Ophthalmic Genetics最新文献

Background and objectives: Congenital cone-rod synaptic disease (CRSD) belongs to a group of genetically and clinically heterogeneous retinal disorders. Pathogenic variants in the CABP4 gene coding for the calcium-binding protein four can lead to this condition. Several disease-causing variants lead to this condition. In support of this, our current study aimed to genetically characterize a consanguineous Lebanese family with two young siblings who show CRSD.

Results: Whole-exome sequencing identified a novel frameshift insertion in both affected siblings; c.363dup, p.(Lys122Glufs *21) in CABP4. The elder sibling carried a secondary homozygous missense variant; c.12575 G > A, p.(Arg4192His) in USH2A that is known to be associated with retinitis pigmentosa. CABP4 variant co-segregated with the phenotype in all the available family members. The ACMG guidelines classified CABP4 and USH2A variants as likely pathogenic and pathogenic, respectively. The secondary USH2A missense variant may lead to a more pronounced phenotype, necessitating an effective follow-up for better patient management.

Conclusion: The current findings highlight the involvement of CABP4 pathogenic variants in CRSD.

Background: Neural retina leucine zipper (NRL) is a crucial transcription factor that plays a key role in the development and differentiation of photoreceptor cells. A variant in this gene can cause a retinal phenotype known as Enhanced S cone Syndrome (ESCS). This study presents three novel autosomal recessive (ar) NRL variants and expands the clinical ophthalmic phenotype of NRL-associated retinopathy to include microphthalmia.

Methods: Investigations included electrodiagnostic testing, best corrected visual acuity (BCVA), optical coherence tomography (OCT), ultra-wide field autofluorescence (UWAF), fundus imaging, and visual fields. PubMed, Cochrane library and ClinVar database were used for literature search.

Results: Three patients (P1-3) from 2 different families with novel biallelic NRL variants were reported. P1 had novel homozygous likely-pathogenic NRL variant, p.(Glu86*). Genetic screening of both P2 and P3 identified a second and third novel heterozygous likely pathogenic variants, p.(Leu75Profs *19) and p.(Ser6Alafs *13). Multimodal imaging and functional studies in these patients were consistent with the classical features of ESCS with an additional feature of microphthalmia.

Conclusion: This study expands the genotype and phenotype of NRL-associated retinopathy and compares the ocular phenotype of our cohort with published NRL reports in the literature.

Introduction: Heimler syndrome is a rare autosomal recessive disorder at the mild end of the peroxisomal biogenesis disorders (PBDs), characterized by sensorineural hearing loss, amelogenesis imperfecta, and retinal dystrophy. Nail abnormalities affect a minority.

Case presentation: We present a 67-year-old woman diagnosed with non-syndromic retinitis pigmentosa in her fifties, who was later found to carry compound heterozygous variants in the PEX6 gene. Her medical history included prelingual hearing loss, early tooth decay, and brittle nails that were deemed unrelated for decades. Hearing loss and vision loss remained relatively stable up to last consultation.

Literature review: Our literature review includes 46 published Heimler syndrome cases with confirmed molecular diagnoses. Retinal dystrophy, predominantly of the rod-cone type with pigment clumping, was present in 89% of reported cases, with macular edema noted in 40%. Serum peroxisomal metabolite abnormalities seem to correlate with worse neurodevelopmental outcomes. There are no clear genotype-phenotype correlations, although residual peroxisomal function due to the presence of at least one missense, leaky splice site, or stable truncated allele explains the relatively mild phenotype for PBD.

Discussion: We underscore the importance to include syndromic disorders in the differential diagnosis of retinal dystrophy in older adults.

Background and objectives: The variety of ocular cell types involved in inherited retinal disease (IRD) necessitates the use of gene editing therapeutics which have generalizable components. In our study, we investigate the generalizable characteristics of non-engineered pegRNA design (PE2) for efficient, proof-in-principle gene correction of over 21 genes implicated in IRDs and associated syndromes. We use a single-transgene oligopool approach, comprising approximately 12,000 uniquely barcoded pegRNAs that target a synthetically integrated, 50 bp sequence motif, which faithfully recapitulate the disease context of their various counterpart IRDs. Using this approach, we perform a high throughput, pooled analysis of pegRNA characteristics across non- and ocular cell types to propose a cell-line agnostic set of pegRNA design guidelines.

Results: Briefly, we find that non-engineered pegRNA 3' extensions should mediate substitution-type edits and that the desired edit should be placed within five nucleotides upstream of the nick site induced by the Cas-endonuclease. Further, PBS and RTT lengths of at least 12 and 14 nucleotides, respectively, should be used and each non-engineered pegRNA 3' extension should obviate an initial templating cytosine nucleotide.

Conclusion: We establish a set of recommendations for the generalizable design of the non-engineered pegRNA 3' extension for the correction of several IRDs, enabling overall simplification of design parameters for PE2-based systems.

Background: Jeune syndrome is an autosomal recessive chondrodysplasia characterized by skeletal deformities and extra-skeletal organ involvement. Retinal astrocytic hamartomas (astrocytomas) are benign glial cell 10 15 Q1 tumors that are generally asymptomatic and diagnosed incidentally. The IFT74 gene is responsible for the formation of IFT proteins, which play a major role in ciliogenesis.

Case presentation: In this retrospective clinical laboratory observational study, an 18-year-old male with Jeune syndrome and night vision loss is presented. Fundus examination revealed bilateral optic discs with minimally blurred margins and bilateral retinal pigment epithelium changes in salt-pepper pattern in the peripheral retina. Additionally, a yellowish retinal astrocytoma was observed inferior to the optic disc in the left eye. Genetic analysis of the patient revealed a homozygous deletion in exon 2 of the IFT74 gene.

Conclusions: Our observations on this patient and some relationships between hamartoma and ciliopathies other than eye may potentially suggest a possible association between Jeune syndrome and retinal astrocytoma in the context of IFT74-related ciliopathies.

Background: Poland Syndrome is primarily characterized by musculoskeletal anomalies, such as unilateral absence of the sternocostal head of the pectoralis major. Ocular associations with Poland syndrome are rare, and ADAMTSL4 mutations, typically linked to autosomal recessive ectopia lentis, have not been previously associated with this condition.

Case: We describe a 20-month-old female with left-sided Poland syndrome who presented with intermittent right eye pain and a history of progressive corneal clouding. Examination revealed bilateral ectopia lentis, buphthalmos, and elevated intraocular pressure. Genetic testing identified a homozygous ADAMTSL4 variant (c.767_786del20), a novel association with Poland syndrome. The patient underwent successful bilateral lensectomy and anterior vitrectomy, and management of glaucoma was initiated. Her monochorionic diamniotic (MCDA) twin, also harboring the same ADAMTSL4 mutation, exhibited bilateral ectopia lentis and underwent surgical intervention.

Discussion: This report is the first to document an association between Poland syndrome and an ADAMTSL4 mutation, potentially suggesting a shared underlying defect in microfibril assembly. These findings expand our understanding of the genetic and developmental complexities of Poland syndrome and underscore the importance of early ophthalmological evaluation in such patients.

Conclusion: This case highlights the significance of genetic and ocular investigations in Poland syndrome, contributing to knowledge on its broader phenotypic spectrum and potential genetic etiologies. Further research is warranted to elucidate the role of ADAMTSL4 in microfibril-related anomalies.

Background: Oguchi disease, a rare form of congenital stationary night blindness (CSNB), is an autosomal recessive inherited retinal disorder (IRD) caused by pathogenic variants in the SAG gene, which encodes arrestin-1, a key protein in the phototransduction cascade.

Materials and methods: We present a case of a 35-year-old male with nyctalopia, progressive central vision loss, and refractory CME.

Case presentation: A 35-year-old male presented with nyctalopia and progressive central vision loss. Evaluation revealed attenuated retinal vessels, peripheral pigmentary changes, and severe CME bilaterally. Despite treatment with carbonic anhydrase inhibitors and NSAIDS, CME persisted. Initial genetic testing identified a heterozygous pathogenic SAG variant (p.Arg193*), raising suspicion for autosomal dominant RP. However, advanced long-read sequencing revealed a second pathogenic intronic SAG variant (c.-29+3A>G) in trans with the initial variant, confirming a diagnosis of autosomal recessive Oguchi disease.

Introduction: Inherited retinal diseases (IRDs) are clinically and genetically diverse conditions whose heterogeneity makes molecular diagnosis challenging. These challenges can lead to interpretation discordance which has a particular impact on gene-targeted therapies for IRD.

Methods: Discordance was evaluated in a clinical testing cohort and in ClinVar. 140 sequence variants identified through genetic testing in a cohort of pediatric participations with IRD were reclassified using the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP) guidelines for variant interpretation. ClinVar datasets from December 2, 2019 and January 3, 2022 for the gene RPE65 were analyzed for discordance.

Results: The discordance rate in the pediatric cohort was 22.2%. Discordance in ClinVar increased from 23.6% to 36.6%.

Discussion: Discordance in the pediatric cohort may have been impacted by subjective application of the ACMG/AMP guidelines and heterogeneity in IRD. Subjectivity in the guidelines, laboratory differences, and lack of interpretation review may have contributed to discordance in ClinVar. Work to improve interpretation for IRD should include better understanding of the genetic influences of IRD and optimization of the ACMG/AMP guidelines for this field.

Purpose: Familial exudative vitreoretinopathy (FEVR) is a category of vitreoretinal diseases with a broad phenotypic spectrum ranging from subclinical peripheral vascular changes to total retinal detachments. We report the clinical and molecular genetic findings in a 43-year-old patient whose ocular findings were consistent with retinitis pigmentosa but genetic testing indicative of FEVR.

Methods: The patient underwent serial examinations over a 12-year period that included fluorescein angiography, electroretinophysiologic testing, and molecular genetic testing using a retinal dystrophy panel.

Results: Repeated examinations demonstrated retinal pigmentary changes, arteriolar narrowing, and waxy disc pallor consistent with retinitis pigmentosa. Fluorescein angiography demonstrated peripheral non-perfusion, staining, and window defects, while electroretinogram and electro-oculogram were within normal limits. Genetic testing identified a novel heterozygous likely pathogenic nonsense variant in TSPAN12 gene, c.315T > A, p. (Cys105*).

Conclusions: This report highlights a novel TPSAN12 pathogenic variant causing atypical FEVR which manifests with a retinitis pigmentosa phenotype.

Purpose: Causal variants in the EYS gene are a major cause of retinitis pigmentosa (RP). However, treatment development for EYS-RP has been hindered due to the large size of the coding sequence and transcriptional complexity of the mRNA. Recently developed adenine base editors (ABEs), a form of CRISPR gene editing, offer another method to develop treatment for genetic diseases caused by G>A point mutations.

Materials and methods: This is a retrospective report describing a 73-year-old female with RP, who underwent clinical examination and retinal imaging. Genetic testing included sequencing of 111 known retinal genes and in silico prediction of pathogenicity of the identified variants. Availability and safety of ABE-mediated approaches to correct the patient variant were analyzed.

Results: Clinical evaluation revealed moderately advanced retinitis pigmentosa which had become symptomatic at 35 years of age. Genetic testing revealed a likely pathogenic homozygous EYS c.6192-1 G>A mutation, disrupting a canonical splice acceptor site. As a result, exon skipping with related frameshift deletion and introduction of a premature stop-codon in the forming mRNA is likely, leading to significantly truncated protein or total abolition of translated EYS. Multiple ABE approaches to correct the variant were detected.

Conclusions: In summary, we report a novel splice site variant in EYS in a patient with classical signs of RP. Further research is needed to develop safe and efficient treatment options for EYS-associated RP.