Visual impairment and ocular abnormalities in children with fetal alcohol syndrome

Fetal Brain-Derived Exosomal miRNAs from Maternal Blood: Potential Diagnostic Biomarkers for Fetal Alcohol Spectrum Disorders (FASDs)

Fetal alcohol spectrum disorders (FASDs) are leading causes of neurodevelopmental disability but cannot be diagnosed early in utero. Because several microRNAs (miRNAs) are implicated in other neurological and neurodevelopmental disorders, the effects of EtOH exposure on the expression of these miRNAs and their target genes and pathways were assessed. In women who drank alcohol (EtOH) during pregnancy and non-drinking controls, matched individually for fetal sex and gestational age, the levels of miRNAs in fetal brain-derived exosomes (FB-Es) isolated from the mothers' serum correlated well with the contents of the corresponding fetal brain tissues obtained after voluntary pregnancy termination. In six EtOH-exposed cases and six matched controls, the levels of fetal brain and maternal serum miRNAs were quantified on the array by qRT-PCR. In FB-Es from 10 EtOH-exposed cases and 10 controls, selected miRNAs were quantified by ddPCR. Protein levels were quantified by ELISA. There were significant EtOH-associated reductions in the expression of several miRNAs, including miR-9 and its downstream neuronal targets BDNF, REST, Synapsin, and Sonic hedgehog. In 20 paired cases, reductions in FB-E miR-9 levels correlated strongly with reductions in fetal eye diameter, a prominent feature of FASDs. Thus, FB-E miR-9 levels might serve as a biomarker to predict FASDs in at-risk fetuses.

Effects of In Utero EtOH Exposure on 18S Ribosomal RNA Processing: Contribution to Fetal Alcohol Spectrum Disorder

Fetal alcohol spectrum disorders (FASD) are leading causes of neurodevelopmental disability. The mechanisms by which alcohol (EtOH) disrupts fetal brain development are incompletely understood, as are the genetic factors that modify individual vulnerability. Because the phenotype abnormalities of FASD are so varied and widespread, we investigated whether fetal exposure to EtOH disrupts ribosome biogenesis and the processing of pre-ribosomal RNAs and ribosome assembly, by determining the effect of exposure to EtOH on the developmental expression of 18S rRNA and its cleaved forms, members of a novel class of short non-coding RNAs (srRNAs). In vitro neuronal cultures and fetal brains (11-22 weeks) were collected according to an IRB-approved protocol. Twenty EtOH-exposed brains from the first and second trimester were compared with ten unexposed controls matched for gestational age and fetal gender. Twenty fetal-brain-derived exosomes (FB-Es) were isolated from matching maternal blood. RNA was isolated using Qiagen RNA isolation kits. Fetal brain srRNA expression was quantified by ddPCR. srRNAs were expressed in the human brain and FB-Es during fetal development. EtOH exposure slightly decreased srRNA expression (1.1-fold; p = 0.03). Addition of srRNAs to in vitro neuronal cultures inhibited EtOH-induced caspase-3 activation (1.6-fold, p = 0.002) and increased cell survival (4.7%, p = 0.034). The addition of exogenous srRNAs reversed the EtOH-mediated downregulation of srRNAs (2-fold, p = 0.002). EtOH exposure suppressed expression of srRNAs in the developing brain, increased activity of caspase-3, and inhibited neuronal survival. Exogenous srRNAs reversed this effect, possibly by stabilizing endogenous srRNAs, or by increasing the association of cellular proteins with srRNAs, modifying gene transcription. Finally, the reduction in 18S rRNA levels correlated closely with the reduction in fetal eye diameter, an anatomical hallmark of FASD. The findings suggest a potential mechanism for EtOH-mediated neurotoxicity via alterations in 18S rRNA processing and the use of FB-Es for early diagnosis of FASD. Ribosome biogenesis may be a novel target to ameliorate FASD in utero or after birth. These findings are consistent with observations that gene-environment interactions contribute to FASD vulnerability.

Combined Single Gene Testing and Genome Sequencing as an Effective Diagnostic Approach for Anophthalmia and Microphthalmia Patients

Anophthalmia and microphthalmia (A/M) are among the most severe congenital developmental eye disorders. Despite the advancements in genome screening technologies, more than half of A/M patients do not receive a molecular diagnosis. We included seven consanguineous families affected with A/M from Pakistani cohort and an unknown molecular basis. Single gene testing of FOXE3 was performed, followed by genome sequencing for unsolved probands in order to establish a genetic diagnosis for these families. All seven families were provided with a genetic diagnosis. The identified variants were all homozygous, classified as (likely) pathogenic and present in an A/M-associated gene. Targeted FOXE3 sequencing revealed two previously reported pathogenic FOXE3 variants in four families. In the remaining families, genome sequencing revealed a known pathogenic PXDN variant, a novel 13bp deletion in VSX2, and one novel deep intronic splice variant in PXDN. An in vitro splice assay was performed for the PXDN splice variant which revealed a severe splicing defect. Our study confirmed the utility of genome sequencing as a diagnostic tool for A/M-affected individuals. Furthermore, the identification of a novel deep intronic pathogenic variant in PXDN highlights the role of non-coding variants in A/M-disorders and the value of genome sequencing for the identification of this type of variants.

Vision outcomes in children with fetal alcohol spectrum disorders

BACKGROUND

Previous studies demonstrated that children with Fetal Alcohol Spectrum Disorders (FASD) are more likely to have vision impairments. However, existing human clinical and epidemiological investigations are few and include limited sample sizes. This study aimed to explore the association between ophthalmologic abnormalities and FASD in a sample of 5-7 year old children in the general population.

METHODS

This was a cross-sectional study nested in a larger study intended to estimate the prevalence of FASD in San Diego, California, conducted between 2012 and 2014. Prenatal exposure to alcohol, dysmorphology examinations, and a neurobehavioral testing battery were collected for each child and an FASD diagnosis was assigned. Parents of participating children were asked to release their child's vision screening or diagnostic records.

RESULTS

Vision records were obtained for 424 participants in the larger prevalence study. Of these, 53 children were classified as having FASD. A statistically significant association was found between FASD and a diagnosis of strabismus; 5/42 (11.9%) of children who were classified as having FASD had strabismus compared to 6/290 (2.1%) of children who were not classified as having FASD (p = .01). All five cases of strabismus in the FASD group occurred in 19 children classified as having partial fetal alcohol syndrome (pFAS). No association was found between FASD and vision impairment (p = .23), refractive errors (p = .66), glasses/contact lens prescription (p = .30), or having one or more ophthalmological abnormalities (p = .97).

CONCLUSIONS

An association between strabismus and FASD, specifically partial FAS, suggests that the effect of alcohol exposure on risk of strabismus must be severe enough to result in facial features consistent with FASD. This emphasizes the importance of vision screening in children with FASD.

Molecular Markers in Maternal Blood Exosomes Allow Early Detection of Fetal Alcohol Spectrum Disorders

Prenatal alcohol exposure can cause developmental abnormalities (fetal alcohol spectrum disorders; FASD), including small eyes, face and brain, and neurobehavioral deficits. These cannot be detected early in pregnancy with available imaging techniques. Early diagnosis could facilitate development of therapeutic interventions. Banked human fetal brains and eyes at 9−22 weeks’ gestation were paired with maternal blood samples, analyzed for morphometry, protein, and RNA expression, and apoptotic signaling. Alcohol (EtOH)-exposed (maternal self-report) fetuses were compared with unexposed controls matched for fetal age, sex, and maternal race. Fetal brain-derived exosomes (FB-E) were isolated from maternal blood and analyzed for protein, RNA, and apoptotic markers. EtOH use by mothers, assessed by self-report, was associated with reduced fetal eye diameter, brain size, and markers of synaptogenesis. Brain caspase-3 activity was increased. The reduction in eye and brain sizes were highly correlated with amount of EtOH intake and caspase-3 activity. Levels of several biomarkers in FB-E, most strikingly myelin basic protein (MBP; r > 0.9), correlated highly with morphological abnormalities. Reduction in FB-E MBP levels was highly correlated with EtOH exposure (p < 1.0 × 10−10). Although the morphological features of FAS appear long before they can be detected by live imaging, FB-E in the mother’s blood may contain markers, particularly MBP, that predict FASD.

Fetal Alcohol Spectrum Disorder in a Newborn

Fetal alcohol spectrum disorder (FASD) can be suspected in newborns based on the maternal history of alcohol use during pregnancy and compelling physical attributes present at birth. The infrequency with which it is assessed during infancy makes FASD evaluation in newborns a formidable diagnostic challenge.

Our objective was to evaluate a three-day-old male infant born at 37 weeks gestation via vaginal delivery to a mother with admitted excessive alcohol intake for FASD. On physical appearance, the newborn had evidence of smooth philtrum and thin vermillion border, which are two of the three cardinal facial characteristics for dysmorphology. We propose that early detection is necessary to improve the management of neurodevelopmental concerns such as behavioral issues or heart and vision problems.

Inward rectifier potassium (Kir) channels in the retina: living our vision

Channel proteins are vital for conducting ions throughout the body and are especially relevant to retina physiology. Inward rectifier potassium (Kir) channels are a class of K+ channels responsible for maintaining membrane potential and extracellular K+ concentrations. Studies of the KCNJ gene (that encodes Kir protein) expression identified the presence of all of the subclasses (Kir 1-7) of Kir channels in the retina or retinal-pigmented epithelium (RPE). However, functional studies have established the involvement of the Kir4.1 homotetramer and Kir4.1/5.1 heterotetramer in Müller glial cells, Kir2.1 in bipolar cells, and Kir7.1 in the RPE cell physiology. Here, we propose the potential roles of Kir channels in the retina based on the physiological contributions to the brain, pancreatic, and cardiac tissue functions. There are several open questions regarding the expressed KCNJ genes in the retina and RPE. For example, why does not the Kir channel subtype gene expression correspond with protein expression? Catching up with multiomics or functional "omics" approaches might shed light on posttranscriptional changes that might influence Kir subunit mRNA translation within the retina that guides our vision.

Ethanol effects on cerebellar myelination in a postnatal mouse model of fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders (FASD) are alarmingly common, result in significant personal and societal loss, and there are no effective treatments for these disorders. Cerebellar neuropathology is common in FASD and can cause impaired cognitive and motor function. The current study evaluates the effects of ethanol on oligodendrocyte-lineage cells, as well as molecules that modulate oligodendrocyte differentiation and function in the cerebellum in a postnatal mouse model of FASD. Neonatal mice were treated with ethanol from P4-P9 (postnatal day), the cerebellum was isolated at P10, and mRNAs encoding oligodendrocyte-associated molecules were quantitated by qRT-PCR. Our studies demonstrated that ethanol significantly reduced the expression of markers for multiple stages of oligodendrocyte maturation, including oligodendrocyte precursor cells, pre-myelinating oligodendrocytes, and mature myelinating oligodendrocytes. Additionally, we determined that ethanol significantly decreased the expression of molecules that play critical roles in oligodendrocyte differentiation. Interestingly, we also observed that ethanol significantly reduced the expression of myelin-associated inhibitors, which may act as a compensatory mechanism to ethanol toxicity. Furthermore, we demonstrate that ethanol alters the expression of a variety of molecules important in oligodendrocyte function and myelination. Collectively, our studies increase our understanding of specific mechanisms by which ethanol modulates myelination in the developing cerebellum, and potentially identify novel targets for FASD therapy.

24-Epibrassinolide protects against ethanol-induced behavioural teratogenesis in zebrafish embryo

Embryonic studies have demonstrated the neurotoxic, teratogenic, and neurobehavioral toxicity of ethanol (EtOH). Although multiple mechanisms may contribute to these effects, oxidative stress has been described as the major damage pathway. In this regard, natural antioxidants have the potential to counteract oxidative stress-induced cellular damage. Therefore, the present study aimed to investigate the potential protective role of 24-epibrassinolide (24-EPI), a natural brassinosteroid with proved antioxidant properties, in EtOH-induced teratogenic effects during early zebrafish development. Embryos (~2 h post-fertilization - hpf) were exposed to 1 % EtOH, co-exposed to 24-EPI (0.01, 0.1 and 1 μM) and to 24-EPI alone (1 μM) for 24 h. Following exposure, biochemical evaluations were made at 26 hpf, developmental analysis was made throughout the embryo-larval period, and behavioural responses were evaluated at 120 hpf. Exposure to 1 % EtOH caused an increase in the number of malformations, which were diminished by 24-EPI. In addition, EtOH induced an accumulation of GSSG and consequent reduction of GSH:GSSG ratio, indicating the involvement of oxidative mechanisms in the EtOH-induced effects. These were reverted by 24-EPI as proved by the GSSG levels and GSH:GSSG ratio that returned to control values. Furthermore, exposure to EtOH resulted in behavioural deficits at 120 hpf as observed by the disrupted response to an aversive stimulus, suggesting the involvement of neurotoxic mechanisms. 24-EPI restored the behavioural deficits observed in a dose-dependent manner. The absence of effects in the embryos exposed solely to 24-EPI showed its safety during the exposure period. In conclusion, EtOH caused developmental teratogenicity and behavioural toxicity by inducing glutathione changes, which were prevented by 24-EPI.

Thinner retinal nerve fibre layer in young adults with foetal alcohol spectrum disorders

BACKGROUND/AIMS

Ophthalmological abnormalities such as ptosis, strabismus, refractive errors and optic nerve hypoplasia have been reported in foetal alcohol spectrum disorders (FASD). The purpose of this study was to investigate whether retinal thickness, retinal nerve fibre layer (RNFL) and optic disc area (ODA) differ between individuals with FASD and healthy controls.

METHODS

Best-corrected visual acuity (BCVA) in terms of logarithm of the minimum angle of resolution (logMAR), refraction, and fundus variables measured by optical coherence tomography were obtained from 26 young adults with FASD (12 women, median age 23 years) and 27 controls (18 women, median age 25 years).

RESULTS

The total thickness of the peripapillary RNFL was significantly lower in the FASD group than in controls; median (range) in the right/left eye was 96.5 (60-109)/96 (59-107) µm in the FASD group and 105 (95-117)/103 (91-120) µm among controls (p=0.001 and p=0.0001). Macular RNFL and retinal thickness measurements from the FASD group were also lower in most of the nine ETDRS areas, except for the central parts. Median (range) BCVA in the best eye was 0.00 (-0.1-0.3) logMAR in the FASD group and 0.00 (-0.2-0.0) logMAR in controls (p=0.001). No significant differences between the groups were found regarding ODA or refraction.

CONCLUSION

Significant differences in peripapillary and macular RNFL, retinal thickness and BCVA were found in this group of young adults with FASD compared with healthy controls. However, there were no differences in the size of the optic disc.

Ophthalmologic Findings in Fetal Alcohol Spectrum Disorders - A Cohort Study From Childhood to Adulthood

PURPOSE

To investigate whether ophthalmologic findings in children with fetal alcohol spectrum disorders (FASD) persist into young adulthood.

DESIGN

Prospective cohort study.

METHODS

Thirty children (13 female) adopted from eastern Europe to Sweden in the 1990s and diagnosed with FASD by a multidisciplinary team at the median age of 7.9 years were followed up by the same team 13-18 years later. Visual acuity (VA), refraction, stereoacuity, strabismus, ocular media, and fundus were investigated.

RESULTS

Median VA in right/left eye (OD/OS) was 20/32/20/32 (0.2/0.2 logMAR) in childhood and 20/22/20/20 (0.05/0.0 logMAR) in adulthood. Median (range) refraction OD/OS was +0.88/+1.25 (-8.75 to +4.75/-9.38 to +5.25) spherical equivalent diopter (D) in childhood and -0.25/-0.25 (-12 to +2.75/-13.25 to +2.63) in adulthood. Astigmatism (≥1 D) was the most common refractive error, in 13 (40%) and 14 (47%) subjects, respectively. Defective stereoacuity (>60 arc second) was noted in 20 subjects (67%) in childhood and 22 (73%) in adulthood. Heterotropia occurred in 12 subjects (40%) in childhood and 13 (43%) in adulthood. Increased tortuosity of the retinal vessels was found in 8 (27%) subjects in childhood vs 11 (37%) in adulthood. Optic nerve hypoplasia was recorded in 3 children and in 4 young adults.

CONCLUSIONS

Ophthalmologic findings such as refractive errors, strabismus, and fundus abnormalities are frequent in children with FASD and persist into early adulthood. The facial features characteristic of FAS diminish with age, making a dysmorphology evaluation in adulthood less reliable. An ophthalmologic examination is an important part of the evaluation of FASD in childhood as well as in young adulthood.

Evaluation of All Causes of Visual Function Loss in Children With Congenital Blepharoptosis

PURPOSE

To evaluate the overall frequency of visual function loss in pediatric patients with congenital blepharoptosis.

METHODS

This retrospective study was conducted in a tertiary center. The clinical records of patients younger than 18 years who were diagnosed as having congenital blephroptosis, underwent surgery, and had at least 1 year of postoperative follow-up were evaluated. Visual acuity results, presence of structural eye abnormalities, presence and type of amblyopia and strabismus, and refractive errors were recorded. The Mann-Whitney U test, chi-square test, and stepwise regression analysis were used for statistical analyses.

RESULTS

The mean final visual acuity was 0.11 ± 0.23 logarithm of the minimum angle of resolution (logMAR) (range: 0.0 to 1.0 logMAR) at the final follow-up visit for 143 eyes of 123 patients (65 male and 58 female). In this cohort, 30 patients (24.4%) had amblyopia and 5 patients (4.1%) had visual loss related to structural eye pathology, amounting to a total of 35 patients (28.5%) with visual function loss. The mean final visual acuities of patients without amblyopia, patients with amblyopia, and patients with organic eye disorders were 0.01 ± 0.03, 0.29 ± 0.28, and 0.55 ± 0.42 logMAR, respectively. Severe blepharoptosis (≥ 4 mm) was present in 25 patients (83.3%) with amblyopia. Deprivational amblyopia was detected in 25 of 36 eyes (69.4%) with amblyopia. Independent risk factors associated with final visual acuity were presence of amblyopia at presentation (correlation coefficient [ß] ± standard error [SE] = -0.29 ± 0.04; P < .001), anisometropia (ß ± SE = -0.27 ± 0.06; P < .001), and ptosis severity (ß ± SE = -0.09 ± 0.04; P = .012). Visual impairment (visual acuity < 20/40) persisted in 11.9% of eyes at the final follow-up.

CONCLUSIONS

Visual function loss was present in one-third of pediatric patients with congenital blepharoptosis. Both amblyopia and structural eye disorders contribute to visual impairment in this patient population. Structural eye pathology contributes independently to 4.1% of visual loss in this clinical setting. [J Pediatr Ophthalmol Strabismus. 2020;57(2):97-102.].

Genetics of anophthalmia and microphthalmia. Part 1: Non-syndromic anophthalmia/microphthalmia

Eye formation is the result of coordinated induction and differentiation processes during embryogenesis. Disruption of any one of these events has the potential to cause ocular growth and structural defects, such as anophthalmia and microphthalmia (A/M). A/M can be isolated or occur with systemic anomalies, when they may form part of a recognizable syndrome. Their etiology includes genetic and environmental factors; several hundred genes involved in ocular development have been identified in humans or animal models. In humans, around 30 genes have been repeatedly implicated in A/M families, although many other genes have been described in single cases or families, and some genetic syndromes include eye anomalies occasionally as part of a wider phenotype. As a result of this broad genetic heterogeneity, with one or two notable exceptions, each gene explains only a small percentage of cases. Given the overlapping phenotypes, these genes can be most efficiently tested on panels or by whole exome/genome sequencing for the purposes of molecular diagnosis. However, despite whole exome/genome testing more than half of patients currently remain without a molecular diagnosis. The proportion of undiagnosed cases is even higher in those individuals with unilateral or milder phenotypes. Furthermore, even when a strong gene candidate is available for a patient, issues of incomplete penetrance and germinal mosaicism make diagnosis and genetic counseling challenging. In this review, we present the main genes implicated in non-syndromic human A/M phenotypes and, for practical purposes, classify them according to the most frequent or predominant phenotype each is associated with. Our intention is that this will allow clinicians to rank and prioritize their molecular analyses and interpretations according to the phenotypes of their patients.

Optic Nerve Hypoplasia and Crouzon Syndrome

Crouzon syndrome is the most common cause of syndromic craniosynostosis. The authors present a previously unreported association between Crouzon syndrome and optic nerve hypoplasia. A male infant was transferred to the center for treatment of respiratory distress. He was diagnosed as having dysmorphic features, a membranous choanal stenossi bilaterally, and bilateral optic nerve hypoplasia. Genetic testing confirmed a molecular diagnosis of Crouzon syndrome. He had a complicated course in relation to choanal stenosis management, and was discharged home at 10 weeks of age. Although uncommon in Crouzon syndrome, the association with optic nerve hypoplasia changes the initial work-up and the management of parental expectations. [J Pediatr Ophthalmol Strabismus. 2018;55:e45-e48.].

The Early Developmental Outcomes of Prenatal Alcohol Exposure: A Review

Aim: This paper systematically reviews the literature on the effects of prenatal alcohol exposure on early child development from birth to 5 years with the aim to synthesize the developmental outcomes associated with prenatal alcohol exposure, and inform further research to improve our knowledge of the manifestations of prenatal alcohol exposure. Methods: Electronic databases (MEDLINE, Psych INFO, and Psych ARTICLES) were searched to find papers on the developmental outcomes of prenatal alcohol exposure in neonates, infants and toddlers and pre-school aged children. Studies were selected based on participants self-reporting alcohol consumption during pregnancy (either prospectively or retrospectively) and/or children being diagnosed with FASD based on a standardized assessment that includes a dysmorphology examination. The search was limited to peer-reviewed, English language studies involving human subjects, up to 5.5 years old. Results: Out of the 1,684 titles screened, a total of 71 papers were identified as relevant and included in this review. The majority of studies were prospective longitudinal studies. A range of assessment modalities (or tools) was used to determine neurodevelopmental outcomes of prenatal exposure to alcohol in the age group under review, the most frequently described being the Bayley Scales of Infant and Toddler Development (BSID) (n = 19). Studies varied in terms of the dose, frequency, and timing of alcohol consumption during pregnancy and methodology used to assess alcohol consumption. Findings demonstrate extensive evidence for poor global developmental outcomes in children prenatally exposed to alcohol, particularly with moderate to severe levels of prenatal alcohol exposure. Conclusion: The outcomes related to lower levels of prenatal alcohol exposure as well as outcomes in specific developmental domains, are poorly understood. Further research should aim to clarify the more subtle or less easily measurable manifestations of prenatal alcohol exposure on early development when the potential for greatest impact of interventions is highest.

Diving into the world of alcohol teratogenesis: a review of zebrafish models of fetal alcohol spectrum disorder

The term fetal alcohol spectrum disorder (FASD) refers to the entire suite of deleterious outcomes resulting from embryonic exposure to alcohol. Along with other reviews in this special issue, we provide insight into how animal models, specifically the zebrafish, have informed our understanding of FASD. We first provide a brief introduction to FASD. We discuss the zebrafish as a model organism and its strengths for alcohol research. We detail how zebrafish has been used to model some of the major defects present in FASD. These include behavioral defects, such as social behavior as well as learning and memory, and structural defects, disrupting organs such as the brain, sensory organs, heart, and craniofacial skeleton. We provide insights into how zebrafish research has aided in our understanding of the mechanisms of ethanol teratogenesis. We end by providing some relatively recent advances that zebrafish has provided in characterizing gene-ethanol interactions that may underlie FASD.

Developmental alcohol exposure impairs synaptic plasticity without overtly altering microglial function in mouse visual cortex

Fetal alcohol spectrum disorder (FASD), caused by gestational ethanol (EtOH) exposure, is one of the most common causes of non-heritable and life-long mental disability worldwide, with no standard treatment or therapy available. While EtOH exposure can alter the function of both neurons and glia, it is still unclear how EtOH influences brain development to cause deficits in sensory and cognitive processing later in life. Microglia play an important role in shaping synaptic function and plasticity during neural circuit development and have been shown to mount an acute immunological response to EtOH exposure in certain brain regions. Therefore, we hypothesized that microglial roles in the healthy brain could be permanently altered by early EtOH exposure leading to deficits in experience-dependent plasticity. We used a mouse model of human third trimester high binge EtOH exposure, administering EtOH twice daily by subcutaneous injections from postnatal day 4 through postnatal day 9 (P4-:P9). Using a monocular deprivation model to assess ocular dominance plasticity, we found an EtOH-induced deficit in this type of visually driven experience-dependent plasticity. However, using a combination of immunohistochemistry, confocal microscopy, and in vivo two-photon microscopy to assay microglial morphology and dynamics, as well as fluorescence activated cell sorting (FACS) and RNA-seq to examine the microglial transcriptome, we found no evidence of microglial dysfunction in early adolescence. We also found no evidence of microglial activation in visual cortex acutely after early ethanol exposure, possibly because we also did not observe EtOH-induced neuronal cell death in this brain region. We conclude that early EtOH exposure caused a deficit in experience-dependent synaptic plasticity in the visual cortex that was independent of changes in microglial phenotype or function. This demonstrates that neural plasticity can remain impaired by developmental ethanol exposure even in a brain region where microglia do not acutely assume nor maintain an activated phenotype.

Cleft Palate and Keratoconus in a Child Affected by Fetal Alcohol Syndrome: An Accidental Association?

This report describes the case of a 9-year-old girl affected by fetal alcohol syndrome who presented at birth with blepharophimosis and a cleft palate, which was submitted to surgery. She was referred to our hospital for a visual acuity reduction, where a diagnosis of keratoconus was made. This case highlights the rarity of the association between fetal alcohol syndrome and cleft palate and the previously unreported association involving fetal alcohol syndrome–keratoconus and cleft palate–keratoconus.

Updated Clinical Guidelines for Diagnosing Fetal Alcohol Spectrum Disorders

The adverse effects of prenatal alcohol exposure constitute a continuum of disabilities (fetal alcohol spectrum disorders [FASD]). In 1996, the Institute of Medicine established diagnostic categories delineating the spectrum but not specifying clinical criteria by which diagnoses could be assigned. In 2005, the authors published practical guidelines operationalizing the Institute of Medicine categories, allowing for standardization of FASD diagnoses in clinical settings. The purpose of the current report is to present updated diagnostic guidelines based on a thorough review of the literature and the authors' combined expertise based on the evaluation of >10 000 children for potential FASD in clinical settings and in epidemiologic studies in conjunction with National Institute on Alcohol Abuse and Alcoholism-funded studies, the Collaborative Initiative on Fetal Alcohol Spectrum Disorders, and the Collaboration on FASD Prevalence. The guidelines were formulated through conference calls and meetings held at National Institute on Alcohol Abuse and Alcoholism offices in Rockville, MD. Specific areas addressed include the following: precise definition of documented prenatal alcohol exposure; neurobehavioral criteria for diagnosis of fetal alcohol syndrome, partial fetal alcohol syndrome, and alcohol-related neurodevelopmental disorder; revised diagnostic criteria for alcohol-related birth defects; an updated comprehensive research dysmorphology scoring system; and a new lip/philtrum guide for the white population, incorporating a 45-degree view. The guidelines reflect consensus among a large and experienced cadre of FASD investigators in the fields of dysmorphology, epidemiology, neurology, psychology, developmental/behavioral pediatrics, and educational diagnostics. Their improved clarity and specificity will guide clinicians in accurate diagnosis of infants and children prenatally exposed to alcohol.

Visual-motor integration, visual perception, and fine motor coordination in a population of children with high levels of Fetal Alcohol Spectrum Disorder

BACKGROUND

Visual-motor integration (VMI) skills are essential for successful academic performance, but to date no studies have assessed these skills in a population-based cohort of Australian Aboriginal children who, like many children in other remote, disadvantaged communities, consistently underperform academically. Furthermore, many children in remote areas of Australia have prenatal alcohol exposure (PAE) and Fetal Alcohol Spectrum Disorder (FASD), which are often associated with VMI deficits.

METHODS

VMI, visual perception, and fine motor coordination were assessed using The Beery-Buktenica Developmental Test of Visual-Motor Integration, including its associated subtests of Visual Perception and Fine Motor Coordination, in a cohort of predominantly Australian Aboriginal children (7.5-9.6 years, n=108) in remote Western Australia to explore whether PAE adversely affected test performance. Cohort results were reported, and comparisons made between children i) without PAE; ii) with PAE (no FASD); and iii) FASD. The prevalence of moderate (≤16th percentile) and severe (≤2nd percentile) impairment was established.

RESULTS

Mean VMI scores were 'below average' (M=87.8±9.6), and visual perception scores were 'average' (M=97.6±12.5), with no differences between groups. Few children had severe VMI impairment (1.9%), but moderate impairment rates were high (47.2%). Children with FASD had significantly lower fine motor coordination scores and higher moderate impairment rates (M=87.9±12.5; 66.7%) than children without PAE (M=95.1±10.7; 23.3%) and PAE (no FASD) (M=96.1±10.9; 15.4%).

CONCLUSIONS

Aboriginal children living in remote Western Australia have poor VMI skills regardless of PAE or FASD. Children with FASD additionally had fine motor coordination problems. VMI and fine motor coordination should be assessed in children with PAE, and included in FASD diagnostic assessments.

Ocular Findings in Children With 22q11.2 Deletion Syndrome

PURPOSE

To identify the ocular features of children diagnosed as having 22q11.2 deletion syndrome in a Turkish population, which is the most common microdeletion syndrome with a wide range of facial and ocular abnormalities.

METHODS

Sixteen children aged between 4 months and 18 years with a microdeletion in chromosome 22q11.2 underwent a detailed ophthalmological examination including uncorrected and best corrected visual acuity testing, stereoscopic vision examination, biomicroscopic and indirect fundus examination, and ocular motility testing.

RESULTS

All patients had at least one ocular abnormality. The major abnormalities were eyelid abnormalities (eye hooding, narrow palpebral fissure, telecanthus, hypertelorism, sparse and thin eyebrows and eyelashes, blepharitis, and distichiasis), posterior embryotoxon, and tortuous retinal vessels in at least half of the patients. Other ophthalmological disorders were refractive errors, iris remnants, and strabismus.

CONCLUSIONS

The chromosome 22q11.2 deletion syndrome is associated with a wide range of ocular disorders, which necessitates a comprehensive eye examination for appropriate treatment and follow-up. Ocular findings sometimes can provide a clue to the diagnosis of 22q11.2 deletion. [J Pediatr Ophthalmol Strabismus. 2016;53(4):218-222].

Fetal Alcohol Spectrum Disorders: An Overview from the Glia Perspective

Alcohol consumption during pregnancy can produce a variety of central nervous system (CNS) abnormalities in the offspring resulting in a broad spectrum of cognitive and behavioral impairments that constitute the most severe and long-lasting effects observed in fetal alcohol spectrum disorders (FASD). Alcohol-induced abnormalities in glial cells have been suspected of contributing to the adverse effects of alcohol on the developing brain for several years, although much research still needs to be done to causally link the effects of alcohol on specific brain structures and behavior to alterations in glial cell development and function. Damage to radial glia due to prenatal alcohol exposure may underlie observations of abnormal neuronal and glial migration in humans with Fetal Alcohol Syndrome (FAS), as well as primate and rodent models of FAS. A reduction in cell number and altered development has been reported for several glial cell types in animal models of FAS. In utero alcohol exposure can cause microencephaly when alcohol exposure occurs during the brain growth spurt a period characterized by rapid astrocyte proliferation and maturation; since astrocytes are the most abundant cells in the brain, microenchephaly may be caused by reduced astrocyte proliferation or survival, as observed in in vitro and in vivo studies. Delayed oligodendrocyte development and increased oligodendrocyte precursor apoptosis has also been reported in experimental models of FASD, which may be linked to altered myelination/white matter integrity found in FASD children. Children with FAS exhibit hypoplasia of the corpus callosum and anterior commissure, two areas requiring guidance from glial cells and proper maturation of oligodendrocytes. Finally, developmental alcohol exposure disrupts microglial function and induces microglial apoptosis; given the role of microglia in synaptic pruning during brain development, the effects of alcohol on microglia may be involved in the abnormal brain plasticity reported in FASD. The consequences of prenatal alcohol exposure on glial cells, including radial glia and other transient glial structures present in the developing brain, astrocytes, oligodendrocytes and their precursors, and microglia contributes to abnormal neuronal development, reduced neuron survival and disrupted brain architecture and connectivity. This review highlights the CNS structural abnormalities caused by in utero alcohol exposure and outlines which abnormalities are likely mediated by alcohol effects on glial cell development and function.

Prenatal exposure to recreational drugs affects global motion perception in preschool children

Prenatal exposure to recreational drugs impairs motor and cognitive development; however it is currently unknown whether visual brain areas are affected. To address this question, we investigated the effect of prenatal drug exposure on global motion perception, a behavioural measure of processing within the dorsal extrastriate visual cortex that is thought to be particularly vulnerable to abnormal neurodevelopment. Global motion perception was measured in one hundred and forty-five 4.5-year-old children who had been exposed to different combinations of methamphetamine, alcohol, nicotine and marijuana prior to birth and 25 unexposed children. Self-reported drug use by the mothers was verified by meconium analysis. We found that global motion perception was impaired by prenatal exposure to alcohol and improved significantly by exposure to marijuana. Exposure to both drugs prenatally had no effect. Other visual functions such as habitual visual acuity and stereoacuity were not affected by drug exposure. Prenatal exposure to methamphetamine did not influence visual function. Our results demonstrate that prenatal drug exposure can influence a behavioural measure of visual development, but that the effects are dependent on the specific drugs used during pregnancy.

Fetal Alcohol Spectrum Disorders

Prenatal exposure to alcohol can damage the developing fetus and is the leading preventable cause of birth defects and intellectual and neurodevelopmental disabilities. In 1973, fetal alcohol syndrome was first described as a specific cluster of birth defects resulting from alcohol exposure in utero. Subsequently, research unequivocally revealed that prenatal alcohol exposure causes a broad range of adverse developmental effects. Fetal alcohol spectrum disorder (FASD) is the general term that encompasses the range of adverse effects associated with prenatal alcohol exposure. The diagnostic criteria for fetal alcohol syndrome are specific, and comprehensive efforts are ongoing to establish definitive criteria for diagnosing the other FASDs. A large and growing body of research has led to evidence-based FASD education of professionals and the public, broader prevention initiatives, and recommended treatment approaches based on the following premises:▪ Alcohol-related birth defects and developmental disabilities are completely preventable when pregnant women abstain from alcohol use.▪ Neurocognitive and behavioral problems resulting from prenatal alcohol exposure are lifelong.▪ Early recognition, diagnosis, and therapy for any condition along the FASD continuum can result in improved outcomes.▪ During pregnancy:◦no amount of alcohol intake should be considered safe;◦there is no safe trimester to drink alcohol;◦all forms of alcohol, such as beer, wine, and liquor, pose similar risk; and◦binge drinking poses dose-related risk to the developing fetus.

Aberrant development of post-movement beta rebound in adolescents and young adults with fetal alcohol spectrum disorders

Dependent on maternal (e.g. genetic, age) and exposure (frequency, quantity, and timing) variables, the effects of prenatal alcohol exposure on the developing fetus are known to vary widely, producing a broad range of morphological anomalies and neurocognitive deficits in offspring, referred to as fetal alcohol spectrum disorders (FASD). Maternal drinking during pregnancy remains a leading risk factor for the development of intellectual disabilities in the US. While few functional findings exist today that shed light on the mechanisms responsible for the observed impairments in individuals with FASD, animal models consistently report deleterious effects of early alcohol exposure on GABA-ergic inhibitory pathways. The post-motor beta rebound (PMBR), a transient increase of 15-30 Hz beta power in the motor cortex that follows the termination of movement, has been implicated as a neural signature of GABA-ergic inhibitory activity. Further, PMBR has been shown to be a reliable predictor of age in adolescents. The present study sought to investigate any differences in the development of PMBR between FASD and control groups. Beta event-related de-synchronization (ERD) and movement-related gamma synchronization (MRGS), although not clearly linked to brain maturation, were also examined. Twenty-two participants with FASD and 22 age and sex-matched controls (12-22 years old) underwent magnetoencephalography scans while performing an auditory oddball task, which required a button press in response to select target stimuli. The data surrounding the button presses were localized to the participants' motor cortices, and the time courses from the locations of the maximally evoked PMBR were subjected to wavelet analyses. The subsequent analysis of PMBR, ERD, and MRGS revealed a significant interaction between group and age in their effects on PMBR. While age had a significant effect on PMBR in the controls, no simple effects of age were detected in the FASD group. The FASD group additionally displayed decreased overall ERD levels. No group or age effects on MRGS were detected. The described findings provide further evidence for broad impairments in inhibitory processes in adolescents with FASD, possibly related to aberrant development of GABA-ergic pathways.

Impairment of social behaviour persists two years after embryonic alcohol exposure in zebrafish: A model of fetal alcohol spectrum disorders

Zebrafish naturally form social groups called shoals. Previously, we have shown that submerging zebrafish eggs into low concentrations of alcohol (0.00, 0.25, 0.50, 0.75 and 1.00 vol/vol% external bath concentration) during development (24h post-fertilization) for two hours resulted in impaired shoaling response in seven month old young adult zebrafish. Here we investigate whether this embryonic alcohol exposure induced behavioural deficit persists to older age. Zebrafish embryos were exposed either to fresh system water (control) or to 1% alcohol for two hours, 24h after fertilization, and were raised in a high-density tank system. Social behaviour was tested by presenting the experimental fish with a computer animated group of zebrafish images, while automated tracking software measured their behaviour. Control fish were found to respond strongly to animated conspecific images by reducing their distanceand remaining close to the images during image presentation, embryonic alcohol treated fish did not. Our results suggest that the impaired shoaling response of the alcohol exposed fish was not due to altered motor function or visual perception, but likely to a central nervous system alteration affecting social behaviour itself. We found the effects of embryonic alcohol exposure on social behaviour not to diminish with age, a result that demonstrates the deleterious and potentially life-long consequences of exposure to even small amount of alcohol during embryonic development in vertebrates.

Use of novel inhalation kinetic studies to refine physiologically-based pharmacokinetic models for ethanol in non-pregnant and pregnant rats

Ethanol (EtOH) exposure induces a variety of concentration-dependent neurological and developmental effects in the rat. Physiologically-based pharmacokinetic (PBPK) models have been used to predict the inhalation exposure concentrations necessary to produce blood EtOH concentrations (BEC) in the range associated with these effects. Previous laboratory reports often lacked sufficient detail to adequately simulate reported exposure scenarios associated with BECs in this range, or lacked data on the time-course of EtOH in target tissues (e.g. brain, liver, eye, fetus). To address these data gaps, inhalation studies were performed at 5000, 10 000, and 21 000 ppm (6 h/d) in non-pregnant female Long-Evans (LE) rats and at 21 000 ppm (6.33 h/d) for 12 d of gestation in pregnant LE rats to evaluate our previously published PBPK models at toxicologically-relevant blood and tissue concentrations. Additionally, nose-only and whole-body plethysmography studies were conducted to refine model descriptions of respiration and uptake within the respiratory tract. The resulting time-course and plethysmography data from these in vivo studies were compared to simulations from our previously published models, after which the models were recalibrated to improve descriptions of tissue dosimetry by accounting for dose-dependencies in pharmacokinetic behavior. Simulations using the recalibrated models reproduced these data from non-pregnant, pregnant, and fetal rats to within a factor of 2 or better across datasets, resulting in a suite of model structures suitable for simulation of a broad range of EtOH exposure scenarios.

Optic nerve hypoplasia in children and adolescents; prevalence, ocular characteristics and behavioural problems

PURPOSE

To report prevalence, ocular characteristics and coexisting behavioural problems in children and adolescents with optic nerve hypoplasia (ONH), which is a common cause of visual impairment in children in western countries, often associated with neurological or endocrinological problems and where autism has been reported in severe cases with blindness.

METHODS

This is a population-based cross-sectional study of patients <20 years of age who had been diagnosed with ONH and lived in the county of Stockholm in December 2009. Ophthalmological assessments including fundus photographs with optic disc analyses were made. A questionnaire was used to screen for behaviour and development.

RESULTS

The prevalence of ONH in all living children <18 years of age in Stockholm was 17.3/100 000 with a prevalence of visual impairment (<0.3) of 3.9/100 000. In total, 66 patients, median age 9.3 years (0.6-19.4), 36 with bilateral and 30 with unilateral ONH, were included in the current study; 53 were re-examined clinically, group A, and 13 agreed to retrospective analyses of existing medical records, group B. Analyses of the optic discs were made in fundus photographs from 53 patients comparing a semi-automated (Retinal Size Tool) and a manual method (Zeki). There was a strong curvilinear correlation (r(S)  = -0.91 p < 0.0001 for both eyes). Behavioural problems were more common (p < 0.05) in bilateral ONH.

CONCLUSION

Optic nerve hypoplasia is a common ocular malformation with a prevalence of 17.3/100 000 children and adolescents <18 years of age in Stockholm. Unilateral ONH seems as common as bilateral.

Effects of one- and three-day binge alcohol exposure in neonatal C57BL/6 mice on spatial learning and memory in adolescence and adulthood

Binge-like alcohol exposure during the early postnatal period in rats and mice causes deficits in spatial learning and memory that persist into adulthood. Wozniak et al. (2004) reported that heavy binge alcohol exposure on postnatal day 7 (PD 7) in C57BL/6 (B6) mice produced profound spatial learning deficits in the Morris water maze when tested in adolescence (P30-39); when tested in adulthood, however, the deficits were greatly attenuated. Using a similar PD 7 binge alcohol exposure paradigm in B6 mice, we tested whether a single-day (PD 7 only) alcohol treatment produced place learning deficits in both adolescence and in adulthood, and further tested whether a more extended (3-day, PD 7-9) alcohol exposure would induce more severe and enduring deficits. B6 mice were given either 2 subcutaneous injections of alcohol (2.5 g/kg each) 2 h apart on PD 7 or on PD 7-9, and compared with controls that received saline vehicle injections and controls that received no injections. The alcohol injections on PD 7 produced average peak blood alcohol concentrations of 472 mg/dL and evoked typical patterns of activated caspase-3-positive neurons in the cortex, hippocampal formation, and striatum 6 h after the last injection. Mice were given standard place training or random location training in the Morris water maze either as adolescents (PD 30-39) or adults (PD 70-79). The adolescents acquired the place learning more slowly than adults, and the alcohol treatments produced only modest place acquisition deficits. In contrast, both the PD7 and the PD 7-9 alcohol treatments resulted in large and significant spatial learning impairments in adults. In contrast to the previous findings of Wozniak et al. (2004), these results indicate that binge alcohol exposure in the 3rd trimester equivalent produces significant and enduring deficits in spatial learning in B6 mice.

Neurobehavioral, neurologic, and neuroimaging characteristics of fetal alcohol spectrum disorders

Alcohol consumption during pregnancy can have deleterious consequences for the fetus, including changes in central nervous system development leading to permanent neurologic alterations and cognitive and behavioral deficits. Individuals affected by prenatal alcohol exposure, including those with and without fetal alcohol syndrome, are identified under the umbrella of fetal alcohol spectrum disorders (FASD). While studies of humans and animal models confirm that even low to moderate levels of exposure can have detrimental effects, critical doses of such exposure have yet to be specified and the most clinically significant and consistent consequences occur following heavy exposure. These consequences are pervasive, devastating, and can result in long-term dysfunction. This chapter summarizes the neurobehavioral, neurologic, and neuroimaging characteristics of FASD, focusing primarily on clinical research of individuals with histories of heavy prenatal alcohol exposure, although studies of lower levels of exposure, particularly prospective, longitudinal studies, will be discussed where relevant.

Glia and neurodevelopment: focus on fetal alcohol spectrum disorders

During the last 20 years, new and exciting roles for glial cells in brain development have been described. Moreover, several recent studies implicated glial cells in the pathogenesis of neurodevelopmental disorders including Down syndrome, Fragile X syndrome, Rett Syndrome, Autism Spectrum Disorders, and Fetal Alcohol Spectrum Disorders (FASD). Abnormalities in glial cell development and proliferation and increased glial cell apoptosis contribute to the adverse effects of ethanol on the developing brain and it is becoming apparent that the effects of fetal alcohol are due, at least in part, to effects on glial cells affecting their ability to modulate neuronal development and function. The three major classes of glial cells, astrocytes, oligodendrocytes, and microglia as well as their precursors are affected by ethanol during brain development. Alterations in glial cell functions by ethanol dramatically affect neuronal development, survival, and function and ultimately impair the development of the proper brain architecture and connectivity. For instance, ethanol inhibits astrocyte-mediated neuritogenesis and oligodendrocyte development, survival and myelination; furthermore, ethanol induces microglia activation and oxidative stress leading to the exacerbation of ethanol-induced neuronal cell death. This review article describes the most significant recent findings pertaining the effects of ethanol on glial cells and their significance in the pathophysiology of FASD and other neurodevelopmental disorders.

Primary visual response (M100) delays in adolescents with FASD as measured with MEG

Fetal alcohol spectrum disorders (FASD) are debilitating, with effects of prenatal alcohol exposure persisting into adolescence and adulthood. Complete characterization of FASD is crucial for the development of diagnostic tools and intervention techniques to decrease the high cost to individual families and society of this disorder. In this experiment, we investigated visual system deficits in adolescents (12-21 years) diagnosed with an FASD by measuring the latency of patients' primary visual M100 responses using MEG. We hypothesized that patients with FASD would demonstrate delayed primary visual responses compared to controls. M100 latencies were assessed both for FASD patients and age-matched healthy controls for stimuli presented at the fovea (central stimulus) and at the periphery (peripheral stimuli; left or right of the central stimulus) in a saccade task requiring participants to direct their attention and gaze to these stimuli. Source modeling was performed on visual responses to the central and peripheral stimuli and the latency of the first prominent peak (M100) in the occipital source timecourse was identified. The peak latency of the M100 responses were delayed in FASD patients for both stimulus types (central and peripheral), but the difference in latency of primary visual responses to central vs. peripheral stimuli was significant only in FASD patients, indicating that, while FASD patients' visual systems are impaired in general, this impairment is more pronounced in the periphery. These results suggest that basic sensory deficits in this population may contribute to sensorimotor integration deficits described previously in this disorder.

Effects of early postnatal alcohol exposure on the developing retinogeniculate projections in C57BL/6 mice

Previous studies on the adverse effects of perinatal exposure to ethanol (EtOH) on the developing visual system mainly focused on retinal and optic nerve morphology. The aim of the present study was to investigate whether earlier reported retinal and optic nerve changes are accompanied by anomalies in eye-specific fiber segregation in the dorsal lateral geniculate nucleus (dLGN). C57BL/6 mice pups were exposed to ethanol by intragastric intubation at either 3 or 4 g/kg from postnatal days (PD) 3-10, the third trimester equivalent to human gestation. Control (C) and intubation control (IC) groups not exposed to ethanol were included. On PD9, retinogeniculate projections were labeled by intraocular microinjections of cholera toxin-β (CTB) either conjugated to Alexa 488 (green) or 594 (red) administrated to the left and right eye, respectively. Pups were sacrificed 24 h after the last CTB injection. The results showed that ethanol exposure decreased the total number of dLGN neurons and significantly reduced the total dLGN projection as well as the contralateral and ipsilateral projection areas.

Overexpression of serum response factor in astrocytes improves neuronal plasticity in a model of early alcohol exposure

Neuronal plasticity deficits underlie many of the cognitive problems seen in fetal alcohol spectrum disorders (FASD). We have developed a ferret model showing that early alcohol exposure leads to a persistent disruption in ocular dominance (OD) plasticity. Recently, we showed that this deficit could be reversed by overexpression of serum response factor (SRF) in the primary visual cortex during the period of monocular deprivation (MD). Surprisingly, this restoration was observed throughout the extent of visual cortex and most of the cells transfected by the virus were positive for the astrocytic marker GFAP rather than the neuronal marker NeuN. Here we test whether overexpression of SRF exclusively in astrocytes is sufficient to restore OD plasticity in alcohol-exposed ferrets. To accomplish that, first we exposed cultured astrocytes to Sindbis viruses carrying either a constitutively active form of SRF (SRF+), a dominant negative (SRF-) or control Green Fluorescent Protein (GFP). After 24h, these astrocytes were implanted in the visual cortex of alcohol-exposed animals or saline controls one day before MD. Optical imaging of intrinsic signals showed that alcohol-exposed animals that were implanted with astrocytes expressing SRF, but not SRF- or GFP, showed robust restoration of OD plasticity in all visual cortex. These findings suggest that overexpression of SRF exclusively in astrocytes can improve neuronal plasticity in FASD.

Children with fetal alcohol spectrum disorder show an amblyopia-like pattern of vision deficit

AIM

The aim of the study was to assess and characterize visual functioning in children with fetal alcohol spectrum disorder (FASD) using a broader and more inclusive range of measures than has been reported previously.

METHOD

Standard tests of visual functioning were used to assess 21 children (11 females, 10 males) with FASD and 21 sex- and age-matched comparison children without FASD. The age of the children ranged from 6 years 9 months to 11 years 11 months (mean 9y 6mo). Children were tested individually under standardized conditions for visual acuity, stereoacuity, contrast sensitivity, ocular alignment/motility, color vision, and refractive error.

RESULTS

Compared with non-affected children, children with FASD showed deficits in visual acuity, contrast sensitivity, and stereoacuity. Ocular alignment/motility, refractive error, and color vision measures were normal. Among children with FASD, 62% met the criteria for referral to an eye specialist, compared with 20% of children without FASD.

INTERPRETATION

Children with FASD showed an amblyopia-like pattern of vision deficit in the absence of the optical and oculomotor disruptions of early experience that usually precede this condition. Evidence from animal models suggests that the deficits in spatial vision may be due to alterations in the functional architecture of the neocortex that occurs following prenatal alcohol exposure.

Effects of early postnatal exposure to ethanol on retinal ganglion cell morphology and numbers of neurons in the dorsolateral geniculate in mice

BACKGROUND

The adverse effects of fetal and early postnatal ethanol intoxication on peripheral organs and the central nervous system are well documented. Ocular defects have also been reported in about 90% of children with fetal alcohol syndrome, including microphthalmia, loss of neurons in the retinal ganglion cell (RGC) layer, optic nerve hypoplasia, and dysmyelination. However, little is known about perinatal ethanol effects on retinal cell morphology. Examination of the potential toxic effects of alcohol on the neuron architecture is important because the changes in dendritic geometry and synapse distribution directly affect the organization and functions of neural circuits. Thus, in the present study, estimations of the numbers of neurons in the ganglion cell layer and dorsolateral geniculate nucleus (dLGN), and a detailed analysis of RGC morphology were carried out in transgenic mice exposed to ethanol during the early postnatal period.

METHODS

The study was carried out in male and female transgenic mice expressing yellow fluorescent protein (YFP) controlled by a Thy-1 (thymus cell antigen 1) regulator on a C57 background. Ethanol (3 g/kg/d) was administered to mouse pups by intragastric intubation throughout postnatal days (PDs) 3 to 20. Intubation control (IC) and untreated control (C) groups were included. Blood alcohol concentration was measured in separate groups of pups on PDs 3, 10, and 20 at 4 different time points, 1, 1.5, 2, and 3 hours after the second intubation. Numbers of neurons in the ganglion cell layer and in the dLGN were quantified on PD20 using unbiased stereological procedures. RGC morphology was imaged by confocal microscopy and analyzed using Neurolucida software.

RESULTS

Binge-like ethanol exposure in mice during the early postnatal period from PDs 3 to 20 altered RGC morphology and resulted in a significant decrease in the numbers of neurons in the ganglion cell layer and in the dLGN. In the alcohol exposure group, out of 13 morphological parameters examined in RGCs, soma area was significantly reduced and dendritic tortuosity significantly increased. After neonatal exposure to ethanol, a decrease in total dendritic field area and an increase in the mean branch angle were also observed. Interestingly, RGC dendrite elongation and a decrease in the spine density were observed in the IC group, as compared to both ethanol-exposed and pure control subjects. There were no significant effects of alcohol exposure on total retinal area.

CONCLUSIONS

Early postnatal ethanol exposure affects development of the visual system, reducing the numbers of neurons in the ganglion cell layer and in the dLGN, and altering RGCs' morphology.

A novel, non-stop mutation in FOXE3 causes an autosomal dominant form of variable anterior segment dysgenesis including Peters anomaly

Anterior segment dysgenesis (ASD) is a spectrum of disorders that affect the anterior ocular chamber. Clinical studies on a Newfoundland family over the past 30 years show that 11 relatives have a variable ocular phenotype ranging from microcornea to Peters anomaly, segregating as an autosomal dominant trait. To determine the molecular etiology of the variable ASD in this family, we sequenced nine functional candidate genes and identified 44 variants. A point mutation in FOXE3, which codes for a transcription factor involved in the formation of the lens and surrounding structures, co-segregated with the variable ocular phenotype. This novel mutation (c.959G>T) substitutes the stop codon for a leucine residue, predicting the addition of 72 amino acids to the C-terminus of FOXE3. Two recent reports have also identified non-stop mutations in FOXE3 in patients with variable ocular phenotypes and predict an extended protein. Although FOXE3 is a lens-specific gene, we successfully isolated complementary DNA from lymphoblasts of an affected family member, and our sequencing results show that the c.959T allele is absent, suggesting that it may be degraded at the RNA level. Though preliminary, our results challenge the notion that an extended FOXE3 protein causes ASD, and instead suggests a mechanism of haploinsufficiency in the case of non-stop mutations. This study adds to several reports that suggest that autosomal-dominant mutations within FOXE3 cause ASD and has important clinical utility, especially for the diagnosis of mildly affected patients.

Prenatal alcohol exposure and neurodevelopmental disorders in children adopted from eastern Europe

OBJECTIVES

The purposes of this investigation were to determine the frequencies of and associations between different neurodevelopmental disorders and to study the potential lasting effects of alcohol on children adopted from eastern Europe.

METHODS

In a population-based, prospective, observational, multidisciplinary, cross-sectional, cohort study of 71 children adopted from eastern Europe, children were assessed 5 years after adoption, from pediatric, neuropsychological, and ophthalmologic perspectives.

RESULTS

Fetal alcohol spectrum disorders, that is, fetal alcohol syndrome (FAS), partial FAS, and alcohol-related neurodevelopmental disorders, were identified for 52% of children; FAS was found for 30%, partial FAS for 14%, and alcohol-related neurodevelopmental disorders for 9%. Alcohol-related birth defects were found for 11% of children, all of whom also were diagnosed as having FAS. Mental retardation or significant cognitive impairment was found for 23% of children, autism for 9%, attention-deficit/hyperactivity disorder for 51%, and developmental coordination disorder for 34%.

CONCLUSIONS

Fetal alcohol spectrum disorders and neurodevelopmental disorders were common in this long-term follow-up study of children adopted from orphanages in eastern Europe. Maternal alcohol consumption during pregnancy has long-lasting adverse effects, causing structural, behavioral, and cognitive damage despite a radically improved environment.

Prevalence and epidemiologic characteristics of FASD from various research methods with an emphasis on recent in-school studies

Researching the epidemiology and estimating the prevalence of fetal alcohol syndrome (FAS) and other fetal alcohol spectrum disorders (FASD) for mainstream populations anywhere in the world has presented a challenge to researchers. Three major approaches have been used in the past: surveillance and record review systems, clinic-based studies, and active case ascertainment methods. The literature on each of these methods is reviewed citing the strengths, weaknesses, prevalence results, and other practical considerations for each method. Previous conclusions about the prevalence of FAS and total FASD in the United States (US) population are summarized. Active approaches which provide clinical outreach, recruitment, and diagnostic services in specific populations have been demonstrated to produce the highest prevalence estimates. We then describe and review studies utilizing in-school screening and diagnosis, a special type of active case ascertainment. Selected results from a number of in-school studies in South Africa, Italy, and the US are highlighted. The particular focus of the review is on the nature of the data produced from in-school methods and the specific prevalence rates of FAS and total FASD which have emanated from them. We conclude that FAS and other FASD are more prevalent in school populations, and therefore the general population, than previously estimated. We believe that the prevalence of FAS in typical, mixed-racial, and mixed-socioeconomic populations of the US is at least 2 to 7 per 1,000. Regarding all levels of FASD, we estimate that the current prevalence of FASD in populations of younger school children may be as high as 2-5% in the US and some Western European countries.

Mechanisms underlying spontaneous patterned activity in developing neural circuits

Patterned, spontaneous activity occurs in many developing neural circuits, including the retina, the cochlea, the spinal cord, the cerebellum and the hippocampus, where it provides signals that are important for the development of neurons and their connections. Despite there being differences in adult architecture and output across these various circuits, the patterns of spontaneous network activity and the mechanisms that generate it are remarkably similar. The mechanisms can include a depolarizing action of GABA (gamma-aminobutyric acid), transient synaptic connections, extrasynaptic transmission, gap junction coupling and the presence of pacemaker-like neurons. Interestingly, spontaneous activity is robust; if one element of a circuit is disrupted another will generate similar activity. This research suggests that developing neural circuits exhibit transient and tunable features that maintain a source of correlated activity during crucial stages of development.

Characterization of white matter microstructure in fetal alcohol spectrum disorders

BACKGROUND

Exposure to alcohol during gestation is associated with CNS alterations, cognitive deficits, and behavior problems. This study investigated microstructural aspects of putative white matter abnormalities following prenatal alcohol exposure.

METHODS

Diffusion tensor imaging was used to assess white matter microstructure in 27 youth (age range: 8 to 18 years) with (n = 15) and without (n = 12) histories of heavy prenatal alcohol exposure. Voxelwise analyses, corrected for multiple comparisons, compared fractional anisotropy (FA) and mean diffusivity (MD) between groups, throughout the cerebrum.

RESULTS

Prenatal alcohol exposure was associated with low FA in multiple cerebral areas, including the body of the corpus callosum and white matter innervating bilateral medial frontal and occipital lobes. Fewer between-group differences in MD were observed.

CONCLUSIONS

These data provide an account of cerebral white matter microstructural integrity in fetal alcohol spectrum disorders and support extant literature showing that white matter is a target of alcohol teratogenesis. The white matter anomalies characterized in this study may relate to the neurobehavioral sequelae associated with gestational alcohol exposure, especially in areas of executive dysfunction and visual processing deficits.

Eye malformations in children with heavy alcohol exposure in utero

OBJECTIVE

To determine whether children who do not develop fetal alcohol syndrome (FAS) despite heavy alcohol exposure are at risk for eye abnormalities.

STUDY DESIGN

We screened 9628 pregnant women and identified 101 women who were drinking >/= 2 oz of absolute alcohol per day and 101 nondrinking control women. We followed 43 exposed and 55 control offspring between age 4 and 9 years, performing masked standardized ophthalomologic examinations.

RESULTS

The groups did not differ in their rates of impaired visual acuity, refractory errors, ptosis, epicanthal folds, or short palpebral fissures. Biomicroscopy examination was normal in all exposed subjects; cataracts were detected in 2 control subjects (4%) but in no exposed subjects. Arterial tortuosity was seen in 7 exposed subjects (16%) and in 8 control subjects (15%). Optic nerve hypoplasia was not detected in any subject.

CONCLUSIONS

Previous research has found that children with FAS have a high incidence of serious ophthalmologic defects; our data indicate that the risk is limited to children with FAS and does not extend to children exposed to high levels of alcohol prenatally who do not develop FAS. Eye examinations are unlikely to clarify the diagnosis in children suspected of having alcohol-related damage.

Optic nerve hypoplasia potentiates retinopathy of prematurity

The risk of progression to threshold retinopathy of prematurity correlates with the area of avascular retinas and inversely with the degree of vascular maturity. Asymmetric retinal ablation was performed in two patients and asymmetric retinopathy of prematurity progression was observed in two infants with optic nerve hypoplasia.

Alcohol exposure during the first two trimesters-equivalent alters the development of corpus callosum projection neurons in the rat

Children exposed prenatally to alcohol can display a variety of neural deficits, including an altered development of the corpus callosum (CC), the largest interhemispheric axon pathway in the brain. Furthermore, these children show functional abnormalities that are related to brain regions with significant numbers of CC connections. Little is known about how alcohol imparts influence on CC development, but one possible mechanism is by affecting the corpus callosum projection neurons (CCpn) directly. The purpose of this study was to quantify the effects of prenatal alcohol exposure on the number, size, and distribution of CCpn within the visual cortex. The visual cortex was selected specifically due to the many vision-related deficits noted in fetal alcohol exposed children and because the critical role of the CC in visual cortex development is well documented. Sprague-Dawley rat pups received one of four alcohol dosages during gestational days (G) 1-20, or reared as nutritional or untreated control animals. Each litter was categorized according to the peak blood alcohol concentration experienced. Pups were removed from each litter on days equivalent to G29, G36, G43, and G50, for histology and measurement. Callosal axons were labeled retrogradely to their CCpn using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) and the CCpn were then examined using confocal laser scanning microscopy. Differences between alcohol-exposed and control animals were observed in CCpn cell body size, number, and location with the cortex. This was particularly true of animals exposed to high doses of alcohol. In addition, some trends of CCpn development were found to be unchanged as a result of prenatal alcohol exposure. The results demonstrate clear differences in the development of CCpn in the visual cortex between alcohol-exposed and control animals and suggest that this development is particularly affected in those animals exposed to high doses of alcohol.

GABA(A) receptor-mediated signaling alters the structure of spontaneous activity in the developing retina

Ambient GABA modulates firing patterns in adult neural circuits by tonically activating extrasynaptic GABA(A) receptors. Here, we demonstrate that during a developmental period when activation of GABA(A) receptors causes membrane depolarization, tonic activation of GABA(A) receptors blocks all spontaneous activity recorded in retinal ganglion cells (RGCs) and starburst amacrine cells (SACs). Bath application of the GABA(A) receptor agonist muscimol blocked spontaneous correlated increases in intracellular calcium concentration and compound postsynaptic currents in RGCs associated with retinal waves. In addition, GABA(A) receptor agonists activated a tonic current in RGCs that significantly reduced their excitability. Using a transgenic mouse in which green fluorescent protein is expressed under the metabotropic glutamate receptor subtype 2 promoter to target recordings from SACs, we found that GABA(A) receptor agonists blocked compound postsynaptic currents and also activated a tonic current. GABA(A) receptor antagonists reduced the holding current in SACs but not RGCs, indicating that ambient levels of GABA tonically activate GABA(A) receptors in SACs. GABA(A) receptor antagonists did not block retinal waves but did alter the frequency and correlation structure of spontaneous RGC firing. Interestingly, the drug aminophylline, a general adenosine receptor antagonist used to block retinal waves, induced a tonic GABA(A) receptor antagonist-sensitive current in outside-out patches excised from RGCs, indicating that aminophylline exerts its action on retinal waves by direct activation of GABA(A) receptors. These findings have implications for how various neuroactive drugs and neurohormones known to modulate extrasynaptic GABA(A) receptors may influence spontaneous firing patterns that are critical for the establishment of adult neural circuits.

Ocular deficits associated with alcohol exposure during zebrafish development

Approximately 90% of fetal alcohol syndrome cases are accompanied by ocular abnormalities. The zebrafish (Danio rerio) is a well-known developmental model that provides an opportunity for better understanding the histological and cytological effects of developmental exposure to ethanol on the vertebrate eye. The purpose of the present study was to determine the gross, microscopic, and ultrastructual effects of developmental exposure to ethanol in the zebrafish model. Eggs were obtained from WT outbred zebrafish and exposed to 0%, 0.1%, 0.2%, 0.4%, 0.5%, or 1.0% (v/v) ethanol to assess viability and the effect of dose and duration of exposure on eye size. Light and electron microscopy were performed on ethanol-treated and control larvae. Results showed that ethanol treatment decreased viability by about 20% at concentrations of 0.1-0.5% ethanol and by 50% at 1.0% ethanol. Ethanol-related decreases in eye size were recorded at 6 days postfertilization (dpf) and were dose dependent. There were significant decreases in the volumes of the photoreceptor, inner nuclear, and ganglionic layers and in the lens of 9 dpf ethanol-exposed compared with control larvae. Ultrastructural examination showed signs of developmental lags in the ethanol-treated fish as well as abnormal retinal apoptosis in the 6 dpf ethanol-treated larvae compared with their controls. These results demonstrate that the developing zebrafish eye is sensitive to perturbation with ethanol and displays some of the eye deficits present in fetal alcohol syndrome.