Trends over time in the incidence of congenital anophthalmia, microphthalmia and orbital malformation in England: database study

Construction and Identification of a Novel Mice Model of Microphthalmia

Purpose

Microphthalmia is a rare developmental eye disease that affects 1 in 7000 births. Currently, there is no cure for this condition. This study aimed to construct a stable mouse model of microphthalmia, thus providing a new tool for the study of the etiology of microphthalmia.

Methods

The Hedgehog signaling pathway plays a crucial role in eye development. One of the key mechanisms of the Sonic Hedgehog signaling is the strong transcriptional activation ability of GLI3, a major mediator of this pathway. This study used CRISPR/Cas9 system to construct a novel TgGli3Ki/Ki lens-specific over-expression mouse line. To identify the ocular characteristics of this line, quantitative PCR, Western blot, hematoxylin and eosin staining, immunofluorescent staining, and RNA-seq were performed on the ocular tissues of this line and normal mice.

Results

The TgGli3Ki/Ki lens-specific over-expression mouse model exhibits the ocular phenotype of microphthalmia. In the TgGli3Ki/Ki mouse, Gli3 is over-expressed in the lens, and the size of the eyeball and lens is significantly smaller than the normal one. RNA-seq analysis using the lens and the retina samples from TgGli3Ki/Ki and normal mice indicates that the phototransduction pathway is ectopically activated in the lens. Immunofluorescent staining of the lens samples confirmed this activation.

Conclusions

The TgGli3Ki/Ki mouse model consistently manifests the stereotypical microphthalmia phenotype across generations, making it an excellent tool for studying this severe eye disease.

Translational Relevance

This study developed a novel animal model to facilitate clinical research on microphthalmia.

Correlation Between the Computed Tomography and 3D Scanning System-Based Periorbital Morphology of Children with Congenital Microphthalmia

PURPOSE

This article aimed to explore the correlation between the periorbital morphology determined using a 3D scanning system and CT in congenital microphthalmia.

METHODS

Fifty-two children with microphthalmia aged 0-6 were enrolled in this study. All the participants were subjected to orbital CT scans and 3D scanning. The CT and 3D scanning images were separately processed to obtain the orbital and facial parameters. Multivariate regression was used to analyze the correlation between 3D parameters and orbital volume.

RESULTS

The orbital volume of the affected side (15.25 ± 3.35 cm3) was generally smaller than the unaffected side (18.58 ± 2.65 cm3, p < .001). Based on CT, at all ages, the parameters of the unaffected orbit were greater than the affected side. In the 3D scanning and 3D reconstruction based on CT, both unaffected and affected sides were highly correlated. A multiple linear regression equation including three 3D scanning factors was obtained for the orbital volume (R2 = 0.808, p < .001).

CONCLUSIONS

The retarded orbital volume could be estimated by the parameters based on 3D scanning, along with axial length. In the follow-up stage, 3D scanning can be a novel alternative method to assess the degree of orbital growth retardation in congenital microphthalmia.

The Repeatability and Reproducibility of a New Minimally Invasive Method for Orbital Pressure Measurement

BACKGROUND

Evaluation of orbital pressure is crucial for monitoring various orbital disorders. However, there is currently no reliable technique to accurately measure direct orbital pressure (DOP). This study aimed to establish a new method for the DOP as well as to verify its repeatability and reproducibility in rabbits.

METHODS

The study included 30 normal eyes from fifteen 3-month-old New Zealand white rabbits. After administering inhalation anesthesia, intraocular pressure (IOP) was determined by tonometry (Tonopen). For DOP manometry, a TSD104 pressure transducer was inserted between the disposable injection needle and the syringe, and the output results were displayed on a computer. Two observers independently participated in the experiment to verify its repeatability and reproducibility.

RESULTS

The mean IOP of rabbits was significantly higher than the DOP in normal rabbits (11.67 ± 1.08 mm Hg versus 4.91 ± 0.86 mm Hg, P < 0.001). No significant interocular difference was detected for both IOP and DOP ( P > 0.05). A high correlation was found for intraobserver measurements of both IOP (intraclass correlation coefficient = 0.87, P < 0.001) and DOP (intraclass correlation coefficient = 0.89, P < 0.001). A high agreement was also presented for the interobserver reproducibility for the measurements of IOP [Pearson correlation coefficient ( R ) = 0.86, P < 0.001] and DOP ( R = 0.87, P < 0.001). Direct orbital pressure was positively correlated with IOP in both observers ( R 1 = 0.66, R 2 = 0.62, P < 0.001). The Bland-Altman plots revealed that 5.0% (3/60) of the IOP and DOP measurement points were outside of the 95% limits of agreement, respectively.

CONCLUSIONS

The TSD104 pressure transducer-based manometry may serve as a reliable device for the measurement of DOP, providing real-time measuring results with acceptable reproducibility and repeatability.

Fertility and pregnancy in chronic myeloid leukemia: real-world experience from an Indian tertiary care institution

Chronic myeloid leukemia (CML) management during pregnancy is challenging. In this retrospective study, hospital records of CML patients treated between 2000 and 2021 were screened to identify patients who tried to conceive/got pregnant (planned and unplanned) on TKIs (tyrosine kinase inhibitors)/were pregnant at CML onset/fathered a child. We found ninety-three pregnancies involving thirty-three women and thirty-eight men, and they were analyzed for the pregnancy outcomes and the strategies utilized for CML management during pregnancy and the pre-conception period. There were two women and four men with primary infertility and five women with secondary infertility. TKIs were discontinued before conception in four planned pregnancies and at the time of recognition of pregnancy in unplanned pregnancies (n = 21). Unplanned pregnancy outcomes were two miscarriages, eight elective terminations, and eleven live births. Planned pregnancies led to four healthy babies. Outcomes of pregnancies at CML onset (n = 17) were six live births, one stillbirth, five elective terminations, and five abortions. Except for one child with congenital micro-ophthalmia, no other child born to the women on TKI had any malformations. Thirty-eight men fathered 51 healthy children. All but two patients (one planned and one unplanned pregnancy) lost their hematological responses during pregnancy and gained their previous best response after restarting TKI. In women who were pregnant at CML onset, complete cytological remission (CCYR) was achieved between 7 and 24 months (median:14 months) after starting TKI. During pregnancy, intermittent hydroxyurea ± TKI (in the second and third trimesters) was used to keep WBCs less than 30,000/mm3. Outcomes of pregnancies in CML patients can be optimized with our approach. TKIs (Imatinib and Nilotinib) can be safely used in the second and third trimesters. Delayed initiation or interruption of TKI during pregnancy does not negatively affect response to TKIs.

Validated establishment of anthropometric measurements of mid-face zone in Egyptian healthy preschool-age children: a cross-sectional study

Objectives

To provide normal reference data and identify growth patterns for craniofacial dimensions of a mid-face zone in healthy preschool Egyptian children.

Background

Anthropometry is the biological science that provides objective data to the craniofacial morphology evaluation, through a series of head and face measurements by using simple, noninvasive, low-risk, and inexpensive techniques.

Methods

The study was conducted on 3080 randomly selected healthy preschool boys and girls enrolled with criteria favoring good general health state and absence of any systemic disorders or long-term therapies. All children were subjected to detailed medical history, anthropometric measurements, head measurement (head circumference, head length, and width), and midface zone including eye measurements (inner canthal, outer canthal, inter-pupillary distance, and palpebral fissure length), nasal measurements (length, width, protrusion, columella length, and width), and ear measurements (length, width, projection, ear position, and rotation), with emphasis on the head should be erect (in the resting position) and both eyes facing forward.

Results

Upon plotting general measurements, head measurements, and specific measures of eye, nose, and ear on Z-score charts, it was shown that no significant difference was detected for the studied mid-face dimensions in both sexes with 0.6–1% low set ear setting which may be of a familial pattern. Egyptian facial morphology shows no similarities to Afro-Americans, but resembles those of Iranians with observed disagreeable ear features in comparison to Turkish children.

Conclusion

This study presents first referenced national Z-score curves that were accomplished to describe the growth pattern of mid-face proportions for Egyptian preschool healthy children.

Orbital Volume and Axial Length Development in Individuals Ages 12 to 60 Years With Congenital Microphthalmia: A Retrospective Cohort Study

OBJECTIVE

To analyze the stimulating effect of axial length development on orbital volume development in patients (ages 12-60 years) with congenital microphthalmia.

METHODS

This retrospective cohort study included 43 patients (86 eyes) with congenital microphthalmia. Three-dimensional images of the orbit were generated from past computed tomography scans, and digital orbital volume and axial length measurements were taken. The patients were divided into four age groups for analyses. Paired t tests and one-way analysis of variance tests were used to compare orbital volume and axial length between the affected and unaffected eyes. Pearson correlation analyses and scatter plots were used to investigate the correlations between age, orbital volume, and axial length in the affected and unaffected eyes. Linear regression analysis was used to determine the association between orbital volume and axial length.

RESULTS

The mean orbital volume in the affected and unaffected eyes was 17.08 ± 2.88 and 20.80 ± 2.55 cm3, respectively. The mean axis length in the affected and the unaffected groups was 12.73 ± 3.54 and 23.84 ± 1.43 mm, respectively. Significant differences were observed among orbital (t = 13.538, P < 0.001) volume and axial length (t = 21.339, P < 0.001) in the affected and the unaffected groups. There were no significant differences in affected orbital volume (F = 0.527, P > 0.05), unaffected orbital volume (F = 1.628, P > 0.05), affected axial length (F = 0.946, P > 0.05), and unaffected axial length (F = 2.217, P > 0.05) among the four age groups. According to the Pearson correlations, there were no significant correlations between age and affected volume, unaffected volume, affected axis, and unaffected axis (r = 0.095, 0.097, 0.084, and 0.022, respectively; all P > 0.05). Orbital volume was moderately correlated with axial length in the affected and unaffected groups (r = 0.470 and 0.410, respectively; both P < 0.01). Linear regression analysis revealed that a 1 mm change in axis length was associated with a 0.38 cm3 and 0.73 cm3 change in orbital volume in the affected and unaffected groups, respectively.

CONCLUSIONS

In individuals ages 12 to 60 years old with congenital microphthalmia, the effect of axis length on the orbital volume growth of the affected eye is only half that of the unaffected eye. The eyeball, orbital tissue, and craniofacial development all play an important role in the growth of orbital volume.

A Fetus with Congenital Microcephaly, Microphthalmia and Cataract Was Detected with Biallelic Variants in the OCLN Gene: A Case Report

Microcephaly and microphthalmia are both rare congenital abnormalities, while concurrently, these two are even rarer. The underlying etiology would be complex interplaying between heterogeneous genetic background and the environmental pathogens, particularly during critical periods of early tissue development. Here, we reported a prenatal case with microcephaly, microphthalmia, and bilateral cataracts detected by ultrasonography and confirmed by autopsy. Various routine infection-related tests and invasive genetic testing were negative. Whole genome sequencing of fetus and parents revealed OCLN gene defects may be associated with these multiple congenital abnormalities.

The Incoherent Fluctuation of Folate Pools and Differential Regulation of Folate Enzymes Prioritize Nucleotide Supply in the Zebrafish Model Displaying Folate Deficiency-Induced Microphthalmia and Visual Defects

Objective

Congenital eye diseases are multi-factorial and usually cannot be cured. Therefore, proper preventive strategy and understanding the pathomechanism underlying these diseases become important. Deficiency in folate, a water-soluble vitamin B, has been associated with microphthalmia, a congenital eye disease characterized by abnormally small and malformed eyes. However, the causal-link and the underlying mechanism between folate and microphthalmia remain incompletely understood.

Methods

We examined the eye size, optomotor response, intracellular folate distribution, and the expression of folate-requiring enzymes in zebrafish larvae displaying folate deficiency (FD) and ocular defects.

Results

FD caused microphthalmia and impeded visual ability in zebrafish larvae, which were rescued by folate and dNTP supplementation. Cell cycle analysis revealed cell accumulation at S-phase and sub-G1 phase. Decreased cell proliferation and increased apoptosis were found in FD larvae during embryogenesis in a developmental timing-specific manner. Lowered methylenetetrahydrofolate reductase (mthfr) expression and up-regulated methylenetetrahydrofolate dehydrogenase (NADP⁺-dependent)-1-like (mthfd1L) expression were found in FD larvae. Knocking-down mthfd1L expression worsened FD-induced ocular anomalies; whereas increasing mthfd1L expression provided a protective effect. 5-CH₃-THF is the most sensitive folate pool, whose levels were the most significantly reduced in response to FD; whereas 10-CHO-THF levels were less affected. 5-CHO-THF is the most effective folate adduct for rescuing FD-induced microphthalmia and defective visual ability.

Conclusion

FD impeded nucleotides formation, impaired cell proliferation and differentiation, caused apoptosis and interfered active vitamin A production, contributing to ocular defects. The developmental timing-specific and incoherent fluctuation among folate adducts and increased expression of mthfd1L in response to FD reflect the context-dependent regulation of folate-mediated one-carbon metabolism, endowing the larvae to prioritize the essential biochemical pathways for supporting the continuous growth in response to folate depletion.

The identification and validity of congenital malformation diagnoses in UK electronic health records: A systematic review

PURPOSE

To describe the methods used to identify and validate congenital malformation diagnoses recorded in UK electronic health records, and the results of validation studies.

METHODS

Medline and Embase were searched for publications between 1987 and 2019 that involved identifying congenital malformations from UK electronic health records using diagnostic codes. The methods and code-lists used to identify congenital malformations, and the methods and results of validations, were examined.

RESULTS

We retrieved 54 eligible studies; 36 identified congenital malformations from primary care data and 18 from secondary care data alone or in combination with birth and/or death records. Identification in secondary care data relied on codes from the 'Q' chapter for congenital malformations in ICD-10. In contrast, studies using primary care data frequently used additional codes outside of the 'P' chapter for congenital malformation diagnoses in Read, although the exact codes used were not always clear. Eight studies validated diagnoses identified in primary care data. The positive predictive value was highest (80%-100%) for congenital malformations overall, major malformations, and heart defects although the validity of the reference standard used was often uncertain. It was lowest for neural tube defects (71%) and developmental hip dysplasia (56%).

CONCLUSIONS

Studies identifying congenital malformations from primary care data provided limited details about the methods used. The few validation studies were limited to diagnoses recorded in primary care. Further assessments of all measures of validity in both data sources and of other malformation subgroups are needed, using robust reference standards and adhering to reporting guidelines.

Three-dimensional periorbital asymmetry assessment of congenital microphthalmia children with a structured light 3D scanning system

Congenital microphthalmia is a rare phenotype characterized by eye growth retardation. Due to the lack of eyeball stimulation, children suffering from congenital microphthalmia always have bony orbital maldevelopment, which leads to facial asymmetry. In the present study, a structured light 3D scanning system was used as a novel method to measure the three-dimensional periorbital asymmetry in children with congenital microphthalmia. Children with unilateral congenital microphthalmia of 0-6 years old were enrolled in the present study. All participants underwent an ultrasound scan to measure the axial length, and accepted the structured light 3D scanning system for their periorbital appearance. The degree of periorbital asymmetry was evaluated using 17 facial landmarks within a three-dimensional cartesian coordinate system (the X-axis represented the horizontal direction, the Y-axis represented the vertical direction, and the Z-axis represented the sagittal direction). Paired student t-test and ANOVA were used in the present study. A three-dimensional periorbital topography was also established to further illustrate the periorbital asymmetry. A total of 67 children were recruited, which included 31 boys and 34 girls. The axial length on the affected side (12.28 ± 3.35 mm) was generally smaller than that on the unaffected side (20.54 ± 1.65 mm, P < 0.001). When grouped by age, the periorbital asymmetry mainly manifested in the Y-axis and Z-axis directions. The unaffected side had a higher orbitale superior (5.09 ± 0.35 vs. 3.02 ± 0.30, P < 0.001) and a lower orbitale inferior (-19.52 ± 0.51 vs. -16.90 ± 0.53, P < 0.001) in 0-1 year old group. Same performances were also found in the 1-3 and 3-6 age groups. When grouped according to the proportion of axial length on the bilateral sides, seven of the 12 Y-values and all 12 Z-values had statistical differences. The structured Light 3D scanning system may serve as a beneficial complementary tool for computed tomography, in order to better understand the periorbital deformities caused by congenital microphthalmia.

Visual function and quality of life in children and adolescents with anophthalmia and microphthalmia treated with ocular prosthesis

PURPOSE

To evaluate health-related quality of life (HR-QoL), vision-related (VR-)QoL and perceptual visual dysfunction (PVD) among individuals with anophthalmia (A) and microphthalmia (M) treated with ocular prosthesis.

METHODS

The study comprised 15 individuals (mean age 6.6 years; range 1.7-14.1) with unilateral A or M. Three validated instruments measuring HR-QoL and VR-QoL were used: The Pediatric QoL Inventory (PedsQL), consisting of physical and psychosocial self-report and parent-proxy report (2-18 years); Children's Visual Function Questionnaire (CVFQ); and Effects of Youngsters' Eyesight on Quality of Life (EYE-Q). Perceptual visual dysfunctions (PVDs) were assessed by history taking according to a specific protocol.

RESULTS

A/M children and their parents showed low HR-QoL scores (PedsQL total score: 66.3; 69.6) compared with controls (83.0; 87.61) (p = 0.0035 and <0.0001, respectively, unpaired t-test). No differences were found between A/M children and parents, but parents tended to underestimate their children's emotional state. A/M children with subnormal visual acuity (VA) for age scored lower in physical health compared with A/M children with normal VA (p = 0.03, Mann-Whitney U-test). No significant VR-QoL differences between A/M children and references or between A/M children with subnormal or normal VA for age were found. More A/M children than controls exhibited PVDs in ≥1 area (7/11 versus 4/118; p < 0.0001, Fisher's exact test).

CONCLUSION

A/M individuals show poor HR-QoL and increased PVDs. No difference in QoL was found between children and parents, though the children tended to score lower in emotional well-being. A/M children with subnormal VA showed lower physical health score. These problems indicate the necessity of a thorough multidisciplinary assessment and follow-up of children with A/M.

The Use of Induced Pluripotent Stem Cells as a Model for Developmental Eye Disorders

Approximately one-third of childhood blindness is attributed to developmental eye disorders, of which 80% have a genetic cause. Eye morphogenesis is tightly regulated by a highly conserved network of transcription factors when disrupted by genetic mutations can result in severe ocular malformation. Human-induced pluripotent stem cells (hiPSCs) are an attractive tool to study early eye development as they are more physiologically relevant than animal models, can be patient-specific and their use does not elicit the ethical concerns associated with human embryonic stem cells. The generation of self-organizing hiPSC-derived optic cups is a major advancement to understanding mechanisms of ocular development and disease. Their development in vitro has been found to mirror that of the human eye and these early organoids have been used to effectively model microphthalmia caused by a VSX2 variant. hiPSC-derived optic cups, retina, and cornea organoids are powerful tools for future modeling of disease phenotypes and will enable a greater understanding of the pathophysiology of many other developmental eye disorders. These models will also provide an effective platform for identifying molecular therapeutic targets and for future clinical applications.

Mouse models for microphthalmia, anophthalmia and cataracts

Mouse mutants are a long-lasting, valuable tool to identify genes underlying eye diseases, because the absence of eyes, very small eyes and severely affected, cataractous eyes are easily to detect without major technical equipment. In mice, actually 145 genes or loci are known for anophthalmia, 269 for microphthalmia, and 180 for cataracts. Approximately, 25% of the loci are not yet characterized; however, some of the ancient lines are extinct and not available for future research. The phenotypes of the mutants represent a continuous spectrum either in anophthalmia and microphthalmia, or in microphthalmia and cataracts. On the other side, mouse models are still missing for some genes, which have been identified in human families to be causative for anophthalmia, microphthalmia, or cataracts. Finally, the mouse offers the possibility to genetically test the roles of modifiers and the role of SNPs; these aspects open new avenues for ophthalmogenetics in the mouse.

Prenatal diagnosis and implications of microphthalmia and anophthalmia with a review of current ultrasound guidelines: two case reports

BACKGROUND

Microphthalmia and anophthalmia are rare congenital fetal abnormalities. The combined incidence is estimated at 1 in 10,000 births. These two conditions arise from complex and incompletely understood genetic and/or environmental causes. Prenatal diagnosis is neither frequent nor easy and relies on precise, high-quality ultrasonography. Current antenatal ultrasound protocols for imaging of the fetal eye are inconsistent and inadequate to screen for the spectrum of ocular malformations, and there are no clear guidelines on detection of these rare abnormalities. Our study of two cases highlights the importance of early detection, and we review current practice and suggest a definitive fetal imaging protocol.

CASE PRESENTATION

We present two antenatal cases, one each of microphthalmia and anophthalmia, both diagnosed at the morphology scan at our tertiary fetal medicine unit. In both cases, the parents (a 36-year-old woman of Mauritanian ethnicity and a non-consanguineous partner of Nepalese descent, and a 31-year-old Caucasian woman and non-consanguineous Caucasian partner) elected to terminate their pregnancies and made unremarkable recoveries. Subsequent fetal autopsy confirmed the ultrasound scan findings.

CONCLUSIONS

We recommend that antenatal ultrasound guidelines are updated to specify use of a curvilinear transducer (2-9 MHz) to image both orbits in the axial and coronal planes, aided by use of a transvaginal probe when the transabdominal approach is inadequate to generate these images. When applicable, three-dimensional reverse-face imaging should be obtained to aid the diagnosis. The presence, absence, or non-visualization of lenses and hyaloid arteries should be documented in reports and these cases referred for a tertiary-level ultrasound scan and fetal medicine review. Imaging of the orbits should occur from 12 weeks' gestation. Magnetic resonance imaging and amniocentesis with chromosome microarray testing may provide additional genetic and structural information that may affect the overall morbidity associated with a diagnosis of microphthalmia or anophthalmia.