Congenital Malformations of the Eye and Orbit

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.

[Embryonic development and congenital diseases of the orbit]

Many neuroradiologists focus primarily on the central nervous system and give little attention to other regions like the eye/orbit. It is easy to be deceived by the pitfall called satisfaction of search (also abbreviated SOS), despite most congenital eye diseases being easily recognized if one is aware of them. In this article, the most common congenital orbital abnormalities are described, and their basic prenatal causes are summarized.

Neuroimaging of Ocular Abnormalities in Children

In this article, we will discuss the essential MR imaging protocol required for the assessment of ocular abnormalities including malignancies. Then we will describe relevant anatomy, ocular embryogenesis, and genetics to establish a profound understanding of pathophysiology of the congenital ocular malformations. Finally, we will discuss pediatric ocular malignancies, benign mimics, and the most common congenital ocular malformations with case examples and illustrations and give tips on how to distinguish these entities on neuroimaging.

Surgical Outcomes After Frontalis Suspension Using Expanded Polytetrafluoroethylene Sling for Congenital Ptosis

Purpose The purpose of the study is to assess short- and long-term functional outcomes after frontalis suspension using expanded polytetrafluoroethylene (ePTFE) sling for congenital ptosis repair. Methods A retrospective, observational case review was conducted on pediatric patients who underwent frontalis suspension using ePTFE sling from 2008 to 2020. Functional success was assessed by lid height, lid symmetry, and parental satisfaction with the cosmetic outcome. Clinical course and long-term functional outcomes after surgery were assessed. Results Twenty-one cases met the inclusion criteria and were assessed. The follow-up time ranged from 13 months to 11 years (mean: six years). Functional success after one surgery was 62% at early and late postoperative periods. Six of 21 cases (29%) required revisional surgery in the early postoperative period due to undercorrection. Three cases (14%) were complicated by infection and/or granuloma formation. There were no cases of ptosis recurrence in the long term if success was seen in the early postoperative period. Conclusion ePTFE slings remain an excellent option for severe congenital ptosis repair with frontalis sling, demonstrating long-term functional success, with satisfactory lid symmetry and acceptable cosmetic outcome. This is of important consideration in patients younger than three years of age, where autogenous materials may not be recommended. The need for early revisional surgery for undercorrection is not uncommon. The current authors also demonstrate a low but considerable risk for infection and/or granuloma formation.

Clinical Characterization of Congenital Anophthalmic and Microphthalmic Cavities in Inidviduals With Craniofacial Anomalies

OBJECTIVE

Measure the frequency of anophthalmic and microphthalmic patients with craniofacial anomalies (FCAs).

DESIGN

Descriptive, cross-sectional, retrospective study.

SETTING

Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo (HRAC-USP). The medical records of patients treated at HRAC from 2000 to 2012 with a diagnosis of congenital anophthalmia or microphthalmia were examined. Patients were excluded for secondary anophthalmia, incomplete medical records, or information that could not be accessed.

OUTCOME MEASURES

Frequency of anophthalmia and microphthalmia; the proportions and diagnoses of associated FCAs; impairment of ocular appendages; extracranial or facial anomalies; genetic alterations; and surgical approach.

RESULTS

A total of 56 patients had anophthalmia (52.3%), 35 had microphthalmia (32.7%), and 16 patients had both (15%). Individuals with FCAs associated with microphthalmia, anophthalmia, or both totaled 74, corresponding to 69.2%. Anophthalmia was more likely than microphthalmia to be accompanied by FCAs, at 76.4% of patients ( P < 0.05). Cleft lip and palate were the main malformations associated with anophthalmia (23.64%), with microphthalmia (45%), and with both (44.44%). Reconstructive surgery was done in 63.6% of cases. The ocular attachments were compromised in 71% of cases. Extracraniofacial malformations were found in 9.3% of patients. Only 7 records contained karyotypes, and no changes directly related to anophthalmia or microphthalmia were found.

CONCLUSION

Anophthalmia is more frequent than microphthalmia and is more often accompanied by FCA. Cleft lip and cleft palate are the most frequent concomitant malformations.

Anterior Skull Base Abnormalities in Congenital Anosmia

INTRODUCTION

The structures of the skull and the brain are related to each other. Prior work in individuals with isolated congenital anosmia (ICA) showed that these individuals were characterized by olfactory bulb (OB) defects. The aim of this study was to compare the morphological pattern of the anterior skull base surrounding the OB between individuals with ICA and normosmic controls. We meant to investigate whether these features can help distinguish abnormalities from normal variation.

METHODS

We conducted a retrospective study to acquire T2-weighted magnetic resonance images from individuals diagnosed with ICA (n = 31) and healthy, normosmic controls matched for age and gender (n = 62). Between both groups, we compared the depth and width of the olfactory fossa, the angle of the ethmoidal fovea, as well as the angle of the lateral lamella of the cribriform plate. Within the ICA group, we further performed subgroup analyses based on the presence or absence of the OB, to investigate whether the morphology of the anterior skull base relates to the presence of OBs. The diagnostic performance of these parameters was evaluated using receiver operating characteristic analysis.

RESULTS

Individuals with ICA exhibited a flattened ethmoid roof and shallower olfactory fossa when compared to controls. Further, the absence of the OB was found to be associated with a higher degree of flattening of the ethmoid roof and a shallow olfactory fossa. We reached the results in the following areas under the receiver operating characteristic curves: 0.80 - angle of fovea ethmoidalis, 0.76 - depth of olfactory fossa, 0.70 - angle of lateral lamella of the cribriform plate for significant differentiation between individuals with ICA and normosmic controls.

CONCLUSION

Individuals with ICA exhibited an unusual anterior skull base surrounding the OB. This study supports the idea of an integrated development of OB and anterior skull base. Hence, the morphological pattern of the anterior skull base surrounding the OB helps distinguish individuals with ICA from normosmic controls and may therefore be useful for the diagnosis of ICA, although it is certainly not an invariable sign of congenital anosmia.

Dimensions of the optic chiasm: quantitative ultrasound comparison between fetuses with anophthalmia/microphthalmia and normal fetuses

Background

The precise pathogenesis of anophthalmia/microphthalmia remains unknown. Prenatal observation of the optic chiasm in fetuses with this malformation would assist in understanding the embryonic development of the condition. The present study aimed to establish the normal fetal size ranges of decussation of the optic chiasm, optic nerves, and optic tracts in the axial plane using two-dimensional transabdominal ultrasound throughout gestation and to compare these ranges to the corresponding values in fetuses with anophthalmia/microphthalmia.

Methods

In total, 310 normal fetuses and 16 fetuses with anophthalmia/microphthalmia were included in this study. The widths of the decussation of the optic chiasm, optic nerves, and optic tracts of normal fetuses at 19-40 weeks' gestation were measured in the axial plane by two-dimensional transabdominal ultrasound. The same widths were retrospectively measured in the axial plane using three-dimensional ultrasound in fetuses with anophthalmia/microphthalmia and compared to the results from the normal fetuses.

Results

The decussation, optic nerves, and optic tracts of 310 normal fetuses were measured. The normal widths of the decussation of the optic chiasm, optic nerves, and optic tracts increased linearly with gestational age. The interobserver and intraobserver reproducibility was excellent for the decussation but relatively low for the optic nerves and optic tracts. The optic nerve width of fetuses with anophthalmia/microphthalmia was significantly smaller than that of normal fetuses (P<0.001), but the widths of the decussation (P=0.061) and optic tracts (P=0.053) were not significantly different between the two groups.

Conclusions

The normal ranges of the decussation of the optic chiasm, optic nerves, and optic tracts established in this study can provide a quantitative basis for prenatal evaluation of the optic pathway. Fetal anophthalmia/microphthalmia may be associated with optic nerve hypoplasia.

Congenital Eyelid Anomalies: What General Physicians Need To Know

The eyelids are important structures that maintain the health of the ocular surface and have an important role in facial esthetics. Any interruption in eyelid development can lead to congenital eyelid deformities. Eyelid abnormalities in children may present at birth due to abnormal embryogenesis (congenital) or may occur at a later stage as the child matures (developmental). These abnormalities, in general, can be classified into three different categories depending on the location: malformation of the margins, malformation of the folds, and malformation of the position. Congenital and developmental eyelid abnormalities are among the most challenging problems encountered by ophthalmic reconstructive surgeons. Additional considerations include social factors regarding the patient’s self-awareness of their deformities and associated medical issues, which often coexist and maybe multisystem in nature. This article briefly reviews eyelid embryology, the most common congenital eyelid anomalies, and the management options available to address these conditions.

Spotlight on the pediatric eye: a pictorial review of orbital anatomy and congenital orbital pathologies

Orbital lesions in the pediatric population vary from adults in terms of their presentation, unique pathology, and imaging characteristics. The prompt and accurate diagnosis of these lesions is imperative to prevent serious consequences in terms of visual impairment and disfigurement. Along with dedicated ophthalmologic examination, imaging is instrumental in characterizing these lesions, both for accurate diagnosis and subsequent management. In our pictorial essay, we provide a basic review of orbital embryology, anatomy, and congenital orbital pathologies, with emphasis on radiological findings.

Ocular manifestations in Gorlin-Goltz syndrome

Background

Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients.

Results

Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients.

Conclusions

The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients.

MR Imaging of the Fetal Face: Comprehensive Review

The human face is a complex anatomic structure with an equally complex embryologic development. Derangement of the developmental process can result in various structural anomalies, which range from a mainly cosmetic deformity, such as cleft lip, to potentially life-threatening conditions such as arhinia. These anomalies (a) can occur as isolated anomalies; (b) can be associated with intracranial, spinal, or dental anomalies; or (c) can be a part of various syndromes, thus serving as diagnostic clues in such cases. Proper evaluation of fetal facial deformities can help in prognostication, family counseling, and prenatal or early postnatal intervention. Ultrasonography (US) is the first line of investigation in these cases. However, when US does not allow complete evaluation of these anomalies owing to its inherent limitations, magnetic resonance (MR) imaging allows comprehensive evaluation of the anomaly itself and also evaluation of various associations and the treatment approach. The embryology of the fetal facial structures is considered with regard to the MR imaging technique and the MR imaging anatomy. The MR imaging features of various structural anomalies are described and classified into six groups, namely, orofacial clefts, orbital anomalies, nasal anomalies, facial masses, external ear anomalies, and abnormal face shape or profile. Also, the key associations and relevant treatment implications are reviewed. The article provides a "one-stop shop" review of these unique disorders-from basic understanding of the embryology to applying the knowledge in clinical practice, helping the interprofessional team and the patients alike. ^©RSNA, 2018.

Orbital Hemangioma with Intracranial Vascular Anomalies and Hemangiomas: A New Presentation of PHACE Syndrome?

We present two cases of infants with a similar constellation of clinical findings: retro-orbital infantile hemangioma (IH), internal carotid artery (ICA) arteriopathy, and intracranial IH. In both cases, intracranial vascular anomalies and hemangiomas were found incidentally during evaluation of unilateral proptosis. Neither infant had evidence of cutaneous segmental IH of the face or neck, which might have provided a clue to the diagnosis of PHACE syndrome or of intracranial hemangiomas. In one case, intracranial involvement was particularly extensive and function threatening, with mass effect on the brain parenchyma. These cases serve to highlight the fact that clinical findings of proptosis, globe deviation, and strabismus should prompt immediate imaging to confirm the presence of orbital IHs and to exclude other diagnoses. Moreover, based on our cases and the embryologic origin of the orbit as a unique developmental unit, patients with confirmed retro-orbital IHs should undergo evaluation for anomalies associated with PHACE syndrome. Patients with orbital IHs and an additional major criterion for PHACE syndrome should be considered to have definite, and not just possible, PHACE syndrome.

Optic Nerve Aplasia: Case Report and Literature Review

Purpose:

To report three cases of optic nerve aplasia (ONA).

Case Report:

Herein three subjects with ONA are described, two subjects had unilateral involvement. In one of these cases, the fellow eye had an associated persistent hyperplastic primary vitreous (PHPV). The third patient had bilateral ONA with multiple intracranial anomalies. Previous reports are reviewed and reported findings are summarized. Orbital and brain magnetic resonance imaging (MRI) were normal in two of our cases and loss of corpus callosum in the third case. Narrow optic nerve was observed on the right side and normal appearance in other two patients.

Conclusion:

The diagnosis of optic nerve abnormalities in children requires a thorough ophthalmic examination and proper ancillary testing. Although MRI is valuable in the diagnosis of associated central nervous system anomalies, the optic nerve may appear in normal size and course on MRI images and thus one may not be able to diagnose ONA in eyes with opaque media.

The incidence, embryology, and oculofacial abnormalities associated with eyelid colobomas

PURPOSE

To describe a cohort of patients with congenital eyelid coloboma, to identify associated ocular and craniofacial abnormalities, and to establish any correlation between the size and location of eyelid colobomas and the presence of such abnormalities.

METHODS

An observational case series of 55 patients with eyelid coloboma treated by a single surgeon (JROC) between 1985 and 2005.

RESULTS

Eyelid colobomas predominantly affected the upper lids (93%), and were typically unilateral (76%). About a third (29%) were an isolated finding, with the remainder associated with other ocular (62%) and/or craniofacial (53%) abnormalities. Of those with ocular abnormalities; 19 (56%) had conjunctival traction bands, 16 (47%) choristomas, and 8 (24%) an abnormal globe. Of those with craniofacial abnormalities; 13 (45%) had Goldenhar Syndrome, 10 (35%) clefting disorders, and 4 (14%) Fraser Syndrome. Clefting disorders were typically associated with more severe colobomas and a higher incidence of conjunctival traction bands, first arch syndromes with smaller colobomas and more choristomas. Overall large colobomas were significantly associated with the presence of other craniofacial defects compared with small colobomas (P<0.01, χ(2)), but coloboma size did not correspond with the presence of other ocular abnormalities.

CONCLUSIONS

Coloboma size, location, and associations in this series are consistent with our current understanding of eyelid embryogenesis. It is likely that those colobomas associated with other craniofacial and ocular abnormalities are those which result from errors earlier in embryogenesis during eyelid specification, growth, and closure, whereas isolated colobomas arise later during eyelid separation, and after codependent structures have developed.

Spectrum of congenital defects of the eye and its adnexia in the pediatric age group; experience at a tertiary facility in Nigeria

The aim of this study was to investigate the types and presentation pattern of congenital defects of the eye and adnexia in our center. This is a retrospective review of congenital defects of the eye and adnexia over a 20-month period at a tertiary referral center in Lagos, Nigeria. Records were analyzed for age at presentation, laterality, gender, vision assessment, and type(s) of abnormality. Out of 412 pediatric patients, 40 (9.7 %) were seen to have congenital abnormality of the eye and/or its adnexia during the study period. There were 17 (42.5 %) males. Twelve patients (30.0 %) presented with involvement of the right eyes, nine (22.5 %) with left eyes, while 19 (47.5 %) had bilateral involvement. Twenty-eight patients (70.0 %) were aged 1 year or less at the time of presentation. A total of 69 entities were recognized as some children had two or more malformations. The common congenital defects identified were cataract (39.1 %), ptosis (17.4 %), glaucoma (8.7 %), and cornea opacity (7.2 %). Other less common congenital defects include: microphthalmos, anophthalmos, coloboma (lid and iris), dermoid cyst, and aniridia. All of the patients with available visual acuity documentation had visual impairment. A high proportion of the patients were lost to follow-up. Cataract, ptosis, and glaucoma were the commonest congenital defects of the eye and adnexia in our center and were associated with visual impairments. The significant loss of the patients during follow-up needs urgent investigation and attention to forestall this trend.

A child with leukocoria

Leukocoria, meaning "white pupil," describes the clinical finding of a white pupillary reflex on examination. It may be discovered through an asymmetric red reflex using direct ophthalmoscopy, or it may be seen incidentally on flash photography. It results from an abnormality of the eyeball that interferes with the normal reflective process. We report a case of a 3-year-old boy who presents with leukocoria found to be caused by a retinoblastoma and discuss the differential diagnosis of this uncommon presentation to the pediatric emergency department.

A broad range of ophthalmologic anomalies is part of the holoprosencephaly spectrum

Holoprosencephaly (HPE) is the most common disorder of the developing forebrain in humans, and is characterized by failed or incomplete cleavage of the cerebral hemispheres and deep brain structures. HPE includes wide phenotypic variability, with a continuum of both brain and craniofacial anomalies. While "classic" eye findings, including the spectrum of midline anomalies ranging from cyclopia to hypotelorism, as well as chorioretinal coloboma and microphthalmia, have been frequently described in patients with HPE, other subtle eye anomalies may also occur. In our study we prospectively analyzed a small cohort of 10 patients in whom we identified mutations in SHH, SIX3, ZIC2, or FGF8, the latter of which is a very recently described HPE-associated gene. We found that 9 of 10 patients had at least two ophthalmologic anomalies, including refractive errors, microcornea, microphthalmia, blepharoptosis, exotropia, and uveal coloboma. These findings contribute to the understanding of the phenotypic variability of the HPE spectrum, and highlight findings in one medically important but often incompletely investigated system.

Current techniques in surgical correction of congenital ptosis

Ptosis refers to vertical narrowing of the palpebral fissure secondary to drooping of the upper eyelid to a lower than normal position. Ptosis is considered congenital if present at birth or if it is diagnosed within the first year of life. Correction of congenital ptosis is one of the most difficult challenges ophthalmologists face. Multiple surgical procedures are available including, frontalis sling, levator advancement, Whitnall sling, frontalis muscle flap, and Mullerectomy. Selection of one technique over another depends on the consideration of several factors including the surgeon experience, the degree of ptosis in the patient, as well as the degree of levator muscle function. Current recommendations for the correction of congential ptosis vary based on clinical presentation. Advantages and disadvantages of each of these procedures are presented with recommendations to avoid complications.

Assessment of heritable genetic effects using new genetic tools and sentinels in an era of personalized medicine

The challenge of estimating human health effects from damage to the germ line may be met in the genomic era. Understanding the genetic, as opposed to postconception developmental basis of birth defects is critical to their use in monitoring heritable genetic damage. The causes of common birth defects are analyzed here: mendelian genetic, multigenic, developmental, inherited, or combinational. Only a small fraction of these (noninherited, mendelian genetic) are likely to be informative relative to germ cell mutagenesis, and these won't be discernible against the general background of birth defects. Targeted genetic testing as part of personalized medicine could be integrated into a strategy for assessing germ cell alterations in populations. Thus, "sentinel mutations," as originally proposed by Mulvihill and Ceizel, need not be restricted to X-linked or dominant mutations or conditions visible at birth. Several new sentinels related to personalized medicine are proposed, based on health impact (likelihood of monitoring), frequency, and genetic target suitability (responsiveness to diverse mutational mechanisms). Candidates could include CYP genes (related to metabolism of xenobiotics) important in optimizing drug doses and avoiding adverse reactions. High frequency LDLR mutations (related to familial high cholesterol) predict myocardial infarction in approximately50% of individuals. The more common recessive genetic diseases (cystic fibrosis, phenylketonuria, and others) monitored in newborn screening programs could be informative given parental analysis. New opportunities for genetic analyses need to be coupled with epidemiological studies on environmental exposures. These could focus on adverse outcomes related to tobacco, the mostubiquitous and potent environmental mutagen.

The difficult nosology of blepharophimosis-mental retardation syndromes: report on two siblings

Blepharophimosis-mental retardation syndromes (BMRS) include a group of clinically and etiologically heterogeneous conditions, which can occur as isolated features or as part of distinct disorders displaying multiple congenital anomalies. We report on two siblings, a 6-year-old girl and an 18-month-old male, presenting with overlapping clinical findings. Major characteristics included facial dysmorphisms with upward slanted palpebral fissures, blepharophimosis, telecanthus, hypertelorism, posteriorly rotated and abnormal ears, and micrognathia. Ectodermal abnormalities consisted of fine hair, sparse eyebrows, and thin skin. Both patients had feeding difficulties with gastro-esophageal reflux and growth retardation. Psychomotor skills were severely delayed with no verbal capacity. The male sib also displayed low growth hormone (GH) levels, while the older sister had low cholesterol and mildly elevated TSH levels. Numerous metabolic/genetic investigations, including cholesterol precursors, dosage, and high-resolution array-CGH, were negative. BMR syndromes, including Dubowitz syndrome, Marden-Walker syndrome, Ohdo/Ohdo-like syndromes, and the cholesterol storage disorders were considered. We concluded that these two patients are affected by a possible autosomal recessive condition within the heterogeneous clinical spectrum of BMRS, fitting with the Young-Simpson syndrome subtype.

Incidence, ocular findings, and systemic associations of ocular coloboma: a population-based study

OBJECTIVE

To describe the incidence, ocular findings, and systemic associations of coloboma in a population-based cohort of children.

METHODS

We retrospectively reviewed the medical records of pediatric (aged <19 years) patients diagnosed as having ocular coloboma from January 1, 1968, through December 31, 2007, as residents of Olmsted County, Minnesota.

RESULTS

Thirty-three children were newly diagnosed as having ocular coloboma (annual incidence, 2.4 per 100,000 residents <19 years old; prevalence, 1 in 2077 live births). Median patient age at diagnosis was 3.9 months (range, 2 days to 18.4 years), and 22 patients (67%) had unilateral involvement. Twelve patients (36%) had involvement of the anterior segment only, 13 (39%) of the posterior segment only, and 8 (24%) of both. During median ophthalmologic follow-up of 9.2 years (range, 13 days to 35.9 years), 19 patients (58%) had other ocular disorders, including amblyopia in 11 (33%) and strabismus in 10 (30%). During median medical follow-up of 16.8 years, 22 patients (67%) were diagnosed as having a nonocular disorder, including abnormal development in 12 (36%) and CHARGE (coloboma, heart defects, choanal atresia, retarded growth and development, genital abnormalities, and ear anomalies) syndrome in 4 (12%).

CONCLUSIONS

Ocular coloboma occurred in 1 in 2077 live births. More than half of the patients were diagnosed as having an ocular disorder other than coloboma, including strabismus and amblyopia in approximately one-third. Two-thirds of patients were diagnosed as having a nonocular disorder, including CHARGE syndrome in 1 in 8 patients.

Time-specific blockade of PDGFR with Imatinib (Glivec®) causes cataract and disruption of lens fiber cells in neonatal mice

This study aimed at investigating the response of lens epithelial cells in postnatal mice to Imatinib (Glivec®, a potent inhibitor of platelet-derived growth factor receptor (PDGFR)) treatment. Mouse eyes were sampled 10 days after administration of Imatinib (0.5 mg·g(-1)·day(-1)) for 3 days, at either 7, 14, or 21 days postpartum. Structural changes of lens were revealed by routine H.E. staining. Levels of proliferation and apoptosis were revealed by BrdU incorporation and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, respectively, and immunofluorescent staining with anti-PDGFRα antibody was carried out on the sections of eyeball. PDGFRα and p-PDGFRαprotein levels were evaluated by Western blot. Our results indicated that administration of Imatinib led to blockade of PDGFR signaling. Formation of cataracts was found only in those mice where treatment started from 7 days postpartum (P7), but was not observed in those samples from P14 nor P21. Fiber cells were disorganized in cataract lens core as observed histologically, and migration of epithelial cells was also inhibited. No apoptosis was detected with the TUNEL method. Our results indicated blockade of PDGFR at the neonatal stage (P7) would lead to cataracts and lens fiber cells disorganization, suggesting that PDGFR signaling plays a time-specific and crucial role in the postnatal development of lens in the mouse, and also may provide a new approach to produce a congenital cataract animal model.

Next generation sequencing in research and diagnostics of ocular birth defects

Sequence capture enrichment (SCE) strategies and massively parallel next generation sequencing (NGS) are expected to increase the rate of gene discovery for genetically heterogeneous hereditary diseases, but at present, there are very few examples of successful application of these technologic advances in translational research and clinical testing. Our study assessed whether array based target enrichment followed by re-sequencing on the Roche Genome Sequencer FLX (GS FLX) system could be used for novel mutation identification in more than 1000 exons representing 100 candidate genes for ocular birth defects, and as a control, whether these methods could detect two known mutations in the PAX2 gene. We assayed two samples with heterozygous sequence changes in PAX2 that were previously identified by conventional Sanger sequencing. These changes were a c.527G>C (S176T) substitution and a single basepair deletion c.77delG. The nucleotide substitution c.527G>C was easily identified by NGS. A deletion of one base in a long polyG stretch (c.77delG) was not registered initially by the GS Reference Mapper, but was detected in repeated analysis using two different software packages. Different approaches were evaluated for distinguishing false positives (sequencing errors) and benign polymorphisms from potentially pathogenic sequence changes that require further follow-up. Although improvements will be necessary in accuracy, speed, ease of data analysis and cost, our study confirms that NGS can be used in research and diagnostic settings to screen for mutations in hundreds of loci in genetically heterogeneous human diseases.

Identification of copy number variants associated with BPES-like phenotypes

Blepharophimosis-Ptosis-Epicanthus inversus syndrome (BPES) is a well-characterized rare syndrome that includes an eyelid malformation associated with (type I) or without premature ovarian failure (type II). Patients with typical BPES have four major characteristics: blepharophimosis, ptosis, epicanthus inversus and telecanthus. Mutations in the FOXL2 gene, encoding a forkhead transcription factor, are responsible for the majority of both types of BPES. However, many patients with BPES-like features, i.e., having at least two major characteristics of BPES, have an unidentified cause. Here, we report on a group of 27 patients with BPES-like features, but without an identified genetic defect in the FOXL2 gene or flanking region. These patients were analyzed with whole-genome high-density arrays in order to identify copy number variants (CNVs) that might explain the BPES-like phenotype. In nine out of 27 patients (33%) CNVs not previously described as polymorphisms were detected. Four of these patients displayed psychomotor retardation as an additional clinical characteristic. In conclusion, we demonstrate that BPES-like phenotypes are frequently caused by CNVs, and we emphasize the importance of whole-genome copy number screening to identify the underlying genetic causes of these phenotypes.

Unilateral optic nerve aplasia associated with rudimental retinal vasculature

Optic nerve aplasia (ONA) is a rare congenital malformation characterized by absence of optic disk, optic nerve, retinal ganglion cells, and central retina vessels. It is frequently associated with other ocular and central nervous system anomalies. In this paper, we describe a case of ONA associated with microphthalmos and a rudimental retinal vasculature in an otherwise healthy infant.

Blepharophimosis and mental retardation (BMR) phenotypes caused by chromosomal rearrangements: description in a boy with partial trisomy 10q and monosomy 4q and review of the literature

Blepharophimosis is a rare congenital anomaly of the palpebral fissure which is often associated with mental retardation and additional malformations. We report on a boy with blepharophimosis, ptosis and severe mental retardation carrying an unbalanced 4;10 translocation with terminal duplication of 10q [dup(10)(q25.1-->qter)] and monosomy of a small terminal segment of chromosome 4q [del(4)(34.3-->qter)]. Detailed clinical examination and review of the literature showed that the phenotype of the patient was mainly determined by the dup(10q). This paper reviews the chromosomal aberrations associated with BMR (blepharophimosis mental retardation) phenotypes. Searching different databases and reviewing the literature revealed 14 microscopically visible aberrations (among them UPD(14)pat) and two submicroscopic rearrangements causing blepharophimosis and mental retardation (BMR) syndrome. Some of these rearrangements-like the terminal dup(10q) identified in our patient or interstitial del(2q)-are associated with clearly defined phenotypes and can be well distinguished from each other on basis of clinical examination. This paper should assist clinicians and cytogeneticists when evaluating patients with BMR syndrome.