The phenotypic spectrum associated with OTX2 mutations in humans.

Objective: The transcription factor OTX2 is implicated in ocular, craniofacial, and pituitary development. Design: We aimed to establish the contribution of OTX2 mutations in congenital hypopituitarism patients with/without eye abnormalities, study functional consequences, and establish OTX2 expression in the human brain, with a view to investigate the mechanism of action. Methods: We screened patients from the UK (n = 103), international centres (n = 24), and Brazil (n = 282); 145 were within the septo-optic dysplasia spectrum, and 264 had no eye phenotype. Transactivation ability of OTX2 variants was analysed in murine hypothalamic GT1-7 neurons. In situ hybridization was performed on human embryonic brain sections. Genetically engineered mice were generated with a series of C-terminal OTX2 variants. Results: Two chromosomal deletions and six haploinsufficient mutations were identified in individuals with eye abnormalities; an affected relative of one patient harboured the same mutation without an ocular phenotype. OTX2 truncations led to significant transactivation reduction. A missense variant was identified in another patient without eye abnormalities; however, studies revealed it was most likely not causative. In the mouse, truncations proximal to aa219 caused anophthalmia, while distal truncations and the missense variant were tolerated. During human embryogenesis, OTX2 was expressed in the posterior pituitary, retina, ear, thalamus, choroid plexus, and partially in the hypothalamus, but not in the anterior pituitary. Conclusions: OTX2 mutations are rarely associated with hypopituitarism in isolation without eye abnormalities, and may be variably penetrant, even within the same pedigree. Our data suggest that the endocrine phenotypes in patients with OTX2 mutations are of hypothalamic origin.

A novel proline substitution (Arg201Pro) in alpha helix 8 of TMEM98 causes autosomal dominant nanophthalmos-4, closed angle glaucoma and attenuated visual acuity.

Nanophthalmos-4 is a rare autosomal dominant disorder caused by two known variations in TMEM98. An Austrian Caucasian pedigree was identified suffering from nanophthalmos and late onset angle-closure glaucoma and premature loss of visual acuity. Whole exome sequencing identified segregation of a c.602G > C transversion in TMEM98 (p.Arg201Pro) as potentially causative. A protein homology model generated showed a TMEM98 structure comprising α4, α5/6, α7 and α8 antiparallel helix bundles and two predicted transmembrane domains in α1 and α7 that have been confirmed in vitro. Both p.Arg201Pro and the two missense variations representing proline insertions identified previously to cause nanophthalmos-4 (p.Ala193Pro and p.His196Pro) are located in the charge polarized helix α8 (p.183-p210). Stability of the C-terminal alpha helical structure of TMEM98 is therefore essential to prevent the development of human nanophthalmos-4. Precise molecular diagnosis could lead to the development of tailored therapies for patients with orphan ocular disease.

Clinical spectrum of non-syndromic microphthalmos, anophthalmos and coloboma in the paediatric population: a multicentric study from North India.

AIMS: To describe the clinical features, visual acuity and causes of ocular morbidity in children (0-18 years) with microphthalmos, anophthalmos, and coloboma (MAC) from North India. METHODS: A retrospective study conducted between October 2017 and September 2018 in three tertiary eye institutes, part of the Bodhya Eye Consortium with consensus led common pro formas. Children with complete clinical data and without syndromic/systemic involvement were included. The clinical phenotype was divided into isolated ocular coloboma (CB), coloboma with microcornea (CBMC), colobomatous microphthalmos (CBMO), non-colobomatous microphthalmos (MO) and anophthalmos (AO). RESULTS: A total of 532 children with MAC were examined. Seventeen records were excluded due to incomplete data (0.2%). 515 children (845 eyes) were included: 54.4% males and 45.6% females. MAC was unilateral in 36% and bilateral in 64%. CB, CBMC, CBMO, MO and AO were seen in 26.4%, 31%, 22%, 8% and 12.5% of eyes, respectively. Nystagmus was found in 40%, strabismus in 23%, cataract in 18.7% and retinal detachment in 15%. Best-corrected visual acuity (BCVA) of <3/60 was seen in 62.4% eyes. Blindness (BCVA <3/60 in better eye) was seen in 42.8% of bilateral patients. Those with microcornea or microphthalmos with coloboma had worse BCVA (p<0.001). There were regional differences in the type of MAC phenotype presenting to the three institutes. CONCLUSION: The MAC group of disorders cause significant ocular morbidity. The presence of microcornea or microphthalmos with coloboma predicts worse BCVA. The variation of the MAC phenotype with the district of origin of the patient raises questions of aetiology and is subject to further studies.

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.

Características clínicas y análisis de OCT de una serie de casos de microftalmos posterior / Clinical characteristics and OCT analysis of a case series of posterior microphthalmos

El microftalmos posterior es un cuadro poco frecuente que puede encontrarse en pacientes pediátricos con hipermetropía elevada y visión reducida. Presentamos un estudio retrospectivo de 5casos de microftalmía posterior en niños de edades comprendidas entre 4 y 13 años. Se obtuvieron los siguientes parámetros: agudeza visual, refracción bajo cicloplejía, biometría, examen en lámpara de hendidura, presión intraocular y ecografía ocular. La refracción, la longitud axial y la agudeza visual media fueron de +15,35 Dp; 16,20 mm y 0,13, respectivamente. Se examinó el fondo de ojo, se realizó tomografía de coherencia óptica y, en uno de los casos, retinografía y angiografía fluoresceínica. En todos los casos se evidenció ausencia de depresión foveal y diferentes morfotipos del pliegue papilo-macular por tomografía. Al no existir un tratamiento específico, es importante una adecuada detección, manejo y seguimiento de esta enfermedad para mejorar y mantener la visión de los pacientes y reconocer posibles complicaciones

Posterior microphthalmos is a rare condition that can be found in paediatric patients with increased farsightedness and reduced vision. A retrospective study is presented of 5 cases of posterior microphthalmia aged between 4 and 13 years. The following parameters were obtained: visual acuity, cycloplegic refractive error, optical biometry, slit lamp examination, intraocular pressure, and ocular ultrasound. The refraction, axial length and average visual acuity was + 15.35 Dp, 16.20 mm and 0.13, respectively. The fundus was examined, optical coherence tomography was performed, and also retinography and fluorescein angiography in one case. In all cases, the absence of foveal depression and different morphotypes of the papillo-macular fold were observed in the tomography. In the absence of a specific treatment, the appropriate detection, management, and monitoring of this disease is important to improve and maintain the vision of patients and recognise possible complications

Nanophthalmos in children: morphometric and clinical characterization.

PURPOSE: To report clinical and morphometric characteristics of children with nanophthalmos and to identify possible risk factors associated with occludable angles. METHODS: The medical records of children (<18 years of age) with nanophthalmos examined from January 2016 to December 2016 were reviewed retrospectively. Demographic and examination details, including cycloplegic refraction, best-corrected visual acuity, intraocular pressure (IOP), gonioscopy, and fundus examination, were extracted for analysis. Biometric data included axial length, anterior chamber depth, and lens thickness. Subgroup data from children with occludable and open angles on gonioscopy were compared. RESULTS: A total of 75 children were included. Mean age at presentation was 10.92 ± 4.97 years. Mean spherical equivalent was +13.31 ± 2.69 D. Best-corrected visual acuity was 20/40 or better in 26 eyes (35%). Ametropic amblyopia was leading cause of visual impairment in our series. IOP was within normal limits (10-21 mm Hg) in 73 subjects and above normal in 2. Of the 75 children, 17 had occludable angles. Posterior segment anomalies were found in 28. Mean axial length was 16.88 ± 1.5 mm, mean anterior chamber depth was 3.00 ± 0.5 mm, and mean lens thickness was 3.9 ± 0.5 mm. The ratio of lens thickness to axial length was 0.253 ± 0.025 in subjects with occludable angles; 0.226 ± 0.038, in those with open angle. A ratio of >0.239 increased the risk of having angle closure by nearly three times. CONCLUSIONS: In this study cohort, nanophthalmos was characterized by short axial length and high hyperopia, with shallow anterior chamber. Nearly 20% of children had occludable angles requiring intervention. Clinicians should monitor the ratio of lens thickness to axial length to ensure that angle closure is prevented.

A fetal case of microphthalmia and limb anomalies with abnormal neuronal migration associated with SMOC1 biallelic variants.

Microphthalmia with limb anomalies (MLA, OMIM, 206920) is a rare autosomal-recessive disease caused by biallelic pathogenic variants in the SMOC1 gene. It is characterized by ocular disorders (microphtalmia or anophtalmia) and limb anomalies (oligodactyly, syndactyly, and synostosis of the 4th and 5th metacarpals), variably associated with long bone hypoplasia, horseshoe kidney, venous anomalies, vertebral anomalies, developmental delay, and intellectual disability. Here, we report the case of a woman who interrupted her pregnancy after ultrasound scans revealed a depression of the frontal bone, posterior fossa anomalies, cerebral ventricular enlargement, cleft spine involving the sacral and lower-lumbar vertebrae, and bilateral microphthalmia. Micrognathia, four fingers in both feet and a slight tibial bowing were added to the clinical picture after fetal autopsy. Exome sequencing identified two variants in the SMOC1 gene, each inherited from one of the parents: c.709G>T - p.(Glu237*) on exon 8 and c.1223G>A - p.(Cys408Tyr) on exon 11, both predicted to be pathogenic by different bioinformatics software. Brain histopathology showed an abnormal cortical neuronal migration, which could be related to the SMOC1 protein function, given its role in cellular signaling, proliferation and migration. Finally, we summarize phenotypic and genetic data of known MLA cases showing that our case has some unique features (Chiari II malformation; focal neuropathological alterations) that could be part of the variable phenotype of SMOC1-associated diseases.

The role of corneo-scleral junction in soft contact lens fitting: Case report on nanophthalmos.

BACKGROUND: Nanophthalmos is rare developmental ocular condition characterized by a small eye with short axial length, high hyperopia and high lens to eye volume ratio due to arrested development of eye ball as a result of scleral inelasticity. OBSERVATIONS: A 33 year old woman who presented with a complaint of blurring of distance and near vision in both eyes since childhood came to LV Prasad Eye Institute on July 2017. Best corrected visual acuity was 20/60 using soft contact lens +23.50 diopters for the right and left eyes. Axial lengths of two eyes were markedly shortened along with steep corneal curvatures. Visante anterior segment ocular coherence tomography showed a steep (convex) corneo-scleral junction (CSJ) which might be the reason for ill-fitting with conventionally estimated soft contact lens (SCL) parameters. Finally, selection of the customized hydrogel soft contact lens base curve close to flatter corneal curvature and small diameter showed characteristics of optimal lens fit. CONCLUSION: The corneo-scleral junction profile plays significant role in soft contact lens fitting. An eye with a profile of convex CSJ would require a lens with steeper curvature compared to conventional measurements. Cases of nanophthalmos would require observation of the profile with the help of optical coherence tomography in addition to measurement of corneal curvature prior to fitting soft contact lenses.

Functional vision and quality of life in children with microphthalmia/anophthalmia/coloboma-a cross-sectional study.

PURPOSE: To determine the child's and parental perception of functional visual ability (FVA), vision-related and health-related quality of life (VR-QoL, HR-QoL) in children with microphthalmia/anophthalmia/coloboma (MAC). METHODS: Between June 25, 2014, and June 3, 2015, we carried out a cross-sectional observational study at Moorfields Eye Hospital, London, UK, enrolling 45 children 2-16 years of age with MAC attending our clinics, and their parents. To assess FVA, VR-QoL, and HR-QoL we asked participants to complete three validated tools, the Cardiff Visual Ability Questionnaire for Children (CVAQC), the Impact of Vision Impairment for Children (IVI-C) instrument, and the PedsQL V 4.0. The main outcome measures were the FVA, VR-QoL, and HR-QoL scores, reported by children and parents. RESULTS: In children with MAC, FVA is moderately reduced, with a median CVAQC score of -1.4 (IQR, -2.4 to 0.4; range, -3.0 [higher FVA] to +2.8 [lower FVA]). VR-QoL and HR-QoL are greatly reduced, with an IVI-C median score of 63 (IQR, 52-66; normal VR-QoL, 96), a median self-reported PedsQL score of 77 (IQR, 71-90; normal HR-QoL, 100) and parental score of 79 (IQR, 61-93), and a family impact score of 81 (67-93). Psychosocial well-being scores are lower than physical well-being scores. Parents and children have a different perception of the impact of the condition on the child's HR-QoL. CONCLUSIONS: MAC has a significant impact on a child's FVA and QoL, similar to that described by children with acute lymphoblastic leukaemia and chronic systemic conditions. Children and families may benefit from psychosocial support.

A zebrafish model of foxe3 deficiency demonstrates lens and eye defects with dysregulation of key genes involved in cataract formation in humans.

The Forkhead box E3 (FOXE3) gene encodes a transcription factor with a forkhead/winged helix domain that is critical for development of the lens and anterior segment of the eye. Monoallelic and biallelic deleterious sequence variants in FOXE3 cause aphakia, cataracts, sclerocornea and microphthalmia in humans. We used clustered regularly interspaced short palindromic repeats/Cas9 injections to target the foxe3 transcript in zebrafish in order to create an experimental model of loss of function for this gene. Larvae that were homozygous for an indel variant, c.296_300delTGCAG, predicting p.(Val99Alafs*2), demonstrated severe eye defects, including small or absent lenses and microphthalmia. The lenses of the homozygous foxe3 indel mutants showed more intense staining with zl-1 antibody compared to control lenses, consistent with increased lens fiber cell differentiation. Whole genome transcriptome analysis (RNA-Seq) on RNA isolated from wildtype larvae and larvae with eye defects that were putative homozygotes for the foxe3 indel variant found significant dysregulation of genes expressed in the lens and eye whose orthologues are associated with cataracts in human patients, including cryba2a, cryba1l1, mipa and hsf4. Comparative analysis of this RNA-seq data with iSyTE data identified several lens-enriched genes to be down-regulated in foxe3 indel mutants. We also noted upregulation of lgsn and crygmxl2 and downregulation of fmodb and cx43.4, genes that are expressed in the zebrafish lens, but that are not yet associated with an eye phenotype in humans. These findings demonstrate that this new zebrafish foxe3 mutant model is highly relevant to the study of the gene regulatory networks conserved in vertebrate lens and eye development.

CLINICAL APPRAISAL AND RETINAL IMAGING IN POSTERIOR MICROPHTHALMOS.

PURPOSE: To report a critical case series of five patients with posterior microphthalmos and the review of their clinical findings with the analyses of retinal imaging. METHOD: Case series. Complete ophthalmological examinations including optical coherence tomography (OCT) were evaluated. RESULTS: All patients had decreased visual acuity with high hyperopic refraction. Dilated fundus examination demonstrated that elevated papillomacular retinal folds with anterior segment were unremarkable. Total axial lengths measurements showed reduced axial lengths and B-scan ultrasonography revealed sclerochoroidal thickening. Moreover, papillomacular folds were confirmed by OCT. CONCLUSION: Dilated fundus examination, fundus fluorescein angiography, orbital ultrasonography, and proper OCT evaluation will be helpful to reach a diagnosis.

[Ocular dermoids and microphthalmia in a juvenile sheep]. / Okuläre Dermoide und Mikrophthalmie bei einem Jungschaf.

A 6-month-old Leine sheep was presented because of dermal tissue located on the left eye. During the first examination, the animal was clinically silent, apart from the deformed eye. A corneal and conjunctival dermoid and blindness of the left eye were diagnosed. Over a period of a year, the animal displayed conjunctivitis and inflammation of the affected eye. Furthermore, the sheep did not develop according to its age. During histopathological examination of the euthanized animal, microphthalmia and aphakia of the left eye were found in addition to the dermoids. Dermoids are described in humans and in different domestic animals. They can be combined with other congenital malformations. In sheep, dermoids are rarely diagnosed or reported in the literature.

FOXE3 mutations: genotype-phenotype correlations.

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

A heterozygous microdeletion of 20p12.2-3 encompassing PROKR2 and BMP2 in a patient with congenital hypopituitarism and growth hormone deficiency.

Congenital growth hormone deficiency is a rare disorder with an incidence of approximately 1 in 4,000 live births. Pituitary development is under the control of a multitude of spatiotemporally regulated signaling molecules and transcription factors. Mutations in the genes encoding these molecules can result in hypopituitarism but for the majority of children with congenital hypopituitarism, the aetiology of their disease remains unknown. The proband is a 5-year-old girl who presented with neonatal hypoglycaemia and prolonged jaundice. No definitive endocrine cause of hypoglycaemia was identified in the neonatal period. She was born of normal size at 42 weeks but demonstrated growth failure with a progressive reduction in height to -3.2 SD by age 4.5 years and failed a growth hormone stimulation test with a peak growth hormone of 4.2 mcg/L. MRI of the pituitary gland demonstrated a hypoplastic anterior lobe and ectopic posterior lobe. Array CGH demonstrated an inherited 0.2 Mb gain at 1q21.1 and a de novo 4.8 Mb heterozygous deletion at 20p12.2-3. The deletion contained 17 protein coding genes including PROKR2 and BMP2, both of which are expressed during embryological development of the pituitary gland. PROKR2 mutations have been associated with hypopituitarism but a heterozygous deletion of this gene with hypopituitarism is a novel observation. In conclusion, congenital hypopituitarism can be present in individuals with a 20p12.3 deletion, observed with incomplete penetrance. Array CGH may be a useful investigation in select cases of early onset growth hormone deficiency, and patients with deletions within this region should be evaluated for pituitary hormone deficiencies.

Image-guided lacrimal drainage surgery in congenital arhinia-microphthalmia syndrome.

The aim of this study was to illustrate the surgical techniques and utility of stereotactic or image-guided navigation in the management of lacrimal drainage obstruction in congenital arhinia-microphtalmia syndrome and review the relevant literature. Image-guided combined external and endoscopic dacryocystorhinostomy was performed in a female, aged 16 years with congenital partial arhinia and ipsilateral microphthalmus. The lacrimal sac was bypassed to the contra lateral nasal cavity through a septal window. The surgical procedure was performed using the intra-operative optical image-guided Nav 1 PicoTM ENT navigation system with real-time intra-operative instrument geometry. Different phases of the surgical technique, adjunctive endoscopic procedures, intra-operative anatomical guidance, and utility at crucial phases of surgery were noted. A review of the literature was performed pertinent to arhinia and navigation guided lacrimal surgeries. Lacrimal bypass into the contra lateral nasal cavity even through a malformed septum is possible in partial arhinia syndromes. Detailed preoperative evaluation including 3D imaging studies, navigation guided planning of risk structures with intra-operative distance control and construction of meticulous surgical roadmaps were found to be essential factors in successful outcomes. At six months follow up after surgery, there was a complete and contiguous healed mucosal anastomosis with lacrimal system patent on irrigation and resolution of epiphora. Combined external and endoscopic approach is useful in partial arhinia syndromes. Image guidance is a very useful adjunctive tool that facilitates safe and precise surgery in the management of such complex lacrimal surgeries.

Oculo-facio-cardio-dental syndrome with craniosynostosis, temporal hypertrichosis, and deafness.

We report the case of a 7-month-old girl with atypical oculo-facio-cardio-dental syndrome (OFCD). A novel de novo pathogenic mutation in the BCL6 interacting co-repressor gene (BCOR) (c.4540C>T; p.Arg1514*), was identified on the X chromosome. This case expands the phenotype of OFCD as it is the first report of a case presenting with craniosynostois, temporal hypertrichosis, supraorbital grooving, and underdevelopment of the midface.

Staying away from the optic nerve: a formula for modifying glaucoma drainage device surgery in pediatric and other small eyes.

PURPOSE: To provide guidelines for safe implantation of glaucoma drainage devices (GDDs) in small and pediatric eyes to avoid contact between the optic nerve (ON) and the posterior edge of the GDD plate. METHODS: We developed a formula for calculating limbus-to-ON distance to estimate the available "real estate" for GDD placement in small eyes. The formula was validated using eyes of pediatric decedents undergoing clinical autopsy, with axial lengths (AL) of 15-24 mm. For each autopsy eye, we measured AL, anterior chamber depth, corneal diameter, and limbus-to-ON distances for the four eye quadrants. The main outcome measure was the degree of agreement between measured and calculated limbus-to-ON distances. RESULTS: A total of 15 autopsy eyes were divided into derivation (n = 10) and validation (n = 5) groups. A formula was derived to estimate superotemporal limbus-to-ON distance (DST) using AL and corneal diameter data. Linear regression showed excellent correlation between the measured DST and AL (R2 = 0.98). There was excellent agreement between measured and calculated limbus-to-ON values for all four eye quadrants (R2 range, 0.92-0.98). CONCLUSIONS: Our formula accurately predicts limbus-to-ON distances across a wide range of clinically relevant ALs. Based on this information, GDD surgery in small eyes can be adjusted by positioning the GDD closer to the limbus or by trimming the posterior edge of the GDD plate. To our knowledge, this is the first set of guidelines developed to promote safe implantation of GDDs in small eyes.

Chornobyl 30 years later: Radiation, pregnancies, and developmental anomalies in Rivne, Ukraine.

In the 30 years since the Chornobyl nuclear power plant disaster, there is evidence of persistent levels of incorporated ionizing radiation in adults, children and pregnant women in the surrounding area. Measured levels of Cesium-137 vary by region, and may be influenced by dietary and water sources as well as proximity to nuclear power plants. Since 2000, comprehensive, population-based birth defects monitoring has been performed in selected regions of Ukraine to evaluate trends and to generate hypotheses regarding potential causes of unexplained variations in defect rates. Significantly higher rates of microcephaly, neural tube defects, and microphthalmia have been identified in selected regions of Ukraine collectively known as Polissia compared to adjacent regions collectively termed non-Polissia, and these significantly higher rates were evident particularly in the years 2000-2009. The Polissia regions have also demonstrated higher mean whole body counts of Cesium-137 compared to values in individuals residing in other non-Polissia regions. The potential causal relationship between persistent ionizing radiation pollution and selected congenital anomaly rates supports the need for a more thorough, targeted investigation of the sources of persistent ionizing radiation and the biological plausibility of a potential teratogenic effect.