Broadening the ocular phenotypic spectrum of ultra-rare BRPF1 variants: report of two cases.

INTRODUCTION: BRPF1 gene on 3p26-p25 encodes a protein involved in epigenetic regulation, through interaction with histone H3 lysine acetyltransferases KAT6A and KAT6B of the MYST family. Heterozygous pathogenic variants in BRPF1 gene are associated with Intellectual Developmental Disorder with Dysmorphic Facies and Ptosis (IDDDFP), characterized by global developmental delay, intellectual disability, language delay, and dysmorphic facial features. The reported ocular involvement includes strabismus, amblyopia, and refraction errors. This report describes a novel ocular finding in patients affected by variants in the BRPF1 gene. METHODS: We performed exome sequencing and deep ocular phenotyping in two unrelated patients (P1, P2) with mild intellectual disability, ptosis, and typical facies. RESULTS: Interestingly, P1 had a Chiari Malformation type I and a subclinical optic neuropathy, which could not be explained by variations in other genes. Having detected a peculiar ocular phenotype in P1, we suggested optical coherence tomography (OCT) for P2; such an exam also detected bilateral subclinical optic neuropathy in this case. DISCUSSION: To date, only a few patients with BRPF1 variants have been described, and none were reported to have optic neuropathy. Since subclinical optic nerve alterations can go easily undetected, our experience highlights the importance of a more detailed ophthalmologic evaluation in patients with BRPF1 variant.

Ciliopathy patient variants reveal organelle-specific functions for TUBB4B in axonemal microtubules.

Tubulin, one of the most abundant cytoskeletal building blocks, has numerous isotypes in metazoans encoded by different conserved genes. Whether these distinct isotypes form cell type- and context-specific microtubule structures is poorly understood. Based on a cohort of 12 patients with primary ciliary dyskinesia as well as mouse mutants, we identified and characterized variants in the TUBB4B isotype that specifically perturbed centriole and cilium biogenesis. Distinct TUBB4B variants differentially affected microtubule dynamics and cilia formation in a dominant-negative manner. Structure-function studies revealed that different TUBB4B variants disrupted distinct tubulin interfaces, thereby enabling stratification of patients into three classes of ciliopathic diseases. These findings show that specific tubulin isotypes have distinct and nonredundant subcellular functions and establish a link between tubulinopathies and ciliopathies.

The New Era of Therapeutic Strategies for the Treatment of Retinitis Pigmentosa: A Narrative Review of Pathomolecular Mechanisms for the Development of Cell-Based Therapies.

Retinitis pigmentosa, defined more properly as cone-rod dystrophy, is a paradigm of inherited diffuse retinal dystrophies, one of the rare diseases with the highest prevalence in the worldwide population and one of the main causes of low vision in the pediatric and elderly age groups. Advancements in and the understanding of molecular biology and gene-editing technologies have raised interest in laying the foundation for new therapeutic strategies for rare diseases. As a consequence, new possibilities for clinicians and patients are arising due to the feasibility of treating such a devastating disorder, reducing its complications. The scope of this review focuses on the pathomolecular mechanisms underlying RP better to understand the prospects of its treatment using innovative approaches.

A multidisciplinary approach to inherited retinal dystrophies from diagnosis to initial care: a narrative review with inputs from clinical practice.

BACKGROUND: Non-syndromic inherited retinal dystrophies (IRDs) such as retinitis pigmentosa or Leber congenital amaurosis generally manifest between early childhood and late adolescence, imposing profound long-term impacts as a result of vision impairment or blindness. IRDs are highly heterogeneous, with often overlapping symptoms among different IRDs, and achieving a definite diagnosis is challenging. This narrative review provides a clinical overview of the non-syndromic generalized photoreceptor dystrophies, particularly retinitis pigmentosa and Leber congenital amaurosis. The clinical investigations and genetic testing needed to establish a diagnosis are outlined, and current management approaches are discussed, focusing on the importance of the involvement of an interdisciplinary team from diagnosis and initial care to long-term follow-up and support. RESULTS: The effective management of IRDs requires a multidisciplinary, and ideally interdisciplinary, team of experts knowledgeable about IRDs, with experienced professionals from fields as diverse as ophthalmology, neuropsychiatry, psychology, neurology, genetics, orthoptics, developmental therapy, typhlology, occupational therapy, otolaryngology, and orientation and mobility specialties. Accurate clinical diagnosis encompasses a range of objective and subjective assessments as a prerequisite for the genetic testing essential in establishing an accurate diagnosis necessary for the effective management of IRDs, particularly in the era of gene therapies. Improvements in genome sequencing techniques, such as next-generation sequencing, have greatly facilitated the complex process of determining IRD-causing gene variants and establishing a molecular diagnosis. Genetic counseling is essential to help the individual and their family understand the condition, the potential risk for offspring, and the implications of a diagnosis on visual prognosis and treatment options. Psychological support for patients and caregivers is important at all stages of diagnosis, care, and rehabilitation and is an essential part of the multidisciplinary approach to managing IRDs. Effective communication throughout is essential, and the patient and caregivers' needs and expectations must be acknowledged and discussed. CONCLUSION: As IRDs can present at an early age, clinicians need to be aware of the clinical signs suggesting visual impairment and follow up with multidisciplinary support for timely diagnoses to facilitate appropriate therapeutic or rehabilitation intervention to minimize vision loss.

Microperimetry assessment in foveal hypoplasia: functional results in a series of pediatric patients.

OBJECTIVE: To study the relationships of functional and morphologic retinal parameters in a series of pediatric patients with varying degrees of foveal hypoplasia (FH). DESIGN: Monocentric observational retrospective study. PARTICIPANTS: Among 21 pediatric patients, 16 met inclusion criteria, having FH confirmed with spectral-domain optical coherence tomography (SD-OCT) scan METHODS: Data were analyzed retrospectively. Patients able to undergo macular microperimetry (MP) and SD-OCT examinations were included in the analysis. MP and SD-OCT outcomes were compared with FH grading and best-corrected visual acuity (BCVA) using Pearson's correlation. RESULTS: Thirty-one eyes from 16 patients (mean age 12.4 years) with different degrees of FH were analyzed. Two patients had grade 1, 7 had grade 2, 5 had grade 3, and 2 had grade 4 FH. Clinical nystagmus was present in 8 patients. The correlation between BCVA and SD-OCT data (-0.31) was lower than that found between BCVA and nystagmus (0.64), that for fixation index P1 (-0.60), as well as that for macular sensitivity (-0.63). CONCLUSIONS: Although limited by the small sample, our study confirms the feasibility of automated MP evaluation in pediatric patients with FH. The added value of this work is the provision of data on relationships between anatomic and functional macular measurements acquired with SD-OCT, MP, and BCVA in eyes with various degrees of FH. Larger prospective studies are necessary to confirm these results.

Optical Coherence Tomography Significance in Managing Early Onset of Optic Pathway Gliomas in Children Younger than 5 Years of Age-A Retrospective Study.

We aimed to investigate the significance of optical coherence tomography (SD-OCT) in managing pediatric optic pathway gliomas (OPGs) in children younger than 5 years of age. A retrospective monocentric study was conducted. SD-OCT scans were obtained using the handheld iVue system to assess peripapillary retinal nerve fibre layer (pRNFL) thickness at three time points: baseline (OCT1), end of treatment (OCT2), and at last follow-up (OCT3). We compared the median value of pRNFL (and interquartile range-IQR) at different follow-up times and in different sub-groups (stable disease-SD, partial response-PR, and progression disease-PD). Thirteen children younger than 5 years of age were included. The Median follow-up time was 3.9 years (IQR 1.2). Six patients showed a pRNFL change of more than 10% during follow-up. Seven patients showed PD during follow-up. Median pRNFL at baseline was 81.5 µm (IQR 31.5); median pRNFL at the end of treatment was 73 µm (IQR 33); median pRNFL at last follow-up was 72 µm (IQR 38.5). The mean pRNFL at baseline was significantly lower than the mean normative values. Only subjects with PD showed pRNFL change close to statistical significance. This study confirms the role of SD-OCT in managing OPGs for therapeutic decisions and strategy planning of visual rehabilitation.

Expanding the Spectrum of Oculocutaneous Albinism: Does Isolated Foveal Hypoplasia Really Exist?

Oculocutaneous albinism is an autosomal recessive disorder characterized by the presence of typical ocular features, such as foveal hypoplasia, iris translucency, hypopigmented fundus oculi and reduced pigmentation of skin and hair. Albino patients can show significant clinical variability; some individuals can present with only mild depigmentation and subtle ocular changes. Here, we provide a retrospective review of the standardized clinical charts of patients firstly addressed for evaluation of foveal hypoplasia and slightly subnormal visual acuity, whose diagnosis of albinism was achieved only after extensive phenotypic and genotypic characterization. Our report corroborates the pathogenicity of the two common TYR polymorphisms p.(Arg402Gln) and p.(Ser192Tyr) when both are located in trans with a pathogenic TYR variant and aims to expand the phenotypic spectrum of albinism in order to increase the detection rate of the albino phenotype. Our data also suggest that isolated foveal hypoplasia should be considered a clinical sign instead of a definitive diagnosis of an isolated clinical entity, and we recommend deep phenotypic and molecular characterization in such patients to achieve a proper diagnosis.

Treatment of Inherited Retinal Dystrophies with Somatic Cell Therapy Medicinal Product: A Review.

Inherited retinal dystrophies and retinal degenerations related to more common diseases (i.e., age-related macular dystrophy) are a major issue and one of the main causes of low vision in pediatric and elderly age groups. Advancement and understanding in molecular biology and the possibilities raised by gene-editing techniques opened a new era for clinicians and patients due to feasible possibilities of treating disabling diseases and the reduction in their complications burden. The scope of this review is to focus on the state-of-the-art in somatic cell therapy medicinal products as the basis of new insights and possibilities to use this approach to treat rare eye diseases.

Unusual presentation of early-onset X-linked retinoschisis: Report after 1 year of multimodal follow-up.

PURPOSE: To describe the unusual presentation, diagnosis, and clinical course of an early-onset X-linked infantile retinoschisis. CASE REPORT: A 6-month-old infant presented with strabismus and poor fixation. After the detection of bilateral intraretinal hemorrhage and diffuse dystrophic retinal pattern at indirect ophthalmoscopy, the patient received a complete evaluation under anesthesia. Retinal wide-field imaging, spectral domain optical coherence tomography, and electroretinogram were performed and revealed a retinoschisis involving the posterior pole and the inferior periphery in the right eye. In the left eye, an inferior retinal detachment extending to the macula was detected. Blood sample and genetic counseling were required in the strong suspicion of an inherited retinal dystrophy. Genetic tests confirmed the diagnosis of X-linked retinoschisis (RS1 gene mutation). After consultation with a pediatric vitreoretinal surgeon, a wait and see strategy was chosen. The follow up visits showed a surprisingly good natural course of the disease. CONCLUSION: X-linked retinoschisis is a well-known inherited retinal disease potentially affecting young children as early as 3 months old. In this case, the stunning presentation (diffuse retinal pigment epithelium dystrophic changes resembling a macular dystrophy) and the positive course of the disease (resolution of macular retinal detachment in the left eye and stability of schisis in the right eye) arise some interesting considerations about the necessity of an early surgical treatment.

The efficacy of biofeedback visual rehabilitation therapy in patients with infantile nystagmus syndrome: A retrospective study.

OBJECTIVE: To report fixation stability changes in patients with different forms of infantile nystagmus syndrome (INS), who have undergone a visual rehabilitation through biofeedback fixation training (BFT) with microperimetry (MP). DESIGN: Retrospective study. METHODS: Patients 6 to 12 years-old with INS who performed BFT with MP. Initially 10 once-weekly followed by eight twice-weekly sessions of BFT during a minimum of 6 months period were performed. Visual acuity (VA) and MP fixation stability indices were analyzed, including displacement from fixation point (P1, P2) and percentage of retinal loci used during fixation attempt (BCEA 63% and 95%). Statistical analysis was conducted at baseline (BL), 10 weeks (W10) and 6 months (M6). RESULTS: Twelve patients (mean age 8.9 years.) with INS completed the whole training session. All patients showed significant improvement in the mean BCEA fixation area (deg2): For BCEA@95% BL was 78.0, 46.1 at W10, and 27.4 at M6 (p-value = 0.004). For BCEA@63% BL was 27.3, 15.4 in W10, and 9.17 at M6 (p = 0.01). The ANOVA test for the FS indices of P1 and P2, as well as for BCVA showed no significant difference when compared at the same intervals. CONCLUSION: Fixation stability (FS) indices of BCEAs (63% and 95%) improved at W10 and M6, while P1 and P2 showed significant improvement at W10 but not at M6, probably because BCEA involves a much larger area than P1 and P2. VA did not show significant improvement at any time point.

Docosahexaenoic acid in ARSACS: observations in two patients.

BACKGROUND: Spastic ataxia of Charlevoix-Saguenay is a neurodegenerative condition due to mutations in the SACS gene and without a cure. Attempts to treatments are scarce and limited to symptomatic drugs. CASE PRESENTATION: Two siblings harboring biallelic variants in SACS underwent oral supplementation (600 mg/die) with docosahexaenoic acid (DHA), a well-tolerated dietary supplement currently used in SCA38 patients. We assessed over a 20 month-period clinical progression using disease-specific rating scales. CONCLUSIONS: DHA was safe over a long period and well-tolerated by the two patients; both showed a stabilization of clinical symptoms, rather than the expected deterioration, warranting additional investigations in patients with mutations in SACS.

Novel mutations in MFRP and PRSS56 are associated with posterior microphthalmos.

Background: Biallelic pathogenic variants in MFRP and PRSS56 genes can be responsible for nanophthalmos (NO) or posterior microphthalmos (PM). This study describes detailed clinical and molecular findings in a series of five patients affected by PM from four unrelated families.Materials and Methods: All patients underwent a complete ophthalmological and genetic evaluation. For proper and deep phenotyping a multimodal instrumental approach was used for all cases: B-scan ultrasound, spectral domain optical coherence tomography (SD-OCT), fundus retinal imaging and anterior segment data were obtained. Molecular analysis of PRSS56 and MFRP genes was performed with Next-Generation Sequencing (NGS) methodology and segregation analysis on parents and one affected sibling was performed with Sanger sequencing.Results: A very high hyperopia of +14.00D or more was the main refractive error and macular abnormalities were identified in all patients. Axial length ranged from 15.3 mm to 17.86 mm (mean 16.58 mm) and age at first presentation ranged from 6 to 36 months (mean 18 months). Anterior chamber depth was within normal values, according to age, while total axial length was severely reduced in all patients. All our patients met the diagnostic criteria for PM. Three patients, including a pair of siblings, carried compound heterozygous mutations in the PRSS56 gene; in the other two patients, one homozygous or two compound heterozygous mutations in the MFRP gene were detected.Conclusion: Our study describes four novel mutations in the PRSS56 gene and one in the MFRP gene in patients with non-syndromic posterior microphthalmos. Proper genotype-phenotype correlation and early diagnosis could lead to good functional results.

Visual assessment in Down Syndrome: The relevance of early visual functions.

BACKGROUND: Children with Down Syndrome (DS) have a high prevalence of ocular disorders, and even when ophthalmological deficits (i.e. refractive errors or strabismus) are corrected, visual acuity seems to have a different developmental trend compared to typical children. Unfortunately, there is no consensus about the age at which it is fundamental to perform a first comprehensive visual assessment in this population. AIMS: We analyzed early visual functions in a sample of 42 Italian children with DS, in order to achieve new insights for early surveillance and intervention. MATERIAL AND METHODS: DS children were evaluated with the Early Neurovisual Assessment, including Teller Acuity Cards (at 6, 12 and 18 months of age) and the Pediatric Ophthalmological Examination (within the 36th months of age). RESULTS: Visual acuity in our sample was lower than findings reported in the literature on healthy Italian children, but the values were within the confidence interval reported in previous studies on DS children. Moderate or severe refractive errors (> 3diopters) were present in five children (four had hyperopia and one myopia). Abnormalities in ocular motility were observed in 15 children and pathological findings for fundus oculi or lens were found in another eight. Furthermore, ophthalmological findings correlated with visual acuity at 18 months of age. CONCLUSION: According to our results, the Early Neurovisual Assessment at 18 months of life is a reliable tool for early detection of visual disorders in children with DS and it is useful for programming early intervention to promote their neurodevelopment.

Clinical and molecular studies in two new cases of ARSACS.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodevelopmental disorder characterized by the association of spastic ataxia and sensorimotor neuropathy. Additional features include retinal changes and cognitive impairment. Today, next-generation sequencing (NGS) techniques are allowing the rapid identification of a growing number of missense variants, even in less typical forms of the disease, but the pathogenic significance of these changes is often difficult to establish on the basis of classic bioinformatics criteria and genotype/phenotype correlations. Herein, we describe two novel cases of missense mutations in SACS. The two individuals were identified during the genetic screening of a large cohort of patients with inherited ataxias. We discuss how protein studies and specialized ophthalmological investigations could represent useful pointers for the interpretation of genetic data. Combination of these tools with NGS for rapid genotyping might help to identify new true ARSACS cases.

Airway stenting in a child with spondyloepiphyseal dysplasia congenita: 13-Year survival.

We describe the case of a boy with spondyloepiphyseal dysplasia congenita. At birth, he experienced severe respiratory distress necessitating tracheotomy. Endoscopy done because mechanical ventilation failed to resolve desaturations disclosed severe tracheo-bronchomalacia. A Polyflex silicone stent was placed in the trachea (replaced by Y-Dumon stent) and 2 Palmaz metallic stents in the mainstem bronchi (overlapped with 2 Jomed stents 5 years later). Airway stenting guaranteed a suitable respiratory status and allowed a child who was expected to die at birth, to reach 13.5 years old in good conditions.

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 Results of Photodynamic Therapy for Choroidal Neovascularization in Pediatric Patients with Best Vitelliform Macular Dystrophy.

PURPOSE: To report long-term results of photodynamic therapy (PDT) in young patients affected by Best vitelliform macular dystrophy (VMD) complicated by choroidal neovascularization (CNV). METHODS: We evaluated a group of 30 VMD patients with confirmed mutations in the BEST1 gene. Five of these patients had been diagnosed with CNV when younger than 15 years of age and three of them were treated by PDT. After the treatment they were followed for an average period of 77 months (range 62-99). RESULTS: In all the treated eyes visual acuity was stable during the first year of follow-up and then slowly improved even some years after the treatment. The improvement in visual acuity was associated with the development of fibrous tissue in the macula. CONCLUSIONS: PDT was a safe procedure in our series of pediatric patients with VMD complicated by CNV. It was followed by a CNV regression and a consequent improvement in visual acuity which continued to progress even several years after the treatment.

BEST1 sequence variants in Italian patients with vitelliform macular dystrophy.

PURPOSE: To analyze the spectrum of sequence variants in the BEST1 gene in a group of Italian patients affected by Best vitelliform macular dystrophy (VMD). METHODS: Thirty Italian patients with a diagnosis of VMD and 20 clinically healthy relatives were recruited. They belonged to 19 Italian families predominantly originating from central Italy. They received a standard ophthalmologic examination, OCT scan, and electrophysiological tests (ERG and EOG). Fluorescein and ICG angiographies and fundus autofluorescence imaging were performed in selected cases. DNA samples were analyzed for sequence variants of the BEST1 gene by direct sequencing techniques. RESULTS: Nine missense variants and one deletion were found in the affected patients; each patient carried one mutation. Five variants [c.73C>T (p.Arg25Trp), c.652C>T (p.Arg218Cys), c.652C>G (p.Arg218Gly), c.728C>T (p.Ala243Val), c.893T>C (p.Phe298Ser)] have already been described in literature while another five variants [c.217A>C (p.Ile73Leu), c.239T>G (p.Phe80Cys), c.883_885del (p.Ile295del), c.907G>A (p.Asp303Asn), c.911A>G (p.Asp304Gly)] had not previously been reported. Affected patients, sometimes even from the same family, occasionally showed variable phenotypes. One heterozygous variant was also found in five clinically healthy relatives with normal fundus, visual acuity and ERG but with abnormal EOG. CONCLUSIONS: Ten variants in the BEST1 gene were detected in a group of individuals with clinically apparent VMD, and in some clinically normal individuals with an abnormal EOG. The high prevalence of novel variants and the frequent report of a specific variant (p.Arg25Trp) that has rarely been described in other ethnic groups suggests a distribution of BEST1 variants peculiar to Italian VMD patients.

Novel RDH12 sequence variations in Leber congenital amaurosis.

Leber congenital amaurosis (LCA) designates a severe congenital retinal dystrophy generally inherited in an autosomal-recessive manner and accounting for 5% of inherited retinopathies. Its main clinical features are severe visual loss, sensory nystagmus, amaurotic pupils, and unrecordable electroretinographic response. LCA has been associated with sequence variations of 14 different genes; in approximately 30% of all cases pathogenic mutations remain to be determined. We report 2 patients with a clinical phenotype of LCA associated with novel mutations of the RDH12 gene.