigrees underwent genetic analysis with next-generation sequencing (NGS) confirmed with Sanger sequencing. The diagnosis of sector RP was based on the detection of topographically limited retinal abnormalities consistent with corresponding sectorial visual field defects. Best-corrected visual acuity (BCVA), fundus color pictures as well as fundus autofluorescence (FAF), spectral domain-optical coherence tomography (SD-OCT), full-field electroretinography (ERG), and 30-2 Humphrey visual field (VF) data were retrospectively collected and analyzed. Results: For the 30 eyes, the mean BCVA was 0.05 ± 0.13 logMAR, and the mean refractive error was -0.52 ± 1.89 D. The inferior retina was the most affected sector (86.7%), and the VF defect corresponded to the affected sector. FAF showed a demarcation line of increased autofluorescence between the healthy and affected retina, corresponding on SD-OCT to an interruption of the ellipsoid zone (EZ) band in the diseased retina. Dark-adapted ERG amplitudes were decreased in comparison to normative values. In five unrelated families, the sector RP phenotype was associated with sequence variants in the RHO gene. The same mutation c.568G>A p.(Asp190Asn) was found in nine patients of four families. Conclusions: Typical sector RP is a mild form of RP characterized by preserved visual acuity with limited retinal involvement and, generally, a more favorable prognosis than other forms of RP.

Outcome and genetic analysis of patients affected by retinal capillary hemangioblastoma in von Hippel Lindau syndrome.

Purpose: To describe genetic analysis, treatment results, and complications of patients affected by retinal capillary hemangioblastoma (RCH) in von Hippel Lindau (VHL) syndrome. Methods: We collected 17 patients with VHL syndrome, who underwent a molecular test and an ophthalmic evaluation at the Eye Clinic of the University Hospital of Florence from January 2005 to February 2020. We focused on eyes showing RCHs examined using color fundus photographs, fluorescein angiography, and optical coherence tomography. Results: Eight eyes of six patients (6/17; 35%) showed RCHs at the fundoscopic examination. All RCHs were treated with laser therapy. Three eyes underwent episcleral surgery, one eye showing vitreous hemorrhage received three intravitreal (IV) anti-VEGF injections and three cryotherapy procedures, and one eye underwent vitrectomy. In patients with RCHs, five were characterized by a truncating mutation of the VHL protein, and one patient showed a missense mutation. We have reported two VHL mutations not reported in literature. Conclusions: Patients with multiple RCHs, who developed RCH secondary effects, showed truncating mutations of the VHL protein. We recommend early screening and close monitoring, especially if RCHs are detected at presentation, for every patient with VHL syndrome independently of the results of the molecular test for a missense or a truncating mutation in VHL.

CHOROIDAL VASCULARITY INDEX IN YOUNG CHOROIDEREMIA PATIENTS.

PURPOSE: To evaluate choroidal features in young patients affected by choroideremia (CHM). METHODS: Young CHM patients and control subjects were recruited at the Eye Clinic in Florence. High-resolution choroidal imaging was obtained using swept-source optical coherence tomography with long optical coherence tomography scans (12 × 9 mm optical coherence tomography scans). We considered the subfoveal choroidal area within 9 mm of the optic disk in the horizontal plane and the subfoveal choroidal area within a 3-mm diameter centered over the fovea. The subfoveal choroidal thickness, total choroidal area, luminal area, stromal area, and choroidal vascularity index were assessed using the "ImageJ" software in both groups. RESULTS: Eight patients (16 eyes; mean age, 19.3 ± 5.2 years) and seven control subjects (14 eyes; mean age, 19.0 ± 5.0 years) were included in this study. Best-corrected visual acuity was 20/20 in both eyes of seven CHM patients and in all control subjects and 20/25 in both eyes in one CHM patient. Mean subfoveal choroidal thickness did not differ between CHM patients and control subjects. Luminal area9mm, stromal area9mm, and total choroidal area9mm were reduced in patients compared with the control group. Luminal area3mm, stromal area3mm, and total choroidal area3mm did not differ between patients and control subjects. Choroidal vascularity index9mm and choroidal vascularity index3mm were not different between patients and control subjects. CONCLUSION: There are no differences in the choroidal vascularity index between young CHM patients and control subjects; this result suggests a simultaneous, proportional impairment of both the stromal and vascular components of the choroid in the early stages of the disease.

Inherited Retinal Diseases Due to RPE65 Variants: From Genetic Diagnostic Management to Therapy.

Inherited retinal diseases (IRDs) are a heterogeneous group of conditions that include retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) and early-onset severe retinal dystrophy (EO[S]RD), which differ in severity and age of onset. IRDs are caused by mutations in >250 genes. Variants in the RPE65 gene account for 0.6-6% of RP and 3-16% of LCA/EORD cases. Voretigene neparvovec is a gene therapy approved for the treatment of patients with an autosomal recessive retinal dystrophy due to confirmed biallelic RPE65 variants (RPE65-IRDs). Therefore, the accurate molecular diagnosis of RPE65-IRDs is crucial to identify 'actionable' genotypes-i.e., genotypes that may benefit from the treatment-and is an integral part of patient management. To date, hundreds of RPE65 variants have been identified, some of which are classified as pathogenic or likely pathogenic, while the significance of others is yet to be established. In this review, we provide an overview of the genetic diagnostic workup needed to select patients that could be eligible for voretigene neparvovec treatment. Careful clinical characterization of patients by multidisciplinary teams of experts, combined with the availability of next-generation sequencing approaches, can accelerate patients' access to available therapeutic options.

Pattern dystrophy-like changes and coquille d'oeuf atrophy in elderly patients affected by pseudoxanthoma elasticum.

PURPOSE: To evaluate the retinal features of elderly patients affected by pseudoxanthoma elasticum (PXE). MATERIALS AND METHODS: This is a retrospective case series of 62 eyes of 31 elderly PXE patients (age > 50 years). Clinical data, ultra-widefield fundus imaging (color, red-free (RF), infra-red imaging (IR), fundus autofluorescence (FAF)), and OCT examinations were collected. Diagnosis was confirmed by genetic testing or skin biopsy. RESULTS: Thirty-one patients (10 males and 21 females (mean age 61.3 years, range 50-74 years)) were included in our study. Visual acuity ranged from 20/20 Snellen equivalent to 20/200. The mean follow-up was 66.4 ± 20.7 months (range 10-88). Pattern dystrophy-like changes (PD) (52 eyes of 26 patients, 83.8%) and atrophy resembling the "diffuse trickling" pattern described in geographic atrophy were present in the majority of patients. Twenty-three eyes of 12 patients (67.6%) had peripapillary atrophy, 9 eyes of 5 patients (26.4%) macular atrophy, 6 eyes of 3 patients (17.6%) displayed posterior pole atrophy and in 6 eyes of 3 patients (17.6%), atrophy could be detected beyond the vascular arcades (mid-peripheral atrophy). End-stage atrophy covered the entire area indicated as "coquille d'oeuf" (eggshell). Choroidal neovascularization occurred in 49 eyes of 26 patients (94.2%) with PD and in 6 eyes of 3 patients (60%) without PD. Genetic examinations were available for 29 patients (29/31, 93.5%). CONCLUSIONS: The elderly PXE patients were characterized by pattern dystrophy-like changes with more or less extensive atrophy, progressive over time, which in some cases affected the whole area of the coquille d'oeuf during the course of the disease.

Novel clinical findings in autosomal recessive NR2E3-related retinal dystrophy.

PURPOSE: To evaluate the clinical phenotype of autosomal recessive NR2E3-related retinal dystrophy. METHODS: We retrospectively studied 11 patients carrying out at least 2 NR2E3 mutations; they had undergone comprehensive ophthalmological examination, fundus photography, optical coherence tomography, electrophysiological testing, and visual field at the Regional Reference Center for Hereditary Retinal Degenerations of the Eye Clinic in Florence. RESULTS: Five females and six males with a diagnosis of NR2E3-related retinal dystrophy were included in the study. All patients complained of nyctalopia. Visual acuity ranged from 0.00 logMAR to hand motion. Two patients presented bull's eye maculopathy, and one of these was characterized by a triple hyper-autofluorescent ring at the fundus autofluorescence examination. Three patients showed small yellowish dots and spots at the mid-periphery. One patient was characterized by widespread subretinal drusenoid deposits (SDD) at the posterior pole. Four patients showed vitreous abnormalities. Optical coherence tomography (OCT) examinations detected variable degrees of abnormal retinal lamination and schitic changes. Seven patients were compound heterozygous and four were homozygous for mutations in NR2E3. CONCLUSIONS: Our study confirmed high variable phenotype in autosomal recessive NR2E3-related retinal dystrophy. Bull's eye maculopathy, subretinal drusenoid deposits, and foveal hypoplasia represent novel clinical findings in NR2E3-related retinal dystrophy. Macular involvement was detectable in all the patients, and the abnormal foveal avascular zone (FAZ) supports the role of NR2E3 in retinal development.

Optical coherence tomography (OCT) features of cystoid spaces in choroideremia (CHM).

PURPOSE: To investigate the prevalence and features of cystoid spaces (CS) in patients with confirmed genetic diagnosis of choroideremia (CHM) using swept source optical coherence tomography (OCT). METHODS: We retrospectively reviewed CHM patients examined at the Regional Reference Center for Hereditary Retinal Degenerations at the Eye Clinic in Florence. We took into consideration genetically confirmed CHM patients with ophthalmological and swept source optical coherence tomography (OCT) examinations. The presence/absence and location of cystoid spaces in the retina of each eye were reported. RESULTS: A total of 42 eyes of 21 CHM patients were included in our series. The average age of the patients was 36.5 ± 20.1 (range, 13-73 years). The average best-corrected visual acuity (BCVA) for all patients was 0.63 ± 1.00 logMar (range, 0-2,80). CS were present in 15 eyes of eight patients (8/21, 38%). In all cases, CS were located in inner nuclear layer (INL); in five eyes of three patients, CS were detected also in ganglion cell layer (GCL). CS appeared as microcistoyd abnormalities and were detected in retinal areas characterized by retinal pigment epithelium (RPE) and outer retinal layers atrophy at the transition zone. CONCLUSIONS: Cystoid spaces in choroideremia showed peculiar features; they are clusters of small-size extrafoveal degenerative cysts mainly located in inner nuclear layer at the transition zone where outer retinal layers and RPE are severely damaged.

Peculiar Clinical Findings in Young Choroideremia Patients: A Retrospective Case Review.

PURPOSE: To report peculiar clinical findings in young choroideremia (CHM) patients. METHODS: We retrospectively reviewed young (age <20 years at the first evaluation) CHM patients examined at the Regional Reference Center for Hereditary Retinal Degenerations at the Eye Clinic in Florence between 2012 and 2018. We took into consideration patients with ophthalmological examinations, fundus color photographs, fundus autofluorescence (FAF) images, optical coherence tomography (OCT) scans, full-field electroretinograms, and Goldmann visual fields. RESULTS: In our series, we studied 8 young CHM patients (average age 13.8 years, median age 12.5, range 10-20) for a total of 16 eyes. Visual acuity (VA) was 20/20 in 7 patients and 20/25 in both eyes of 1 patient. We identified a peculiar central FAF pattern (detectable in 3 patients), characterized by reduced central hypo-autofluorescence. Long OCT scans showed different forms of parapapillary retinal involvement from the mildest to the most severe form when the macula is still preserved. In 3 patients, at the time of atrophic changes at the posterior pole, it was possible to detect a progressive reduction of foveal pigmentation during follow-up. We found mutations of the CHM gene in all 6 patients who had been screened. CONCLUSIONS: CHM is a progressive retinal disorder which involves both the peripheral and the central retina. Using a multimodal imaging approach, we described peculiar central abnormalities underlying the early involvement of the central retina in young CHM patients with a good VA.

Peripapillary comet lesions and comet rain in PXE-related retinopathy.

PURPOSE: To study peripapillary comet lesions (PCL) in Italian patients affected with pseudoxanthoma elasticum (PXE). METHODS: Retrospective review of fundoscopic and swept-source (SS) optical coherence tomography (OCT) images of patients with PXE examined at the Regional Reference Center for Hereditary Retinal Degenerations at the Careggi Teaching Hospital of Florence from 2012 to 2017. RESULTS: From 148 eyes of 74 patients affected with PXE, we identified 24 eyes of 14 patients (11 were female) with a mean age of 39 years (range, 20-58 years) characterized by peripapillary comet lesions. Of these 24 eyes, 15 eyes (of 10 patients) were characterized by comet rain. The smallest comet lesion at the OCT examination appeared as a focal roundish hyper-reflective alteration at the level of the outer retinal segments and RPE-Bruch's membrane complex; the larger lesions appeared as circular and ovoid structures with hyper-reflective borders in the outer nuclear layer. CONCLUSION: The comet lesion formation process involves the outer layers of the retina and RPE/Bruch's membrane complex. It consists of a degenerative/rearrangement process of the photoreceptors which occurs in an area of focal altered RPE/Bruch's membrane resembling the outer retinal tubulation.

Retinal dystrophy and subretinal drusenoid deposits in female choroideremia carriers.

PURPOSE: To describe clinical and molecular characteristics in a group of Italian female choroideremia (CHM) carriers and report fundus patterns. METHODS: We retrospectively studied 11 female carriers belonging to six CHM families examined at the Regional Reference Center for Hereditary Retinal Degenerations at the Eye Clinic in Florence. We took into consideration patients with a comprehensive ophthalmological examination, fundus photography, optical coherence tomography (OCT), full field electro-retinography (ERG), and visual field (VF). All patients were screened for mutations of the CHM gene. RESULTS: Fundus examination revealed retinal abnormalities in all female carriers (11/11) in the study; in particular four fundus patterns were identified: pattern A (RPE dystrophy involving only the peripheral retina), pattern B (RPE dystrophy involving the peripheral retina and the posterior pole with small hypo-pigmented RPE areas), pattern C (RPE dystrophy involving the peripheral retina and the posterior pole with small yellowish well-defined dots), and pattern D (RPE dystrophy involving the peripheral retina and the posterior pole with large hypo-pigmented RPE areas and well-defined yellowish dots). Pattern D was characterized by widespread macular subretinal drusenoid deposits (SDD). Half of the observed mutations were novel mutations. A genotype-phenotype correlation was not identified. CONCLUSIONS: Retinal dystrophy and SDD were detected in our female CHM carriers, and fundus patterns have been described in this study. The recognition of specific fundoscopic patterns may permit a correct diagnosis, an appropriate molecular investigation and genetic counseling.

Case report of an atypical early onset X-linked retinoschisis in monozygotic twins.

BACKGROUND: X-linked Retinoschisis (XLRS) is one of the most common macular degenerations in young males, with a worldwide prevalence ranging from 1:5000 to 1:20000. Clinical diagnosis of XLRS can be challenging due to the highly variable phenotypic presentation and limited correlation has been identified between mutation type and disease severity or progression. CASE PRESENTATION: We report the atypical early onset of XLRS in 3-month-old monozygotic twins. Fundus examination was characterized by severe bullous retinal schisis with pre-retinal and intraretinal haemorrhages. Molecular genetic analysis of the RS1 was performed and the c.288G > A (p. Trp96Ter) mutation was detected in both patients. CONCLUSIONS: Early onset XLRS is associated with a more progressive form of the disease, characterized by large bullous peripheral schisis involving the posterior pole, vascular abnormalities and haemorrhages. The availability of specific technology permitted detailed imaging of the clinical picture of unusual cases of XLRS. The possible relevance of modifying genes should be taken into consideration for the future development of XLRS gene therapy.

Long-Term Follow-Up of Choroidal Neovascularization due to Angioid Streaks with pro re nata Intravitreal Anti-VEGF Treatment.

PURPOSE: To evaluate the long-term outcomes of intravitreal anti-vascular endothelial growth factor (VEGF) drugs with a pro re nata (PRN) regimen for the treatment of choroidal neovascularization (CNV) secondary to angioid streaks (AS). METHODS: This is a retrospective, multicenter, noncomparative case series of consecutive AS eyes affected by treatment-naïve CNV. A complete ophthalmologic examination was performed every 30-45 days after the loading phase, including fluorescein angiography and/or optical coherence tomography. RESULTS: In all, 52 eyes of 39 patients were treated with intravitreal bevacizumab and/or ranibizumab and followed up for a mean of 33.8 months. The best corrected visual acuity at baseline was 20/40, and it deteriorated by an average of 6.8 ETDRS letters per year (p < 0.001). We performed an average of 5.1, 6.5, and 6.8 injections at the 1-, 2-, and 3-year follow-up, respectively. CONCLUSIONS: Intravitreal anti-VEGF drugs in a PRN regimen with close monitoring appear to slow the progression of CNV in AS, but they do not prevent the affected eyes from progressive visual loss.

En face OCT in Stargardt disease.

PURPOSE: To evaluate the structural features of the macular region by enface OCT imaging in patients with clinical diagnosis of Stargardt disease, confirmed by the detection of ABCA4 mutations. METHODS: Thirty-two STGD patients were included in the study for a total of 64 eyes. All patients received a comprehensive ophthalmological examination, color fundus photography, fundus auto-fluorescence imaging and OCT. Five OCT scans were considered: ILM and RPE scans (both automatically obtained from the instrument), above-RPE slab, photoreceptor slab and sub-RPE slab (these last three manually obtained). RESULTS: ILM scans showed evident radial folds on the retinal surface in 8/64 eyes (12.5 %). In 6 of the 7 patients, these vitreo-retinal interface abnormalities were unilateral. The photoreceptor slab showed some macular alterations ranging from dis-homogeneous, hypo-reflective abnormalities (7/64 eyes, 11 %) to a homogeneous, well-defined, roundish, hypo-reflective area (17/64 eyes, 27 %) in all the eyes. The sub-RPE slab showed a centrally evident, hyper-reflective abnormality in 58/64 eyes (90.6 %). Superimposing the sub-RPE slab over the images corresponding to the photoreceptor slab, the area of the photoreceptor atrophy sharply exceeded that of the RPE atrophy (44/46 eyes, 96 %). CONCLUSION: Enface OCT proved to be a clinically useful tool for the management of STGD patients, illustrating in vivo the structural abnormalities of the different retinal layers.

Dietary profile of patients with Stargardt's disease and Retinitis Pigmentosa: is there a role for a nutritional approach?

BACKGROUND: Stargardt's disease (STGD) and Retinitis Pigmentosa (RP) are inherited retinal degenerations that may be affected, in opposite way, by diet. METHODS: Dietary profile was assessed in 24 patients with STGD and in 56 patients with RP. We documented in only 6 out of 24 (25%) STGD patients a daily intake of vitamin A within the recommended range while 14/24 (58.3%) reported a high daily intake and 4/24 (16.7%) showed a low daily intake. With regard to RP, 4/56 (7.1%) reported to be within the recommended range, 37/56 (66.1%) reported high daily intake and 15/56 (26.8%) showed low daily intake of vitamin A. RESULTS: Interestingly, STGD patients with low vitamin A intake (<600 µg RAE/day) showed significantly better visual acuity with respect to those introducing higher intake of vitamin A. CONCLUSION: The present study suggests insuitable nutrient intakes among patients with STGD and RP, especially for daily intake of vitamin A. The results may be used to provide tailored nutritional interventions in these patients.

Computer-Assisted Evaluation of Retinal Vessel Diameter in Retinitis Pigmentosa.

PURPOSE: The evaluation of retinal vessel attenuation is very subjective and not sufficiently reliable in patients with retinitis pigmentosa (RP). We tested semiautomatic software capable of obtaining real-time measurements of vessel diameter. METHODS: Retinal vessel diameter was calculated in 25 RP subjects and in 20 healthy controls. The Mann-Whitney test was used to compare the average values of RP patients with those of controls and subgroups of RP patients with different clinical features. RESULTS: The retinal vessel diameter was significantly smaller in RP patients than in controls (p < 0.001). In particular, vessel diameters were smaller in older subjects, in patients with worse ERG responses, and in patients with more severe visual field loss. CONCLUSIONS: Computer-assisted analysis of retinal fundus pictures may be helpful in the diagnosis of RP and in monitoring disease progression.

MYO7A and USH2A gene sequence variants in Italian patients with Usher syndrome.

PURPOSE: To analyze the spectrum of sequence variants in the MYO7A and USH2A genes in a group of Italian patients affected by Usher syndrome (USH). METHODS: Thirty-six Italian patients with a diagnosis of USH were recruited. They received a standard ophthalmologic examination, visual field testing, optical coherence tomography (OCT) scan, and electrophysiological tests. Fluorescein angiography and fundus autofluorescence imaging were performed in selected cases. All the patients underwent an audiologic examination for the 0.25-8,000 Hz frequencies. Vestibular function was evaluated with specific tests. DNA samples were analyzed for sequence variants of the MYO7A gene (for USH1) and the USH2A gene (for USH2) with direct sequencing techniques. A few patients were analyzed for both genes. RESULTS: In the MYO7A gene, ten missense variants were found; three patients were compound heterozygous, and two were homozygous. Thirty-four USH2A gene variants were detected, including eight missense variants, nine nonsense variants, six splicing variants, and 11 duplications/deletions; 19 patients were compound heterozygous, and three were homozygous. Four MYO7A and 17 USH2A variants have already been described in the literature. Among the novel mutations there are four USH2A large deletions, detected with multiplex ligation dependent probe amplification (MLPA) technology. Two potentially pathogenic variants were found in 27 patients (75%). Affected patients showed variable clinical pictures without a clear genotype-phenotype correlation. CONCLUSIONS: Ten variants in the MYO7A gene and 34 variants in the USH2A gene were detected in Italian patients with USH at a high detection rate. A selective analysis of these genes may be valuable for molecular analysis, combining diagnostic efficiency with little time wastage and less resource consumption.

Optical coherence tomography (OCT) and OCT-angiography in syndromic versus non-syndromic USH2A-associated retinopathy.

PURPOSE: To compare non-syndromic and syndromic forms of USH2A-related retinitis pigmentosa (RP) by means of structural optical coherence tomography (OCT) and OCT-angiography (OCTA). METHODS: Observational, cross-sectional, multicenter study. All patients underwent best corrected visual acuity (BCVA) measurement, OCT (Spectralis HRA + OCT, Heidelberg Engineering) and OCTA (OCT DRI Topcon Triton, Topcon Corporation). We compared subfoveal choroidal thickness (SCT), choroidal vascularity index (CVI), presence of cystroid macular edema (CME), macular vessel density (VD) at the superficial and deep capillary plexa, as well as VD of the radial peripapillary capillary (RPC) network, between syndromic and non-syndromic patients with USH2A-associated retinopathy. RESULTS: Thirty-four eyes from 18 patients (7 females) were included. Thirteen patients (72.2%) were affected by Usher syndrome type 2, whereas the remaining 5 subjects (27.8%) had non-syndromic retinitis pigmentosa (nsRP). Syndromic patients were younger than nsRP (p = 0.01) and had a worse visual acuity than those with the exclusively retinal phenotype. Patients with Usher syndrome type 2 had a higher prevalence of CME and a thicker choroid compared to nsRP, although these results were not statistically significant (p = 0.775 and p = 0.122, respectively). Similarly, none of the other quantitative OCT and OCTA parameters was statistically different between the two groups. CONCLUSIONS: Despite their younger age, patients with Usher syndrome type 2 displayed similar choroidal and microvascular changes compared to those with nsRP.