Search Results (17)

Sensenbrenner syndrome, or cranioectodermal dysplasia (CED), is a rare autosomal recessive ciliopathy characterized by craniofacial, skeletal, ectodermal, and renal abnormalities. Ocular involvement, though infrequent, can include retinal dystrophy with early-onset visual impairment. We report a case of a 2-year-old boy with classic clinical features of CED and significant ocular findings. Genetic testing revealed two novel compound heterozygous variants in the WDR19 gene—c.1778G>T and c.3536T>G—expanding the known mutational spectrum associated with this condition. Ophthalmologic evaluation demonstrated bilateral optic nerve hypoplasia, high hyperopia, and severely reduced ERG responses, consistent with global retinal dysfunction. Fundoscopy revealed optic disk pallor, vessel attenuation, and peripheral pigment changes. Multisystem findings included postaxial polydactyly, brachydactyly, short stature, hypotonia, and stage 2 chronic kidney disease. This case highlights the importance of early ophthalmologic screening in suspected CED and underscores the utility of ERG in detecting early retinal involvement. The identification of two previously undescribed WDR19 variants contributes to genotype–phenotype correlation in CED and emphasizes the need for ongoing documentation to guide diagnosis, management, and genetic counseling. Full article

Pontocerebellar hypoplasia is a rare neurodegenerative syndrome characterized by severe hypoplasia or atrophy of pons and cerebellum that may be associated with other brain malformations, microcephaly, optic nerve atrophy, dystonia, ataxia and neuromuscular disorders. At this time, there are 17 variants of PCH distinguished by clinical presentation and distinctive radiological and biochemical features in addition to pontine and cerebellar hypoplasia. PCH1 is defined as PCH variant associated with anterior horn degeneration in the spinal cord with muscle weakness and hypotonia, and is associated with recessive variants in genes VRK1, EXOSC3, EXOSC8, EXOSC9 and SLC25A46. Neuromuscular manifestations may clinically present as amyotrophic lateral sclerosis (ALS), motor neuropathy (HMN) or neuronopathy (non-5q spinal muscular atrophy; SMA) or sensorimotor polyneuropathy (HMSN). Physiologic functions of PCH1-associated genes include regulation of RNA metabolism, mitochondrial fission and neuronal migration. Overall, complex phenotypes associated with PCH1 gene variants ranging from PCH and related neurodevelopmental disorders combined with neuromuscular disorders to isolated neuromuscular disorders have variable outcomes with isolated neuromuscular disorders typically having later onset with better outcomes. Improved understanding of pathogenesis of pontocerebellar hypoplasia and its association with motor neuronopathies and peripheral neuropathies may provide us with valuable insights and lead to potential new therapeutic targets for neurodegenerative disorders. Full article

Background and Objectives: Pathogenic variants in the PAX2 gene have been associated with a spectrum of eye and kidney disorders, ranging from papillorenal syndrome (known as renal coloboma syndrome) to isolated nephrosis without kidney morphological anomalies (focal segmental glomerulosclerosis), inherited in an autosomal dominant manner. However, due to the growing number of reports of pathogenic variants in the PAX2 gene, it is observed that genotype–phenotype correlation is not always consistent. We present patients from two unrelated families with PAX2 pathogenic variants c.685C>T and c.250G>A, highlighting the diverse phenotypic expression of PAX2-related disorders. Materials and Methods: We analyzed clinical and genetic data from two families who were tested for genomic abnormalities using targeted next-generation sequencing and Sanger sequencing for segregation analysis. Results: In Family A, a 27-year-old male presented with chronic kidney disease stage 3, proteinuria, and multicystic kidney dysplasia diagnosed at 11 years old. An ophthalmologic examination revealed bilateral optic nerve dysplasia. In Family B, a 6-year-old female and her 4-year-old sister were clinically diagnosed with renal hypoplasia, while their 36-year-old father presented with chronic kidney disease stage 3, focal segmental glomerulosclerosis, and optic disc pits. Genetic analysis identified a heterozygous PAX2 pathogenic variant c.685C>T, p.(Arg229*), in Family A and a heterozygous PAX2 pathogenic variant c.250G>A, p.(Gly84Ser) in Family B. Conclusions: The literature and our data further support that the same PAX2 variants may cause diverse kidney and ocular phenotypes among unrelated families and within the same family. Due to variable expressivity, a wide range of clinical manifestations of rare hereditary kidney diseases are still underdiagnosed, and a multidisciplinary approach is required to detect extrarenal signs of PAX2-related disorder. Full article

Wagner syndrome is a rare autosomal dominant vitreoretinopathy caused by mutations in chondroitin sulphate proteoglycan 2 (CSPG2)/Versican (VCAN). Here, we present a retrospective case series of a family pedigree with genetically confirmed Wagner syndrome (heterozygous VCAN exon 8 deletion), as follows: a 34-year-old mother (P1), 12-year-old daughter (P2), and a 2-year-old son (P3). The phenotype included early-onset cataract (P1), optically empty vitreous with avascular membranes (P1, 2), nasal dragging of optic nerve heads associated with foveal hypoplasia (P1, 2), tractional retinoschisis on optical coherence tomography (P2), and peripheral circumferential vitreo-retinal interface abnormality resembling white-without-pressure (P3) progressing to pigmented chorio-retinal atrophy (P1, 2). P2 developed a macula-off retinal detachment, which was treated initially with encircling band + vitrectomy + gas, followed by vitrectomy + heavy silicone oil tamponade for re-detachment from new inferior breaks. Strong vitreo-retinal adhesion was noted intraoperatively, which prevented the separation of posterior hyaloid beyond the equator. Electroretinograms from P1&2 demonstrated attenuated b-waves, a-waves, and flicker responses in light- and dark-adapted conditions, suggestive of generalised retinal dysfunction. Our patients demonstrated the clinical spectrum of Wagner syndrome, highlighting nasal dragging with foveal disruption as a distinguishing feature from other inherited vitreoretinopathies. Surgical outcomes demonstrate significant challenges in managing vitreo-retinal traction and need for further research into strategies to prevent sight loss. Full article

The proneural transcription factor atonal basic helix–loop–helix transcription factor 7 (ATOH7) is expressed in early progenitors in the developing neuroretina. In vertebrates, this is crucial for the development of retinal ganglion cells (RGCs), as mutant animals show an almost complete absence of RGCs, underdeveloped optic nerves, and aberrations in retinal vessel development. Human mutations are rare and result in autosomal recessive optic nerve hypoplasia (ONH) or severe vascular changes, diagnosed as autosomal recessive persistent hyperplasia of the primary vitreous (PHPVAR). To better understand the role of ATOH7 in neuroretinal development, we created ATOH7 knockout and eGFP-expressing ATOH7 reporter human induced pluripotent stem cells (hiPSCs), which were differentiated into early-stage retinal organoids. Target loci regulated by ATOH7 were identified by Cleavage Under Targets and Release Using Nuclease with sequencing (CUT&RUN-seq) and differential expression by RNA sequencing (RNA-seq) of wildtype and mutant organoid-derived reporter cells. Additionally, single-cell RNA sequencing (scRNA-seq) was performed on whole organoids to identify cell type-specific genes. Mutant organoids displayed substantial deficiency in axon sprouting, reduction in RGCs, and an increase in other cell types. We identified 469 differentially expressed target genes, with an overrepresentation of genes belonging to axon development/guidance and Notch signaling. Taken together, we consolidate the function of human ATOH7 in guiding progenitor competence by inducing RGC-specific genes while inhibiting other cell fates. Furthermore, we highlight candidate genes responsible for ATOH7-associated optic nerve and retinovascular anomalies, which sheds light to potential future therapy targets for related disorders. Full article

Congenital aniridia is a rare bilateral ocular malformation characterized by the partial or complete absence of the iris and is frequently associated with various anomalies, including keratopathy, cataract, glaucoma, and foveal and optic nerve hypoplasia. Additionally, nearly 50% of individuals with congenital aniridia experience symptoms of ocular dryness. Traditional treatment encompasses artificial tears and autologous serum. This study aimed to assess the effectiveness and safety of using platelet rich in growth factors (PRGF) plasma in patients with congenital aniridia and ocular dryness symptoms. Methods: The included patients underwent two cycles of a 3-month PRGF treatment. At 6 months, symptomatology was evaluated using the OSDI and SANDE questionnaires, and ocular surface parameters were analyzed. Results: The OSDI and SANDE values for frequency and severity demonstrated statistically significant improvements (p < 0.05). Ocular redness, corneal damage (corneal staining), and tear volume (Schirmer test) also exhibited statistically significant improvements (p < 0.05). No significant changes were observed in visual acuity or in the grade of meibomian gland loss. Conclusion: The use of PRGF in patients with congenital aniridia and ocular dryness symptoms led to significant improvements in symptomatology, ocular redness, and ocular damage. No adverse effects were observed during the use of PRGF. Full article

This study investigates a unique and complex eye phenotype characterized by minimal iris defects, foveal hypoplasia, optic nerve coloboma, and severe posterior segment damage. Through genetic analysis and bioinformatic tools, a specific nonsynonymous substitution, p.(Asn114Ser), within the PAX6 gene’s paired domain is identified. Although this substitution is not in direct contact with DNA, its predicted stabilizing effect on the protein structure challenges the traditional understanding of PAX6 mutations, suggesting a gain-of-function mechanism. Contrary to classical loss-of-function effects, this gain-of-function hypothesis aligns with research demonstrating PAX6’s dosage sensitivity. Gain-of-function mutations, though less common, can lead to diverse phenotypes distinct from aniridia. Our findings emphasize PAX6’s multifaceted influence on ocular phenotypes and the importance of genetic variations. We contribute a new perspective on PAX6 mutations by suggesting a potential gain-of-function mechanism and showcasing the complexities of ocular development. This study sheds light on the intricate interplay of the genetic alterations and regulatory mechanisms underlying complex eye phenotypes. Further research, validation, and collaboration are crucial to unravel the nuanced interactions shaping ocular health and development. Full article

The number of genes implicated in neurodevelopmental conditions is rapidly growing. Recently, variants in PPP2R1A have been associated with syndromic intellectual disability and a consistent, but still expanding, phenotype. The PPP2R1A gene encodes a protein subunit of the serine/threonine protein phosphatase 2A enzyme, which plays a critical role in cellular function. We report an individual showing pontocerebellar hypoplasia (PCH), microcephaly, optic and peripheral nerve abnormalities, and an absence of typical features like epilepsy and an abnormal corpus callosum. He bears an unreported variant in an atypical region of PPP2R1A. In silico studies, functional analysis using immunofluorescence, and super-resolution microscopy techniques were performed to investigate the pathogenicity of the variant. This analysis involved a comparative analysis of the patient’s fibroblasts with both healthy control cells and cells from an individual with the previously described phenotype. The results showed reduced expression of PPP2R1A and the presence of aberrant protein aggregates in the patient’s fibroblasts, supporting the pathogenicity of the variant. These findings suggest a potential association between PPP2R1A variants and PCH, expanding the clinical spectrum of PPP2R1A-related neurodevelopmental disorder. Further studies and descriptions of additional patients are needed to fully understand the genotype–phenotype correlation and the underlying mechanisms of this novel phenotype. Full article

PAX2 is a transcription factor expressed during embryogenesis in the eye, ear, CNS, and genitourinary tract, and is one of the major regulators of kidney development. Mutations in this gene are associated with papillorenal syndrome (PAPRS), a genetic condition characterized by optic nerve dysplasia and renal hypo/dysplasia. In the last 28 years, many cohort studies and case reports highlighted PAX2’s involvement in a large spectrum of kidney malformations and diseases, with or without eye abnormalities, defining the phenotypes associated with PAX2 variants as “PAX2-related disorders”. Here, we reported two new sequence variations and reviewed PAX2 mutations annotated on the Leiden Open Variation Database 3.0. DNA was extracted from the peripheral blood of 53 pediatric patients with congenital abnormalities of the kidney and urinary tract (CAKUT). PAX2 gene-coding exonic and flanking intronic regions were sequenced with Sanger technology. Two unrelated patients and two twins carrying one known and two unknown PAX2 variations were observed. The frequency of PAX2-related disorders in this cohort was 5.8%, considering all CAKUT phenotypes (16.7% in the PAPRS phenotype and 2.5% in non-syndromic CAKUT). Although PAX2 mutations have a higher frequency in patients with PAPRS or non-syndromic renal hypoplasia, from the review of variants reported to date in LOVD3, PAX2-related disorders are detected in pediatric patients with other CAKUT phenotypes. In our study, only one patient had a CAKUT without an ocular phenotype, but his twin had both renal and ocular involvement, confirming the extreme inter- and intrafamilial phenotypic variability. Full article

Septo-optic dysplasia (SOD) is a developmental phenotype characterized by midline neuroradiological anomalies, optic nerve hypoplasia, and pituitary anomalies, with a high degree of variability and additional systemic anomalies present in some cases. While disruption of several transcription factors has been identified in SOD cohorts, most cases lack a genetic diagnosis, with multifactorial risk factors being thought to play a role. Exome sequencing in a cohort of families with a clinical diagnosis of SOD identified a genetic diagnosis in 3/6 families, de novo variants in SOX2, SHH, and ARID1A, and explored variants of uncertain significance in the remaining three. The outcome of this study suggests that investigation for a genetic etiology is warranted in individuals with SOD, particularly in the presence of additional syndromic anomalies and when born to older, multigravida mothers. The identification of causative variants in SHH and ARID1A further expands the phenotypic spectra associated with these genes and reveals novel pathways to explore in septo-optic dysplasia. Full article

Congenital fibrosis of the extraocular muscles (CFEOM) is a congenital cranial dysinnervation disorder caused by developmental abnormalities affecting cranial nerves/nuclei innervating the extraocular muscles. Autosomal dominant CFEOM arises from heterozygous missense mutations of KIF21A or TUBB3. Although spatiotemporal expression studies have shown KIF21A and TUBB3 expression in developing retinal ganglion cells, it is unclear whether dysinnervation extends beyond the oculomotor system. We aimed to investigate whether dysinnervation extends to the visual system by performing high-resolution optical coherence tomography (OCT) scans characterizing retinal ganglion cells within the optic nerve head and retina. Sixteen patients with CFEOM were screened for mutations in KIF21A, TUBB3, and TUBB2B. Six patients had apparent optic nerve hypoplasia. OCT showed neuro-retinal rim loss. Disc diameter, rim width, rim area, and peripapillary nerve fiber layer thickness were significantly reduced in CFEOM patients compared to controls (p < 0.005). Situs inversus of retinal vessels was seen in five patients. Our study provides evidence of structural optic nerve and retinal changes in CFEOM. We show for the first time that there are widespread retinal changes beyond the retinal ganglion cells in patients with CFEOM. This study shows that the phenotype in CFEOM extends beyond the motor nerves. Full article

Dual-specificity tyrosine phosphorylation-regulated kinase 1A or DYRK1A, contributes to central nervous system development in a dose-sensitive manner. Triallelic DYRK1A is implicated in the neuropathology of Down syndrome, whereas haploinsufficiency causes the rare DYRK1A-related intellectual disability syndrome (also known as mental retardation 7). It is characterised by intellectual disability, autism spectrum disorder and microcephaly with a typical facial gestalt. Preclinical studies elucidate a role for DYRK1A in eye development and case studies have reported associated ocular pathology. In this study families of the DYRK1A Syndrome International Association were asked to self-report any co-existing ocular abnormalities. Twenty-six patients responded but only 14 had molecular confirmation of a DYRK1A pathogenic variant. A further nineteen patients from the UK Genomics England 100,000 Genomes Project were identified and combined with 112 patients reported in the literature for further analysis. Ninety out of 145 patients (62.1%) with heterozygous DYRK1A variants revealed ocular features, these ranged from optic nerve hypoplasia (13%, 12/90), refractive error (35.6%, 32/90) and strabismus (21.1%, 19/90). Patients with DYRK1A variants should be referred to ophthalmology as part of their management care pathway to prevent amblyopia in children and reduce visual comorbidity, which may further impact on learning, behaviour, and quality of life. Full article

Biallelic pathogenic variants in solute carrier family 38 member 8, SLC38A8, cause a pan-ocular autosomal recessive condition known as foveal hypoplasia 2, FVH2, characterised by foveal hypoplasia, nystagmus and optic nerve chiasmal misrouting. Patients are often clinically diagnosed with ocular albinism, but foveal hypoplasia can occur in several other ocular disorders. Here we describe nine patients from seven families who had molecularly confirmed biallelic recessive variants in SLC38A8 identified through whole genome sequencing or targeted gene panel testing. We identified four novel sequence variants (p.(Tyr88*), p.(Trp145*), p.(Glu233Gly) and c.632+1G>A). All patients presented with foveal hypoplasia, nystagmus and reduced visual acuity; however, one patient did not exhibit any signs of chiasmal misrouting, and three patients had features of anterior segment dysgenesis. We highlight these findings in the context of 30 other families reported to date. This study reinforces the importance of obtaining a molecular diagnosis in patients whose phenotype overlap with other inherited ocular conditions, in order to support genetic counselling, clinical prognosis and family planning. We expand the spectrum of SLC38A8 mutations which will be relevant for treatment through future genetic-based therapies. Full article

Congenital aniridia is a rare and severe panocular disease characterized by a complete or partial iris defect clinically detectable at birth. The most common form of aniridia occurring in around 90% of cases is caused by PAX6 haploinsufficiency. The phenotype includes ptosis, nystagmus, corneal limbal insufficiency, glaucoma, cataract, optic nerve, and foveal hypoplasia. Ataluren eye drops aim to restore ocular surface PAX6 haploinsufficiency in aniridia-related keratopathy (ARK). However, there are currently no available forms of the ophthalmic solution. The objective of this study was to assess the physicochemical and microbiological stability of ataluren 1% eye drop in preservative-free low-density polyethylene (LDPE) bottle with an innovative insert that maintains sterility after opening. Because ataluren is a strongly lipophilic compound, the formulation is complex and involves a strategy based on co-solvents in an aqueous phase or an oily formulation capable of totally dissolving the active ingredient. The visual aspect, ataluren quantification by a stability-indicating chromatographic method, and microbiological sterility were analyzed. The oily formulation in castor oil and DMSO (10%) better protects ataluren hydrolysis and oxidative degradation and permits its complete solubilization. Throughout the 60 days period, the oily solution in the LDPE bottle remained clear without any precipitation or color modification, and no drug loss and no microbial development were detected. The demonstrated physical and microbiological stability of ataluren 1% eye drop formulation at 22–25 °C might facilitate clinical research in aniridia. Full article

Congenital viral infections and the occurrence of septo-optic dysplasia, which is a combination of optic nerve hypoplasia, abnormal formation of structures along the midline of the brain, and pituitary hypofunction, support the biological plausibility of endocrine dysfunction in Zika-related microcephaly. In this case series we ascertained the presence and describe endocrine dysfunction in 30 children with severe Zika-related microcephaly from the MERG Pediatric Cohort, referred for endocrinological evaluation between February and August 2019. Of the 30 children, 97% had severe microcephaly. The average age at the endocrinological consultation was 41 months and 53% were female. The most frequently observed endocrine dysfunctions comprised short stature, hypothyroidism, obesity and variants early puberty. These dysfunctions occurred alone 57% or in combination 43%. We found optic nerve hypoplasia (6/21) and corpus callosum hypoplasia (20/21). Seizure crises were reported in 86% of the children. The most common—and clinically important—endocrine dysfunctions were pubertal dysfunctions, thyroid disease, growth impairment, and obesity. These dysfunctions require careful monitoring and signal the need for endocrinological evaluation in children with Zika-related microcephaly, in order to make early diagnoses and implement appropriate treatment when necessary. Full article