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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&gt, 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.

The aim of this study was to investigate the histopathological manifestations of congenital corneal staphyloma accompanied by anterior segment dysgenesis and evaluate the prognosis after penetrating keratoplasty with an ultralarge button graft. We retrospectively studied 8 pediatric patients with large congenital corneal staphylomas in the Department of Ophthalmology of Peking University Third Hospital, China, between September 2014 and December 2018. All patients underwent penetrating keratoplasty with ultralarge button grafts, as well as additional operations according to the abnormality of each eye. Pathological investigations of all samples obtained during penetrating keratoplasty were performed with hematoxylin and eosin staining. The main clinical characteristic of congenital corneal staphyloma was an extremely opaque and ectatic cornea. Histopathological examination showed abnormal corneal epithelia and stroma and an absence of Bowman membrane, Descemet membrane, and the endothelium. Different severities of anterior segment dysgenesis, presenting as various histopathological manifestations, were observed in all cases. Several postoperative complications occurred after penetrating keratoplasty in some of the patients; however, the complications were discovered and treated accordingly in a timely manner. Six patients achieved good visual outcomes and a satisfactory cosmetic appearance after penetrating keratoplasty. One patient eventually lost the transparency of the button because of corneal neovascularization, and 1 patient lost visual function because of retinal detachment. Congenital corneal staphyloma combined with anterior segment dysgenesis can exhibit various manifestations on histopathological examination. Penetrating keratoplasty with an ultralarge button graft seems to be a suitable treatment for congenital corneal staphyloma to obtain good functional and aesthetic prognoses.

Background Mutations in CRYAA, which encodes the α-crystallin protein, are associated with a spectrum of congenital cataract–microcornea syndromes. Results In this study, we performed clinical examination and subsequent genetic analysis in two unrelated sporadic cases of different geographical origins presenting with a complex phenotype of ocular malformation. Both cases manifested bilateral microphthalmia and severe anterior segment dysgenesis, primarily characterized by congenital aphakia, microcornea, and iris hypoplasia/aniridia. NGS-based analysis revealed two novel single nucleotide variants occurring de novo and affecting the translation termination codon of the CRYAA gene, c.520T > C and c.521A > C. Both variants are predicted to elongate the C-terminal protein domain by one-third of the original length. Conclusions Our report not only expands the mutational spectrum of CRYAA but also identifies the genetic cause of the unusual ocular phenotype described in this report.

Anterior segment dysgenesis (ASD) comprises a wide spectrum of developmental conditions affecting the cornea, iris, and lens, which may be associated with abnormalities of other organs. To identify disease-causing variants, we performed exome sequencing in 24 South Florida families with ASD. We identified 12 likely causative variants in 10 families (42%), including single nucleotide or small insertion&ndash, deletion variants in B3GLCT, BMP4, CYP1B1, FOXC1, FOXE3, GJA1, PXDN, and TP63, and a large copy number variant involving PAX6. Four variants were novel. Each variant was detected only in one family. Likely causative variants were detected in 1 out of 7 black and 9 out of 17 white families. In conclusion, exome sequencing for ASD allows us to identify a wide spectrum of rare DNA variants in South Florida. Further studies will explore missing variants, especially in the black communities.

Abnormal development of the ocular anterior segment may lead to a spectrum of clinical phenotypes ranging from primary congenital glaucoma (PCG) to variable anterior segment dysgenesis (ASD). The main objective of this study was to identify the genetic alterations underlying recessive congenital glaucoma with ASD (CG-ASD). Next-generation DNA sequencing identified rare biallelic CPAMD8 variants in four patients with CG-ASD and in one case with PCG. CPAMD8 is a gene of unknown function and recently associated with ASD. Bioinformatic and in vitro functional evaluation of the variants using quantitative reverse transcription PCR and minigene analysis supported a loss-of-function pathogenic mechanism. Optical and electron microscopy of the trabeculectomy specimen from one of the CG-ASD cases revealed an abnormal anterior chamber angle, with altered extracellular matrix, and apoptotic trabecular meshwork cells. The CPAMD8 protein was immunodetected in adult human ocular fluids and anterior segment tissues involved in glaucoma and ASD (i.e., aqueous humor, non-pigmented ciliary epithelium and iris muscles), as well as in periocular mesenchyme-like cells of zebrafish embryos. CRISPR/Cas9 disruption of this gene in F0 zebrafish embryos (96 hpf) resulted in varying degrees of gross developmental abnormalities, including microphthalmia, pharyngeal maldevelopment, and pericardial and periocular edemas. Optical and electron microscopy examination of these embryos showed iridocorneal angle hypoplasia (characterized by altered iris stroma cells, reduced anterior chamber, and collagen disorganized corneal stroma extracellular matrix), recapitulating some patients’ features. Our data support the notion that CPAMD8 loss-offunction underlies a spectrum of recessive CG-ASD phenotypes associated with extracellular matrix disorganization and provide new insights into the normal and disease roles of this gene.

Here, we report a patient with ring chromosome 6 [r(6)], associated with anterior segment dysgenesis (ASD) and other anomalies. The phenotype was due to a 1880 kb microdeletion at 6p25.3 identified by whole-genome array analysis, and was mainly attributable to a FOXC1 haploinsufficiency. Currently 37 patients with r(6) have been reported. We found that facial dysmorphism, ASD, heart anomalies, brain anomalies, and hearing loss are constant features only in severe cases of r(6), mainly related to hemizygosity of FOXC1. Thus, overlaps with other FOXC1 related phenotypes, such as the 6p25 deletion syndrome, Axenfeld-Rieger syndrome type 3, and ASD type 3. Contrarily, those patients whose r(6) does not disrupt FOXC1, have mild or moderate phenotypes and do not exhibit ASD. Fundação para a Ciência e a Tecnologia, Portugal, Research Grant, Grant/Award Number: HMSP‐ICT/0016/2013; CONACYT; Universidad de Guadalajara; PROINPEP info:eu-repo/semantics/publishedVersion

A 3-year-old girl presented with a history of watering, haze and increase in the size of the right eye for two months. The child had bilateral preauricular skin tags, limbal dermoid and dermolipoma, consistant with the diagnosis of Goldenhad syndrome. In addition, her right eye manifested enlarged cornea, flat anterior chamber, atrophic iris and elevated intraocular pressure. This case report highlights a possible association of anterior segment dysgenesis and glaucoma with Goldenhar syndrome.

A seven-month-old female domestic shorthaired cat was presented for buphthalmos in the right eye and corneal cloudiness in the left eye. Full ophthalmic examinations were performed for both eyes and enucleation was done for the right nonvisual eye. Congenital glaucoma caused by anterior segment dysgenesis was confirmed for the right eye. In the left eye, slit-lamp examination revealed focal corneal edema with several iris strands from iris collarette to the affected posterior corneal surfaces. Circular posterior corneal defect was suggested to be the cause of edema. Goniodysgenesis, additionally, was identified. Taken together, the diagnosis of Peters' anomaly which is a subtype of anterior segment dysgenesis was suggested in the left eye.

Development of the cornea, lens, ciliary body and iris within the anterior segment of the eye involves coordinated interaction between cells originating from the ciliary margin of the optic cup, the overlying periocular mesenchyme and the lens epithelium. Anterior segment dysgenesis (ASD) encompasses a spectrum of developmental syndromes that affect these anterior segment tissues. ASD conditions arise as a result of dominantly inherited genetic mutations and result in both ocular-specific and systemic forms of dysgenesis that are best exemplified by aniridia and Axenfeld–Rieger syndrome, respectively. Extensive clinical overlap in disease presentation amongst ASD syndromes creates challenges for correct diagnosis and classification. The use of animal models has therefore proved to be a robust approach for unravelling this complex genotypic and phenotypic heterogeneity. However, despite these successes, it is clear that additional genes that underlie several ASD syndromes remain unidentified. Here, we report the characterisation of a novel mouse model of ASD. Conditional deletion of Tsc1 during eye development leads to a premature upregulation of mTORC1 activity within the ciliary margin, periocular mesenchyme and lens epithelium. This aberrant mTORC1 signalling within the ciliary margin in particular leads to a reduction in the number of cells that express Pax6, Bmp4 and Msx1. Sustained mTORC1 signalling also induces a decrease in ciliary margin progenitor cell proliferation and a consequent failure of ciliary body and iris development in postnatal animals. Our study therefore identifies Tsc1 as a novel candidate ASD gene. Furthermore, the Tsc1-ablated mouse model also provides a valuable resource for future studies concerning the molecular mechanisms underlying ASD and acts as a platform for evaluating therapeutic approaches for the treatment of visual disorders., Summary: Conditional deletion of Tsc1 in the developing eye results in ciliary body and iris hypotrophy, demonstrating that aberrant mTORC1 signalling contributes to anterior segment dysgenesis (ASD).

Background : Developmental anomalies in congenital anomalies cause malformation, such as Anterior Segment Dysgenesis (ASD). Disorder in maturation of anterior segment of the eye occurs in ASD, associated with increased risk of glaucoma. This relation is not supported with enough data about characteristics pediatric patients with ASD in Indonesia. The aim of the study was to describe characteristics ASD in pediatric patient Cicendo Eye Hospital based on patients’ identity, clinical profile and obstetrics profile. Methods : This study used a descriptive method and conducted retrospectively. Data were collected from medical records of patient with ASD in Pediatric Ophthalmology and Strabismus Unit at Cicendo Eye Hospital, from January 2012 to December 2014. This study was conducted from July to November 2015. Total sampling based on inclusion criteria were used in this study. Statistic software was used to analyze data. Results : This study used a descriptive method and conducted retrospectively. Data were collected from medical records of patient with ASD in Pediatric Ophthalmology and Strabismus Unit at Cicendo Eye Hospital, from January 2012 to December 2014. This study was conducted from July to November 2015. Total sampling based on inclusion criteria were used in this study. Statistic software was used to analyze data. Conclusions : Characteristics pediatric patients with ASD at Cicendo Eye Hospital based on patients identity are mostly patients diagnosed in infant age group, from outside Bandung, and mostly boys. Based on clinical profile most diagnosis is congenital glaucoma, bilateral dominantly, and without complication. Based on obstetric profile most patients with ASD were born at term without difficulties. [AMJ.2016;3(4):616–70] DOI: 10.15850/amj.v3n4.948

Background Threonine Aspartase 1 (Taspase 1) is a highly conserved site‐specific protease whose substrates are broad‐acting nuclear transcription factors that govern diverse biological programs, such as organogenesis, oncogenesis, and tumor progression. To date, no single base pair mutations in Taspase 1 have been implicated in human disease. Methods A female infant with a new pattern of diagnostic abnormalities was identified, including severe craniofacial anomalies, anterior and posterior segment dysgenesis, immunodeficiency, and macrocytic anemia. Trio‐based whole exome sequencing was performed to identify disease‐causing variants. Results Whole exome sequencing revealed a normal female karyotype (46,XX) without increased regions of homozygosity. The proband was heterozygous for a de novo missense variant, c.1027G>A predicting p.(Val343Met), in the TASP1 gene (NM_017714.2). This variant has not been observed in population databases and is predicted to be deleterious. Conclusion One human patient has been reported previously with a large TASP1 deletion and substantial evidence exists regarding the role of several known Taspase 1 substrates in human craniofacial and hematopoietic disorders. Moreover, Taspase 1 deficiency in mice results in craniofacial, ophthalmological and structural brain defects. Taken together, there exists substantial evidence to conclude that the TASP1 variant, p.(Val343Met), is pathogenic in this patient.

International audience; Microphthalmia and anophthalmia (MA) are severe developmental eye anomalies, many of which are likely to have an underlying genetic cause. More than 30 genes have been described, each of which is responsible for a small percentage of these anomalies. Among these, is the FOXE3 gene, which was initially described in individuals with dominantly inherited anterior segment dysgenesis and, subsequently, associated with recessively inherited primary aphakia, sclerocornea and microphthalmia. In this work, we describe 8 individuals presenting with an MA phenotype. Among them, 7 are carrying biallelic recessive FOXE3 mutations and 2 of these have novel mutations: p.(Ala78Thr) and p.(Arg104Cys). The last of our patients is carrying in the heterozygous state the recessive p.(Arg90Leu) mutation in the FOXE3 gene. To further understand FOXE3 involvement in this wide spectrum of ocular anomalies with 2 different patterns of inheritance, we reviewed all individuals with ocular abnormalities described in the literature for which a FOXE3 mutation was identified. This review demonstrates that correlations exist between the mutation type, mode of inheritance and the phenotype severity. Furthermore, understanding the genetic basis of these conditions will contribute to overall understanding of eye development, improve the quality of care, genetic counseling and, in future, gene-based therapies.

Axenfeld-Rieger syndrome (ARS) is a disorder characterized by anterior segment dysgenesis, including abnormalities in the cornea, iris, and anterior chamber angle structures. It is occasionally associated with systemic developmental abnormalities, including craniofacial anomalies, dental abnormalities, cardiac valvular malformation, periumbilical redundant skin, and variable neurological and skeletal disorders. Patients with ARS have an approximately 50% risk of developing glaucoma, and this risk is higher in cases where the peripheral iris is highly inserted into the trabecular meshwork [1,2,3]. ARS is an autosomal dominant disorder with high penetration. It is primarily caused by a mutation of the pituitary homeobox 2 (PITX2) or forkhead box C1 (FOXC1) gene. Mutations in PITX2 on chromosome 4q25, or in FOXC1 at 6p25, have been identified in approximately 40% to 70% of patients with ARS [3,4]. These genes play an important role in the development of the anterior segment. FOXC1 is a member of the forkhead family of transcription factors, which have an evolutionarily conserved DNA-binding domain consisting of a 110-amino acid motif. It regulates embryogenesis through gene products that participate in the migration and differentiation of mesenchymal cells [5,6]. FOXC1 mutations include missense, frameshift, and nonsense mutations, as well as deletions and duplications. Among these, point mutations are the most common. Variable phenotypes result, with features of haploinsufficiency or gain-of-function mutations [5]. In this report, we describe the clinical characterization of a family with ARS in three generations and report the association of the genetic etiologic factors with ARS.

Rationale: Axenfeld–Rieger syndrome (ARS) is a rare autosomal dominant disorder with ocular anterior segment dysgenesis and systemic anomalies. Patient concerns: A 28-year-old Chinese Han female was referred to Beijing Tongren Eye Center for progressive decrease of the visual acuity on her right eye in the past month. Diagnoses: The patient was diagnosed as ARS with retinal detachment based on series of ophthalmic examinations performed. Interventions: A pars plana vitrectomy was performed to manage the retinal detachment. Outcomes: Her best-corrected visual acuity was slightly improved after surgery. Lessons: ARS is a developmental defect of ocular anterior segment with various clinical manifestations which might cause misdiagnosis.

Purpose To determine the ocular consequences of a dominant-negative mutation in the p85α subunit of phosphatidylinositol 3-kinase (PIK3R1) using a knock-in mouse model of SHORT syndrome, a syndrome associated with short stature, lipodystrophy, diabetes, and Rieger anomaly in humans. Methods We investigated knock-in mice heterozygous for the SHORT syndrome mutation changing arginine 649 to tryptophan in p85α (PIK3R1) using physical examination, optical coherence tomography (OCT), tonometry, and histopathologic sections from paraffin-embedded eyes, and compared the findings to similar investigations in two human subjects with SHORT syndrome heterozygous for the same mutation. Results While overall eye development was normal with clear cornea and lens, normal anterior chamber volume, normal intraocular pressure, and no changes in the retinal structure, OCT images of the knock-in mouse eyes revealed a significant decrease in thickness and width of the iris resulting in increased pupil area and irregularity of shape. Both human subjects had Rieger anomaly with similar defects including thin irides and irregular pupils, as well as a prominent ring of Schwalbe, goniosynechiae, early cataract formation, and glaucoma. Although the two subjects had had diabetes for more than 30 years, there were no signs of diabetic retinopathy. Conclusions A dominant-negative mutation in the p85α regulatory subunit of PI3K affects development of the iris, and contributes to changes consistent with anterior segment dysgenesis in both humans and mice.

Key Clinical Message In patients with foveal hypoplasia, anterior segment dysgenesis and an absence of systemic findings, consider a recently described syndrome of foveal hypoplasia, optic nerve decussation defects and anterior segment dysgenesis (FHONDA) in the differential diagnosis.

Anterior segment dysgenesis (ASD) encompasses a group of developmental disorders in which a closed angle phenotype in the anterior chamber of the eye can occur and 50% of patients develop glaucoma. Many ASDs are thought to involve an inappropriate patterning and migration of the periocular mesenchyme (POM), which is derived from cranial neural crest cells (NCCs) and mesoderm. Although, the mechanism of this disruption is not well understood, a number of transcriptional regulatory molecules have previously been implicated in ASDs. Here, we investigate the function of the transcription factor AP-2β, encoded by Tfap2b, which is expressed in NCCs and their derivatives. Wnt1-Cre-mediated conditional deletion of Tfap2b in NCCs resulted in post-natal ocular defects typified by opacity. Histological data revealed that the conditional AP-2β NCC knockout (KO) mutants exhibited dysgenesis of multiple structures in the anterior segment of the eye including defects in the corneal endothelium, corneal stroma, ciliary body and disruption in the iridocorneal angle with adherence of the iris to the cornea. We further show that this phenotype leads to a significant increase in intraocular pressure and a subsequent loss of retinal ganglion cells and optic nerve degeneration, features indicative of glaucoma. Overall, our findings demonstrate that AP-2β is required in the POM for normal development of the anterior segment of the eye and that the AP-2β NCC KO mice might serve as a new and exciting model of ASD and glaucoma that is fully penetrant and with early post-natal onset., Summary: Tissue-specific deletion of transcription factor AP-2β in the neural-crest-derived periocular mesenchyme generates a novel model of anterior segment dysgenesis and early onset glaucoma in mice.

Background Williams-Beuren syndrome is characterized by mild mental retardation, specific neurocognitive profile, hypercalcemia during infancy, distinctive facial features and cardiovascular diseases. We report on complete ophthalmologic, sonographic and genetic evaluation of a girl with a clinical phenotype of Williams-Beuren syndrome, associated with unilateral anterior segment dysgenesis and bilateral cleft of the soft and hard palate. These phenotypic features have not been linked to the haploinsufficiency of genes involved in the microdeletion. Case presentation A term born girl presented at the initial examination with clouding of the right cornea. On ultrasound biomicroscopy the anterior chamber structures were difficult to differentiate, showing severe adhesions from the opacified cornea to the iris with a kerato-irido-lenticular contact to the remnant lens, a finding consistent with Peters' anomaly. Genetic analyses including FISH confirmed a loss of the critical region 7q11.23, usually associated with the typical Williams-Beuren syndrome. Microsatellite analysis showed a loss of about 2.36 Mb. Conclusions A diagnosis of Williams-Beuren syndrome was made based on the microdeletion of 7q11.23. The unique features, including unilateral microphthalmia and anterior segment dysgenesis, were unlikely to be caused by the microdeletion. Arguments in favor of the latter are unilateral manifestation, as well as the fact that numerous patients with deletions of comparable or microscopically visible size have not shown similar manifestations.