| Name | Francesca |
| Surname | Simonelli |
| Institution | Università degli Studi della Campania Luigi Vanvitelli |
| francesca.simonelli@unicampania.it | |
| Address | Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy |
Usher syndrome (USH) is a multisensory deficiency involving vision, hearing and the vestibular system. The purpose of this study is to report on the functional data (i.e. electroretinography, visual fields, visual acuity) of patients with retinitis pigmentosa (RP) due to Usher syndrome that were collected in a multicentre European study (TREATRUSH).
: Currently there is no medical treatment for X-linked retinoschisis (XLRS). In many retinal dystrophies, carbonic anhydrase inhibitors (CAIs) are effectively used to reduce cystoid macular edema. Prospective studies investigating the effect of CAIs in patients with XLRS are needed for the evaluation of their efficacy in this disease. The purpose of our work is to investigate the effects on macular morphology and function of oral CAIs used for the treatment of foveal lesions in patients with XLRS. : Nineteen patients with a clinical diagnosis of XLRS were enrolled and prescribed oral CAIs for six months. We evaluated the therapeutic effect of CAIs with: best-corrected visual acuity (BCVA), spectral-domain optical coherence tomography, microperimetry (MP) and multifocal electroretinography (mfERG). : We observed a significant improvement of BCVA (p-value = 0.013), central retinal thickness (p-value = 0.004) and macular sensitivity (p-value<0.001). Moreover, in regards to mfERG responses, an increase of P1 wave amplitude was observed in three of the six rings. : Our data supports the efficacy of oral CAIs for the treatment of macular cyst-like lesions in XLRS patients. The recovery of a normal retinal anatomy by means of oral CAIs could be useful to create the optimal circumstances for gene therapy. The increase in macular sensitivity and in P1 wave amplitude confirmed that MP and mfERG provide with an unbiased and more sensitive understanding of how macular function may respond to the use of CAIs. Therefore, we recommend the use of MP and mfERG to assess the effect of therapy in XLRS.
Retinal gene therapy with adeno-associated viral (AAV) vectors holds promises for treating inherited and noninherited diseases of the eye. Although clinical data suggest that retinal gene therapy is safe and effective, delivery of large genes is hindered by the limited AAV cargo capacity. Protein trans-splicing mediated by split inteins is used by single-cell organisms to reconstitute proteins. Here, we show that delivery of multiple AAV vectors each encoding one of the fragments of target proteins flanked by short split inteins results in protein trans-splicing and full-length protein reconstitution in the retina of mice and pigs and in human retinal organoids. The reconstitution of large therapeutic proteins using this approach improved the phenotype of two mouse models of inherited retinal diseases. Our data support the use of split intein-mediated protein trans-splicing in combination with AAV subretinal delivery for gene therapy of inherited blindness due to mutations in large genes.
To evaluate the disease progression in patients with clinical and genetic diagnoses of choroideremia during a long-term follow-up and to investigate the relationship between pathogenic variants in the CHM/REP1 gene and disease phenotypes.
Extracellular matrix molecular components, previously linked to multisystem syndromes include collagens, fibrillins and laminins. Recently, we described a novel multisystem syndrome caused by the c.9418G>A p.(V3140M) mutation in the laminin alpha-5 (LAMA5) gene, which affects connective tissues of all organs and apparatus in a three generation family. In the same family, we have also reported a myopic trait, which, however, was linked to the Prolyl 4-hydroxylase subunit alpha-2 (P4HA2) gene. Results of investigation on vitreous changes and their pathogenesis are reported in the present study.
Purpose The aim of this study is to report on the results of color vision testing in a European cohort of patients with Usher syndrome (USH). We describe the results in relation to Usher type (USH1, USH2), age and visual acuity. Methods and Methods The color vision of 220 genetically confirmed adult USH patients, aged 18-70 years, was analyzed with one of 3 methods: the Farnsworth D-15 Dichotomous test (D-15) along with the Lanthony desaturated 15 Hue tests (D-15d), the Roth 28-Hue test, or the Ishihara 14-plate test. Visual acuity was measured with either the ETDRS or the SNELLEN charts. The Confusion index, the Selectivity index and the Confusion angle were calculated for the panel tests and used for analysis. The number of plates that could not be read were analyzed for the Ishihara test. Results For the panel tests, the degree of color loss (Confusion index) is similar in both subtypes of USH, but the polarization of error scores (Selectivity index) is significantly lower in USH1 than USH2, showing more diffuse errors than those found in USH2. There is no significant correlation between logMAR visual acuity and the Confusion or the Selectivity indices. Additionally, we find a significant correlation between patient age and the degree and the polarity of the loss only in USH2. There was no difference between USH1 and USH2 in the results of the Ishihara test. Conclusions The examination of color vision in patients with USH, shows a significant difference in the pattern of color vision loss in USH1 and USH2 patients, but not in the severity of the loss. In USH2 we find a correlation between patient age and the degree and the polarity of the loss. These results may be due to differences in the pathogenesis of retinal dystrophy in USH1 and USH2.
To investigate the natural history of Stargardt disease over a multiyear follow-up.
Primary visual cortex (PVC) contains a retinotopic map in which the central visual field (CVF) is highly magnified compared to the peripheral field. Several studies have used functional magnetic resonance imaging (fMRI) in patients with macular degeneration to assess the reorganization of visual processing in relationship with the development of extrafoveal preferred retinal locus (PRL). We evaluated the functional response in PVC and its correlation with retinal parameters in patients with Stargardt disease due to ABCA4 mutations (STGD1).
We recently described a complex multisystem syndrome in which mild-moderate myopia segregated as an independent trait. A plethora of genes has been related to sporadic and familial myopia. More recently, in Chinese patients severe myopia (MYP25, OMIM:617238) has been linked to mutations in P4HA2 gene. Seven family members complaining of reduced distance vision especially at dusk underwent complete ophthalmological examination. Whole exome sequencing was performed to identify the gene responsible for myopia in the pedigree. Moderate myopia was diagnosed in the family which was associated to the novel missense variant c.1147A>G p.(Lys383Glu) in the prolyl 4-hydroxylase,alpha-polypeptide 2 (P4HA2) gene, which catalyzes the formation of 4-hydroxyproline residues in the collagen strands. In vitro studies demonstrated P4HA2 mRNA and protein reduced expression level as well as decreased collagen hydroxylation and deposition in mutated fibroblast primary cultures compared to healthy cell lines. This study suggests that P4HA2 mutations may lead to myopic axial elongation of eyeball as a consequence of quantitative and structural alterations of collagen. This is the first confirmatory study which associates a novel dominant missense variant in P4HA2 with myopia in Caucasian patients. Further studies in larger cohorts are advisable to fully clarify genotype-phenotype correlations.