A bird's eye view on the use of whole exome sequencing in rare congenital ophthalmic diseases.

Phenotypic and genotypic heterogeneity in congenital ocular diseases, especially in anterior segment dysgenesis (ASD), have created challenges for proper diagnosis and classification of diseases. Over the last decade, genomic research has indeed boosted our understanding in the molecular basis of ASD and genes associated with both autosomal dominant and recessive patterns of inheritance have been described with a wide range of expressivity. Here we describe the molecular characterization of a cohort of 162 patients displaying isolated or syndromic congenital ocular dysgenesis. Samples were analyzed with diverse techniques, such as direct sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing (WES), over 20 years. Our data reiterate the notion that PAX6 alterations are primarily associated with ASD, mostly aniridia, since the majority of the cohort (66.7%) has a pathogenic or likely pathogenic variant in the PAX6 locus. Unexpectedly, a high fraction of positive samples (20.3%) displayed deletions involving the 11p13 locus, either partially/totally involving PAX6 coding region or abolishing its critical regulatory region, underlying its significance. Most importantly, the use of WES has allowed us to both assess variants in known ASD genes (i.e., CYP1B1, ITPR1, MAB21L1, PXDN, and PITX2) and to identify rarer phenotypes (i.e., MIDAS, oculogastrointestinal-neurodevelopmental syndrome and Jacobsen syndrome). Our data clearly suggest that WES allows expanding the analytical portfolio of ocular dysgenesis, both isolated and syndromic, and that is pivotal for the differential diagnosis of those conditions in which there may be phenotypic overlaps and in general in ASD.

Up-Regulation of SorCS1, an Important Sorting Receptor, in the Retina of a Form-Deprivation Rat Model.

Visually guided regulation is a sophisticated and active process, whereby sensory input helps to shape ocular development. Here, we sought to investigate the potential involvement of SorCS1, an important protein in synaptic transmission in neuron, in retinal development. A form-deprivation (FD) rat model was established. Ocular variations induced by FD were examined, including changes to eye axial length and retinal thickness. Scotopic electroretinogram (ERG) was used to examine retinal function. RD-PCR assays were screened for differentially expressed genes in FD rat eyes. Immunofluorescence staining identified the expression pattern and localization of SorCS1 in rat retina, with or without FD treatment. Additionally, primary retinal neural cells were cultured and incubated with or without a light-dark cycle, and western blot and real-time PCR assays were used to examine the expression of SorCS1. Retinal neural cells were treated with recombinant SorCS1 (h-SorCS1) coated with beads in serum-free conditions to test for effects on cellular physiology and expression of neurotransmitters involved in visual development. To monitor cell viability, a CCK8 assay was employed. Our data demonstrated that FD led to ocular axial elongation and retinal thinning. ERG tests showed FD impaired electrophysiological function in rat. An age-related expression pattern of SorCS1 was observed in the rat retina, and SorCS1 was significantly up-regulated in the FD rat retina. In addition, in vitro evidence suggested a strong correlation between light exposure and SorCS1 expression. Furthermore, treatment of retinal neural cells with h-SorCS1-beads promoted cell viability, neurite outgrowth, and up-regulation of inhibitory neurotransmitter expression, which implies that over-expression of SorCS1 may cause abnormal retinal development. Our findings suggest that SorCS1 is involved in the physiological processes of light/visually guided ocular growth.

Clinicopathologic Features and Treatment Characteristics of Congenital Corneal Opacity Infants and Children Aged 3 Years or Less: A Retrospective Single Institution Analysis.

OBJECTIVE: In this retrospective single institution study, we investigated the clinicopathologic features and treatment characteristics of 90 patients with congenital corneal opacities (CCO) (117 eyes) who were 3 years and younger and treated at our hospital. SUBJECT AND METHODS: We reviewed the clinical data of patients with CCO who presented for the first time for treatment at our hospital between January 1, 2017, and December 31, 2017. CCO were classified using the "STUMPED" (Sclerocornea, Tears in Descement's membrane, Metabolic, Peters, Endothelial dystrophy and Dermoid) method and confirmed by pathological examination. -Results: Seventy percent of the patients had unilateral CCO. Iridocorneal adhesions (61 eyes, 52.1%) and cataracts (22 eyes, 18.8%) were the 2 most common ocular abnormalities. Systemic abnormalities were present in 5 patients (5.6%), including growth retardation (4 patients) and congenital brain defects (1 patient). Eighty-five eyes (72.6%) underwent penetrating keratoplasty (PK), and lamellar keratoplasty (LK) was performed in 30 (25.6%) eyes. Forty-seven (95.9%) eyes with Peters anomaly and all 16 eyes with sclerocornea received PK, and all 24 eyes with dermoids were treated with LK. CONCLUSION: Our study demonstrates that CCO has varied manifestations in infants and young children in China. A thorough medical history, careful clinical examination, and the use of accessory examinations such as ultrasound biomicroscopy are critical for the accurate diagnosis and classification of CCO and to provide guidance on therapeutic choices.

Associations between red reflex abnormality, consanguinity and intensive care hospitalization of newborns in Turkey.

BACKGROUND: Red reflex screening is the primary but unheeded test for the detection of vision- and life-threatening eye conditions. AIMS: To evaluate the red reflex of newborns, percentage of ocular diseases resulting in red reflex abnormality, and their relation with consanguinity in Southeast Turkey. METHODS: Newborns (n = 1358) were examined with pencil light and direct ophthalmoscopy. RESULTS: Eight hundred of these newborns were hospitalized in a rooming-in unit. (RIU) and 558 were in the neonatal intensive care service (NICS). In the RIU there were 7 (0.88%) newborns with abnormal red reflex and in the NICS there were 14 (2.51%). Sensitivity of pencil light examination was 71.4%. Studies from the Middle East have shown potential recessive genetic causes of common paediatric ocular conditions. In our study, consanguineous marriage was found to have a significant association with red reflex abnormality (P = 0.017). CONCLUSIONS: Red reflex screening test is important in the early diagnosis of vision- and life-threatening eye disorders in Southeast Turkey where consanguinity is common.

The refractive state of the eye in Icelandic horses with the Silver mutation.

BACKGROUND: The syndrome Multiple Congenital Ocular Anomalies (MCOA) is a congenital eye disorder in horses. Both the MCOA syndrome and the Silver coat colour in horses are caused by the same missense mutation in the premelanosome protein (PMEL) gene. Horses homozygous for the Silver mutation (TT) are affected by multiple ocular defects causing visual impairment or blindness. Horses heterozygous for the Silver mutation (CT) have less severe clinical signs, usually cysts arising from the ciliary body iris or retina temporally. It is still unknown if the vision is impaired in horses heterozygous for the Silver mutation. A recent study reported that Comtois horses carrying the Silver mutation had significantly deeper anterior chambers of the eye compared to wild-type horses. This could potentially cause refractive errors. The purpose of the present study was to investigate if Icelandic horses with the Silver mutation have refractive errors compared to wild-type horses. One hundred and fifty-two Icelandic horses were included in the study, 71 CT horses and five TT horses. All horses were genotyped for the missense mutation in PMEL. Each CT and TT horse was matched by a wild-type (CC) horse of the same age ± 1 year. Skiascopy and a brief ophthalmic examination were performed in all horses. Association between refraction and age, eye, genotype and sex was tested by linear mixed-effect model analysis. TT horses with controls were not included in the statistical analyses as they were too few. RESULTS: The interaction between age and genotype had a significant impact on the refractive state (P = 0.0001). CT horses older than 16 years were on average more myopic than wild-type horses of the same age. No difference in the refractive state could be observed between genotypes (CT and CC) in horses younger than 16 years. TT horses were myopic (-2 D or more) in one or both eyes regardless of age. CONCLUSION: Our results indicate that an elderly Icelandic horse (older than 16 years) carrying the Silver mutation is more likely to be myopic than a wild-type horse of the same age.

[Ultrasound Manifestations of Eyes of Pediatric Patients with Morning Glory Syndrome].

OBJECTIVE: To analyze ultrasonic manifestations of eyes of pediatric patients with morning glory syndrome (MGS). METHODS: Clinical data and ultrasound (US) findings for six children (4 males and 2 females, 5-60 months old) diagnosed with MGS between 2005 and 2016 were reviewed. RESULTS: Of the 12 eyes, seven were diagnosed with MGS; one with cataract; the other four were normal. One child had both eyes diagnosed with MGS. Of the seven eyes with MGS (5 right, 2 left), one was small associated with persistent hyperplastic primary vitreous (PHPV); 2 had retinal detachment. Findings of high frequency ultrasound included local anechoic lesions with distinct boundary showing a convert bottle-neck shape that appeared in the area of optic disk of posterior pole. The lesions communicated with the vitreous caicy and extended to the optic nerves. The lesions had a maximum depth of 4-15 mm [(8.29±4.42) mm] and a maximum width of 4-11 mm [(6.86±2.67) mm]. Hypoecho material was found in the bottom of five of the seven lesions. The distance between the end of the optic nerves and the bottom of the lesions ranged from 0 to 4.5 mm. Lower levels (Adler 0-1 grade) of blood flow in the bottom of the lesions were found compared with those (3-5 grade) in the rim of the lesions. CONCLUSION: MGS is rare and usual occurs in young children, especially infants. It is often associated with various eye complications. The ultrasound manifestations of MGS are characterized with a local anechoic lesion mimicking a convert bottle-neck shape in the area of optic disk of posterior pole.

Examination of the newborn: the key skills. Part 1. The eye.

Midwives are increasingly performing the examination of the newborn. In the first of a four-part series, this article considers the importance of the eye examination in the screening process. The significance of history taking, knowledge of risk factors and the detection of the red reflex will be explored. The necessity for early detection of retinoblastoma, congenital cataracts and glaucoma, and the prerequisite referral pathways that the Newborn infant physical examination (NIPE) requires will also be highlighted.

Ocular abnormalities in healthy Standardbred foals.

OBJECTIVE: To determine the prevalence and describe ocular abnormalities in healthy Standardbred foals within 48 h of birth. ANIMALS: One hundred and two neonatal foals. PROCEDURES: All foals had an unassisted delivery. On the basis of physical examination and the results of hematological and biochemical parameters, all foals were unaffected by systemic diseases. A complete ophthalmic examination was performed within 48 h of birth. Foals with ocular hemorrhages were re-examined weekly until the abnormalities were resolved. RESULTS: 65/102 (63.7%) foals did not show ocular abnormalities, while in 37/102 (36.3%) cases, ocular abnormalities were present. Retinal and subconjunctival hemorrhages were recorded in 19/102 (18.6%), and in 13/102 (12.7%), respectively. In 4/102 (3.9%) animals, an entropion of the lower eyelid was present. Only one foal (1%) showed a congenital nuclear unilateral cataract. No other ocular abnormalities were detected. However, all foals showed various degrees of remnants of hyaloid system. One week after the first ocular examination, retinal hemorrhages had resolved in 100% of the eyes, whereas subconjunctival hemorrhages had disappeared in all eyes by the second week following the first examination. CONCLUSIONS: The acquired ocular lesions observed with relatively high frequency in the examined healthy Standardbred foals were ocular hemorrhages, which always showed a good outcome. Although these abnormalities were present at birth, they were not considered strictly congenital but likely acquired during parturition. Instead, congenital ocular abnormalities were rarely diagnosed, and the entropion of the lower eyelid was the most common disease in the breed.

[An analysis of the pathophysiology of inherited diseases]. / Über die Klärung pathopysiologischer Ursachen genetisch bedingter Erkrankungen.

Evidence-based ophthalmology relies on a knowledge of the pathophysiological mechanisms at the molecular level. An example is the anti-VEGF therapy to treat the wet form of age-related macular degeneration. Its therapeutic effect is due to the neutralisation of a single type of molecule, the VEGF-A. The analysis of pathophysiological mechanisms of inherited diseases represents a unique opportunity to develop precise molecular therapeutic approaches. This analysis begins with the identification of the responsible gene which is followed by investigation of the function of its gene product along with the mutation-dependent changes using animal models and investigation of single molecules in expression systems. In this process the investigation of the pathomechanisms plays a central role. This review provides an orientation about studies on the pathophysiology of inherited diseases with a description of its methods and basic pathomechanisms. Furthermore, examples will be given on how the analysis of inherited retinal diseases has led to an understanding of the pathomechanisms of acquired diseases such as age-dependent macular degeneration and to the development of new therapeutic approaches.

A 24.2-Mb deletion of 4q12 --> q21.21 characterized by array CGH in a 131/2-year-old girl with short stature, mental retardation, developmental delay, hyperopia, exotropia, enamel defects, delayed tooth eruption and delayed puberty.

We report molecular and cytogenetic characterization of proximal deletion of chromosome 4q, del(4)(q12 --> q21.21) in a 131/2-year-old girl with short stature, mental retardation, developmental delay, hyperopia, exotropia, enamel defects, delayed tooth eruption and delayed puberty. We speculate that haploinsufficiency of the AMTN, ENAM and AMBN genes is most likely responsible for dental disorders, haploinsufficiency of the BMP2K genes is most likely responsible for ocular disorders, and haploinsufficiency of the EREG, AREG and BTC genes is most likely responsible for delayed puberty in this patient.

Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome in PMEL17 (Silver) mutant ponies: five cases.

OBJECTIVE: To describe the clinical phenotype and genetics of equine Multiple Congenital Ocular Anomalies (MCOA) syndrome in PMEL17 (Silver) mutant ponies. ANIMALS STUDIED: Five presumably unrelated ponies. PROCEDURES: The ponies were examined under field conditions in their barn by slit lamp biomicroscopy, indirect ophthalmoscopy, and applanation tonometry. Blood was collected and genomic DNA extracted for MCOA genotyping using the PMEL17ex11 marker. RESULTS: One pony solely presented with temporal ciliary body cysts, suggestive of the less severe Cyst phenotype of MCOA; the animal was heterozygous at the MCOA locus. Multiple bilateral anterior segment anomalies were identified in four ponies, consistent with the more severe MCOA phenotype characterized by cornea globosa, iris hypoplasia, encircling granula iridica along the pupillary ruff, and cataracts. These animals were homozygous for the mutant MCOA allele. Four of the ponies had a silver dapple or chocolate coat color with white or flaxen manes and tails. Silver dappling was masked by the palomino coloring of a 5th pony that was homozygous at the MCOA locus. CONCLUSIONS: The MCOA syndrome can be seen in ponies. The results of both clinical evaluation and genotyping resembled the previously described MCOA of both Rocky Mountain and Kentucky Mountain Saddle horses.

Congenital cystic eye: from prenatal diagnosis to therapeutic management and surgical treatment.

Only 28 cases of congenital cystic eye have been reported in the literature. The main issue in such cases is differential diagnosis between this malformation and different cystic malformations and masses of the orbital cavity and eyeball, the most common of which is microphthalmia with cyst. Both malformations arise from incomplete closure of the fetal optic vesicle in different stages of embryonic development. We present a case of congenital cystic eye, associated with coloboma and corneal dermoid of the fellow eye and with left brachiocephaly, discussing differential diagnosis with microphthalmia with cyst and illustrating the treatment we planned and performed. The patient first underwent a surgical excision of the left corneal dermoid, then a resection of the right orbital cyst. The last step was to perform a craniotomy and cranial vault remodeling. All the operations were planned and performed using a team approach. The team comprised an ophthalmologist, a plastic surgeon, and a neurosurgeon, and the result was a successful outcome.

Functional analysis of large MAF transcription factors and elucidation of their relationships with human diseases.

The large MAF transcription factor group is a group of transcription factors with an acidic region, a basic region, and a leucine zipper region. Four types of MAF, MAFA, MAFB, c-MAF, and NRL, have been identified in humans and mice. In order to elucidate the functions of the large MAF transcription factor group in vivo, our research group created genetically modified MAFA-, MAFB-, and c-MAF-deficient mice and analyzed their phenotypes. MAFA is expressed in pancreatic ß cells and is essential for insulin transcription and secretion. MAFB is essential for the development of pancreatic endocrine cells, formation of inner ears, podocyte function in the kidneys, and functional differentiation of macrophages. c-MAF is essential for lens formation and osteoblast differentiation. Furthermore, a single-base mutation in genes encoding the large MAF transcription factor group causes congenital renal disease, eye disease, bone disease, diabetes, and tumors in humans. This review describes the functions of large MAF transcription factors in vivo and their relationships with human diseases.

The red reflex examination in neonates: an efficient tool for early diagnosis of congenital ocular diseases.

BACKGROUND: The American Academy of Pediatrics recently published recommendations for the red reflex assessment in the newborn period to detect and treat ocular disorders as early as possible, and to prevent lifelong visual impairment and even save lives. The test is technically simple to perform, non-invasive, requires minimal equipment and can detect a variety of ocular pathologies including cataracts and retinal abnormalities. No specific national guidelines exist on this issue. OBJECTIVES: To document the implementation of red reflex examination in routine neonatal care and present the findings. METHODS: Our clinical experience following inclusion of the red reflex test into the newborn physical examination in a single center was reviewed. In addition, an electronic mail questionnaire was sent to all neonatology departments in Israel regarding performance of the red reflex test. RESULTS: During 2007-2008, five infants were identified with congenital cataracts at days 2-6 of life prior to discharge from hospital. Surgery was performed in one infant at age 2 months and all infants underwent a thorough follow-up. The incidence of congenital cataract in our center was 1:2300. Less than half the neonatology departments have endorsed the AAP recommendation and perform the red reflex test routinely. CONCLUSIONS: Abnormal red reflex test after delivery enables a rapid ophthalmologic diagnosis, intervention and close followup. We recommend that red reflex screening be performed as part of the newborn physical examination; if abnormal, an urgent ophthalmologic referral should be made.

Variability in Gene Expression is Associated with Incomplete Penetrance in Inherited Eye Disorders.

Inherited eye disorders (IED) are a heterogeneous group of Mendelian conditions that are associated with visual impairment. Although these disorders often exhibit incomplete penetrance and variable expressivity, the scale and mechanisms of these phenomena remain largely unknown. Here, we utilize publicly-available genomic and transcriptomic datasets to gain insights into variable penetrance in IED. Variants in a curated set of 340 IED-implicated genes were extracted from the Human Gene Mutation Database (HGMD) 2019.1 and cross-checked with the Genome Aggregation Database (gnomAD) 2.1 control-only dataset. Genes for which >1 variants were encountered in both HGMD and gnomAD were considered to be associated with variable penetrance (n = 56). Variability in gene expression levels was then estimated for the subset of these genes that was found to be adequately expressed in two relevant resources: the Genotype-Tissue Expression (GTEx) and Eye Genotype Expression (EyeGEx) datasets. We found that genes suspected to be associated with variable penetrance tended to have significantly more variability in gene expression levels in the general population (p = 0.0000015); this finding was consistent across tissue types. The results of this study point to the possible influence of cis and/or trans-acting elements on the expressivity of variants causing Mendelian disorders. They also highlight the potential utility of quantifying gene expression as part of the investigation of families showing evidence of variable penetrance.

Developmental eye disorders.

In developed countries, malformations of the eye are among the most common causes of serious visual impairment in newborns. The identification of pathogenic mutations in autosomal and X-linked transcription factors has advanced our understanding of the critical stages in human eye development and has begun to explain some unusual inheritance characteristics of these disorders. The functional characterisation of these genes in model organisms has prompted reinvestigation of affected individuals to identify previously unrecognized but consistent extra-ocular malformations. This dialogue between clinical genetics and basic developmental biology provides a paradigm to enhance our understanding of many critical developmental processes in human embryogenesis.

Cloning of breakpoints of a chromosome translocation identifies the AN2 locus.

Chromosome translocations involving 11p13 have been associated with familial aniridia in two kindreds highlighting the chromosomal localization of the AN2 locus. This locus is also part of the WAGR complex (Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation). In one kindred, the translocation is associated with a deletion, and probes for this region were used to identify and clone the breakpoints of the translocation in the second kindred. Comparison of phage restriction maps exclude the presence of any sizable deletion in this case. Sequences at the chromosome 11 breakpoint are conserved in multiple species, suggesting that the translocation falls within the AN2 gene.

[Congenital ocular melanocytosis and delayed psycho-intellectual development--a new association?]. / Melanocitoza oculara congenitala si intârziere in dezvolarea psihointelectuala--o alta asociere?

Congenital ocular melanocytosis (COM) is an extremely rare melanocytic hyperplasia (0.038% in Caucasian population); it affects episclera and sclera. The conjunctival epithelium is not affected, as opposed to conjunctival melanosis. The pigmentation is grayish-blue and its consistency with the underlying tissues as the conjunctiva moves (deep pigmentation) is an essential diagnostic clue. COM may be isolated or associated with facial pigmentation, in the area innervated by the trigeminal nerve--known as oculodermal melanocytosis or nevus of Ota. COM may associate the following findings: iris hypercromia, iris mammillations, fundus hypercromia, uveal melanoma (most frequent choroidal melanoma) and glaucoma (10%). Melanocytes have been found in the brain, orbit, bucal mucosa in COM.