Multiple prenatal ultrasound scans and ocular development: 20-year follow-up of a randomized controlled trial.

OBJECTIVES: Through comprehensive ophthalmic examination of adult offspring we sought to determine the impact of multiple prenatal ultrasound scans on ocular development. METHODS: 2743 pregnant women recruited to the Western Australian Pregnancy (Raine) Cohort study during 1989-1991 were randomized to receive at King Edward Memorial Hospital, Western Australia either multiple prenatal ultrasound scans and Doppler flow studies (intensive group) or a single ultrasound scan at 18 weeks' gestation. Neonatal birth weight of the offspring and other physical measurements were collected prospectively. At age 20 years, participants underwent a comprehensive ophthalmic examination including measurement of ocular biometry and visual acuity. RESULTS: Complete data were available for 1134 adult offspring participants. The mothers of 563 of these had been randomized to receive multiple prenatal ultrasound scans. The mean age of participants at follow-up was 20.0 years. There was no statistically significant difference between the two groups with regard to ocular biometric or visual outcomes, except for slightly higher intraocular pressure identified in individuals exposed to multiple ultrasound scans (P = 0.034). Although infants in the intensive-ultrasound arm were more likely to have birth weights in the lower quartiles, this was not reflected in adult eye development. Axial length, lens thickness, corneal curvature and thickness and optic cup to disc ratio (a risk factor for glaucomatous optic neuropathy) were not significantly influenced by the more frequent ultrasound protocol. CONCLUSIONS: Prior to this study, there was a paucity of safety data for ultrasound with regard to eye development. We found that frequent in-utero exposure to ultrasound, including B-mode imaging and the use of spectral Doppler mode from 18 weeks' gestation, had no significant impact on visual outcomes or ocular biometry.

A puzzle over several decades: eye anomalies with FRAS1 and STRA6 mutations in the same family.

Fraser syndrome (FS) and microphthalmia syndromic 9 (MCOPS9) are autosomal recessive conditions with distinct, and some overlapping features affecting the ocular, respiratory and cardiac systems. Mutations in FRAS1 and FREM2 occur in FS, and mutations in STRA6 occur in MCOPS9. We report two sibships, in the same family, where four deceased offspring had ocular, respiratory and cardiac abnormalities. Two sibs with microphthalmia had syndactyly and laryngeal stenosis, suggesting a clinical diagnosis of FS. Our results indicate that they were compound heterozygotes for novel FRAS1 mutations, p.Cys729Phe and p.Leu3813Pro. The other two sibs, first cousins to the first sib pair, had anophthalmia, lung hypoplasia and cardiac anomalies, suggesting a retrospective diagnosis of MCOPS9. Our results indicate compound heterozygous STRA6 mutations, a novel frameshift leading to p.Tyr18* and a p.Thr644Met mutation. The one surviving individual from these sibships is heterozygous for the p.Tyr18*STRA6 mutation and has bilateral ocular colobomata and microphthalmia. This work emphasises the need for careful phenotypic characterisation to determine genes for assessment in ocular syndromic conditions. It also indicates that heterozygous STRA6 mutations may rarely contribute to microphthalmia and coloboma.

A single EFEMP1 mutation associated with both Malattia Leventinese and Doyne honeycomb retinal dystrophy.

Malattia Leventinese (ML) and Doyne honeycomb retinal dystrophy (DHRD) refer to two autosomal dominant diseases characterized by yellow-white deposits known as drusen that accumulate beneath the retinal pigment epithelium (RPE). Both loci were mapped to chromosome 2p16-21 (refs 5,6) and this genetic interval has been subsequently narrowed. The importance of these diseases is due in large part to their close phenotypic similarity to age-related macular degeneration (AMD), a disorder with a strong genetic component that accounts for approximately 50% of registered blindness in the Western world. Just as in ML and DHRD, the early hallmark of AMD is the presence of drusen. Here we use a combination of positional and candidate gene methods to identify a single non-conservative mutation (Arg345Trp) in the gene EFEMP1 (for EGF-containing fibrillin-like extracellular matrix protein 1) in all families studied. This change was not present in 477 control individuals or in 494 patients with age-related macular degeneration. Identification of this mutation may aid in the development of an animal model for drusen, as well as in the identification of other genes involved in human macular degeneration.

Pediatric cataract, myopic astigmatism, familial exudative vitreoretinopathy and primary open-angle glaucoma co-segregating in a family.

PURPOSE: To describe an Australian pedigree of European descent with a variable autosomal dominant phenotype of: pediatric cortical cataract (CC), asymmetric myopia with astigmatism, familial exudative vitreoretinopathy (FEVR), and primary open-angle glaucoma (POAG). METHODS: Probands with CC, FEVR, and POAG were enrolled in three independent genetic eye studies in Tasmania. Genealogy confirmed these individuals were closely related and subsequent examination revealed 11 other family members with some or all of the associated disorders. RESULTS: Twelve individuals had CC thought to be of childhood onset, with one child demonstrating progressive lenticular opacification. One individual had severe retinal detachment while five others had dragged retinal vessels. Seven individuals had POAG. Seven individuals had myopia in at least one eye ≤-3 Diopters. DNA testing excluded mutations in myocilin, trabecular meshwork inducible glucocorticoid response (MYOC) and tetraspanin 12 (TSPAN12). Haplotype analysis excluded frizzled family receptor 4 (FZD4) and low density lipoprotein receptor-related protein 5 (LRP5), but only partly excluded EVR3. Multipoint linkage analysis revealed multiple chromosomal single-nucleotide polymorphisms (SNPs) of interest, but no statistically significant focal localization. CONCLUSIONS: This unusual clustering of ophthalmic diseases suggests a possible single genetic cause for an apparently new cataract syndrome. This family's clinical ocular features may reflect the interplay between retinal disease with lenticular changes and axial length in the development of myopia and glaucoma.

Olfactory dysfunction at six months after coronavirus disease 2019 infection.

OBJECTIVE: This study aimed to assess olfactory dysfunction in patients at six months after confirmed coronavirus disease 2019 infection. METHODS: Coronavirus disease 2019 positive patients were assessed six months following diagnosis. Patient data were recoded as part of the adapted International Severe Acute Respiratory and Emerging Infection Consortium Protocol. Olfactory dysfunction was assessed using the University of Pennsylvania Smell Identification Test. RESULTS: Fifty-six patients were included. At six months after coronavirus disease 2019 diagnosis, 64.3 per cent of patients (n = 36) were normosmic, 28.6 per cent (n = 16) had mild to moderate microsmia and 7 per cent (n = 4) had severe microsmia or anosmia. There was a statistically significant association between older age and olfactory dysfunction. Hospital or intensive care unit admission did not lead to worse olfactory outcomes compared to those managed in the out-patient setting. CONCLUSION: At six months after coronavirus disease 2019 diagnosis, approximately two-thirds of patients will be normosmic. This study is the first to describe six-month outcomes for post-coronavirus disease 2019 patients in terms of olfactory dysfunction.

Identification of a gene that causes primary open angle glaucoma.

Glaucoma is a major cause of blindness and is characterized by progressive degeneration of the optic nerve and is usually associated with elevated intraocular pressure. Analyses of sequence tagged site (STS) content and haplotype sharing between families affected with chromosome 1q-linked open angle glaucoma (GLC1A) were used to prioritize candidate genes for mutation screening. A gene encoding a trabecular meshwork protein (TIGR) mapped to the narrowest disease interval by STS content and radiation hybrid mapping. Thirteen glaucoma patients were found to have one of three mutations in this gene (3.9 percent of the population studied). One of these mutations was also found in a control individual (0.2 percent). Identification of these mutations will aid in early diagnosis, which is essential for optimal application of existing therapies.

Leber Hereditary Optic Neuropathy and Longitudinally Extensive Transverse Myelitis.

Leber Hereditary Optic Neuropathy is an inherited optic neuropathy caused by mitochondrial DNA point mutations leading to sudden, painless loss of vision. We report a case of an 8-year-old boy presenting with a radiological phenotype of longitudinally extensive transverse myelitis on a background of severe visual impairment secondary to Leber Hereditary Optic Neuropathy (LHON). He was found to have dual mitochondrial DNA mutations at 14484 (MTND6 gene) and 4160 (MTND1 gene) in a family with a severe form of LHON characterised by not only an unusually high penetrance of optic neuropathy, but also severe extra-ocular neurological complications. The m.14484T>C mutation is a common LHON mutation, but the m.4160T>C mutation is to our knowledge not reported outside this family and appears to drive the neurological manifestations. To our knowledge there have been no previous reports of spinal cord lesions in children with LHON.

The association between maternal smoking in pregnancy, other early life characteristics and childhood vision: the Twins Eye Study in Tasmania.

PURPOSE: To investigate the association between maternal smoking in pregnancy, early-life environment and childhood vision. METHODS: Twin and triplet children enrolled in the Twins Eye Study in Tasmania underwent a comprehensive ophthalmic examination and their parents/guardians retrospectively answered a questionnaire regarding crawling, walking and other measures. A subset of these twins was also in the Tasmanian Infant Health Survey, which prospectively collected data on antenatal smoking, gestation, birth weight and other factors. RESULTS: The mean age of the 346 individuals (172 multiple birth sets) at the time of examination was 9.25+/-2.4 years. Mean unaided visual acuity was 0.0 (6/6). The mean spherical equivalent was +0.87D, and decreased with increasing child age (p<0.01). A prospective analysis, accounting for birth set clustering and relevant confounders, showed increasing levels of maternal smoking in the third trimester was associated with poor stereoacuity on the Titmus test (worse (>) than 100'', p=0.05) and Lang test (p=0.001) and also with the presence of esotropia (p=0.02). These associations persisted after adjustment for infant postnatal smoke exposure at one month of age. Poor stereoacuity on Titmus stereo test circles was associated with late age of first crawling (RR=1.23 (1.06, 1.42) p=0.005 per month) and late age of first walking (RR 1.18 (1.05, 1.22) p=0.001 per month). CONCLUSIONS: Antenatal smoking was independently associated with poor stereovision and the presence of esotropia. Poor stereoacuity may be associated with delayed age at first crawling or walking.

The role of the Met98Lys optineurin variant in inherited optic nerve diseases.

AIMS: To investigate the role of the common OPTN Met98Lys variant as a risk allele in open-angle glaucoma (OAG), autosomal dominant optic atrophy (ADOA) and Leber's hereditary optic neuropathy (LHON). METHODS: The presence of the Met98Lys variant was determined in a total of 498 (128 with normal-tension glaucoma (NTG)) patients with OAG, 29 patients who had myocilin-related OAG, 101 patients from ADOA pedigrees, 157 patients from LHON pedigrees and 218 examined OAG age-matched normal controls. RESULTS: 17 of 218 (7.8%) controls had the Met98Lys variant. 28 (5.6%) patients with OAG were Met98Lys positive. More Met98Lys carriers were found in the NTG group than in the high-tension glaucoma (HTG) group (p = 0.033). However, no significant difference was observed between the NTG and control cohorts (p = 0.609). Two MYOC mutation carriers were found to have the variant. The variant was found in 1 of 10 pedigrees with ADOA and in 8 of 35 pedigrees with LHON. CONCLUSION: Data from this study do not support a strong role for the OPTN Met98Lys variant in glaucoma, ADOA or LHON. However, a weak association was observed of the variant with NTG compared with that with HTG. Meta-analysis of all published data on the variant and glaucoma confirmed that the association, although weak, is highly statistically significant in the cohort with glaucoma versus controls.

Nail-patella syndrome and its association with glaucoma: a review of eight families.

BACKGROUND: Nail-patella syndrome (NPS) is a rare autosomal dominant syndrome, characterised by dysplasia of the nails, patellae, elbows and iliac horns. Mutations in the LMX1B gene were found in four North American families in whom glaucoma cosegregated with NPS. AIMS: To investigate the association of glaucoma with NPS in Australian families and to determine how common NPS is in Australia. METHODS: One family with NPS and glaucoma was identified from the Glaucoma Inheritance Study in Tasmania. A further 18 index cases of NPS were identified from the genetics database for southeastern Australia. Eight of these pedigrees were available for comprehensive glaucoma examination on available family members. DNA was sequenced for mutations in LMX1B. RESULTS: In total, 52 living cases of NPS were identified suggesting a minimum prevalence of at least 1 in 100 000. 32 subjects from eight NPS pedigrees (four familial and four sporadic cases) were examined. 14 subjects had NPS alone. 4 subjects had NPS and glaucoma or ocular hypertension. Five pedigrees with NPS had a reported family history of glaucoma, although some of these people with glaucoma did not have NPS. LMX1B mutations were identified in 5 of the 8 index cases-three sporadic and two familial. Two of the six (33%) participants over 40 years of age had developed glaucoma, showing increased risk of glaucoma in NPS. CONCLUSION: Patients with NPS should be examined regularly for glaucoma. However, because the families with NPS are ascertained primarily from young probands or probands who are isolated cases, the exact level of risk is unclear.

Lack of association of p53 polymorphisms and haplotypes in high and normal tension open angle glaucoma.

BACKGROUND: The final common pathway for open angle glaucoma (OAG) is retinal ganglion cell apoptosis. Polymorphisms in p53, a major regulator of apoptosis, affect the efficiency of cell death induction. Association studies of p53 haplotypes and OAG have had conflicting results. OBJECTIVE: To examine the association between p53 haplotypes and OAG in a larger white population than in previous reports, and extend the analysis to normal tension glaucoma. METHODS: 345 unrelated people with OAG were recruited (283 subjects with high tension glaucoma and 62 with normal tension glaucoma) and compared with 178 age matched controls. Genomic DNA was analysed for the p53 codon 72 Arg/Pro polymorphism as well as for the presence or absence of a 16 bp intron 3 insertion. RESULTS: In this white cohort no association was found between glaucoma (high or normal tension) and either sequence variant or haplotype. CONCLUSIONS: The p53 codon 72 Arg/Pro polymorphism is not associated with age of onset or severity of glaucoma.

Emerging Mitochondrial Therapeutic Targets in Optic Neuropathies.

Optic neuropathies are an important cause of blindness worldwide. The study of the most common inherited mitochondrial optic neuropathies, Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (ADOA) has highlighted a fundamental role for mitochondrial function in the survival of the affected neuron-the retinal ganglion cell. A picture is now emerging that links mitochondrial dysfunction to optic nerve disease and other neurodegenerative processes. Insights gained from the peculiar susceptibility of retinal ganglion cells to mitochondrial dysfunction are likely to inform therapeutic development for glaucoma and other common neurodegenerative diseases of aging. Despite it being a fast-evolving field of research, a lack of access to human ocular tissues and limited animal models of mitochondrial disease have prevented direct retinal ganglion cell experimentation and delayed the development of efficient therapeutic strategies to prevent vision loss. Currently, there are no approved treatments for mitochondrial disease, including optic neuropathies caused by primary or secondary mitochondrial dysfunction. Recent advances in eye research have provided important insights into the molecular mechanisms that mediate pathogenesis, and new therapeutic strategies including gene correction approaches are currently being investigated. Here, we review the general principles of mitochondrial biology relevant to retinal ganglion cell function and provide an overview of the major optic neuropathies with mitochondrial involvement, LHON and ADOA, whilst highlighting the emerging link between mitochondrial dysfunction and glaucoma. The pharmacological strategies currently being trialed to improve mitochondrial dysfunction in these optic neuropathies are discussed in addition to emerging therapeutic approaches to preserve retinal ganglion cell function.

The telomere of human chromosome 1p contains at least two independent autosomal dominant congenital cataract genes.

AIMS: Multiple genetic causes of congenital cataract have been identified, both as a component of syndromes and in families that present with isolated congenital cataract. Linkage analysis was used to map the genetic locus in a six generation Australian family presenting with total congenital cataract. METHODS: Microsatellite markers located across all known autosomal dominant congenital cataract loci were genotyped in all recruited family members of the Tasmanian family. Both two point and multipoint linkage analysis were used to assess each locus under an autosomal dominant model. RESULTS: Significant linkage was detected at the telomere of the p arm of chromosome 1, with a maximum two point LOD of 4.21 at marker D1S507, a maximum multipoint exact LOD of 5.44, and an estimated location score of 5.61 at marker D1S507. Haplotype analysis places the gene inside a critical region between D1S228 and D1S199, a distance of approximately 6 megabases. The candidate gene PAX7 residing within the critical interval was excluded by direct sequencing in affected individuals. CONCLUSION: This is the third report of congenital cataract linkage to 1ptel. The critical region as defined by the shared haplotype in this family is clearly centromeric from the Volkmann cataract locus identified through study of a Danish family, indicating that two genes causing autosomal dominant congenital cataract map to the telomeric region of chromosome 1p.

Evaluation of the myocilin (MYOC) glaucoma gene in monkey and human steroid-induced ocular hypertension.

PURPOSE: Glucocorticoid-induced ocular hypertension (the steroid response) may result in optic nerve damage that very closely mimics the pathologic course of primary open angle glaucoma (POAG). In addition, patients with glaucoma and their relatives are much more likely to exhibit the steroid response than unaffected individuals, suggesting a potential link between the steroid response and POAG. Recently, the expression of a gene (MYOC) in the trabecular meshwork was shown to be steroid-induced. MYOC variations thought to be disease-causing also were found in 3% to 5% of POAG cases. The purpose of this study was to determine whether some variations in MYOC might be involved in steroid-induced ocular hypertension. METHODS: Seventy human steroid responders and 114 control subjects were screened for variations in the coding sequence and promoter of MYOC. Also, topical doses of dexamethasone (DEX) were administered to cynomolgus monkeys to determine their steroid responsiveness, and the MYOC orthologue was cloned from the cynomolgus monkey. RESULTS: Overall, 109 instances of 20 different sequence variations were identified in the human myocilin gene. However, only four of these (each observed in a single individual) met the study criteria for a possible phenotype-altering variation. Three of these were present in steroid responders and one in a control patient, a distribution that was not statistically significant (P: = 0.3). In addition, the allele frequency of a closely flanking marker was compared between the steroid responders and the control subjects, and no evidence for linkage disequilibrium was observed. Reproducible and reversible ocular hypertension was induced in approximately 40% of the monkeys treated with DEX, similar to that seen in man. Ten monkeys were screened for MYOC mutations with single-strand conformation polymorphism (SSCP) analysis. Overall, 37 instances of 13 different sequence variations were observed. Four of these changes met the study criteria for a possible phenotype-altering variation, and these were equally distributed between responder and nonresponder monkeys. CONCLUSIONS: This study identified no statistically significant evidence for a link between MYOC mutations and steroid-induced ocular hypertension.

Description of X-linked megalocornea with identification of the gene locus.

We studied the clinical appearance and inheritance in five families with X-linked megalocornea. Affected male subjects had corneal diameters between 13.0 and 16.5 mm. Arcus juvenilis, mosaic corneal dystrophy, and cataracts were found only in adult affected male subjects. No carrier female abnormality was identified. The gene locus for the X-linked form is in the region Xq12-q26. This is near the locus described for Aarskog (facial-digital-genital) syndrome, Xq12-13.

Accuracy and implications of a reported family history of glaucoma: experience from the Glaucoma Inheritance Study in Tasmania.

OBJECTIVES: To ascertain the prevalence of previously undiagnosed primary open-angle glaucoma (POAG) within 5 large POAG pedigrees and to evaluate the reliability of a reported family history of glaucoma within these pedigrees. METHODS: The Glaucoma Inheritance Study in Tasmania (GIST) identified several large adult POAG pedigrees. Intraocular pressure (IOP), optic disc stereophotography, and automated perimetry were performed on all adult pedigree members. Participants were classified as normal (IOP <22 mm Hg and normal optic disc and field); glaucoma suspect (normal field, but an IOP >/=22 mm Hg and/or suspicious optic disc); or POAG (field defect and glaucomatous optic disc). Some individuals with POAG had been previously diagnosed by their local ophthalmologist; others were diagnosed as a result of the GIST project. Family members with a prior diagnosis of POAG were asked to report if they were aware of any relatives with POAG. This reported family history was then directly compared with the actual pedigree (before the diagnosis of new cases) to calculate agreement. MAIN OUTCOME MEASURE: The rate of glaucoma in pedigrees and percentage of previously diagnosed glaucoma cases who were aware of the positive family history of POAG. RESULTS: Four hundred forty-two subjects (mean age, 54 years [range, 13-97 years]) from 5 pedigrees were examined: 316 subjects (71%) were normal, 47 (11%) were previously diagnosed with POAG, and 8 (2%) were previously diagnosed glaucoma suspects; 30 cases (7%) of POAG and 41 suspects (9%) were newly diagnosed as a direct result of the GIST examination. Of the 47 previously diagnosed POAG cases, 41 were questioned about their prior knowledge of any family history and 11 (27%) were unaware of their family history of POAG. CONCLUSIONS: Examination of all adult subjects from POAG families yields new cases. Even in large POAG pedigrees, 27% of previously diagnosed POAG patients were unaware of their positive family history. These findings suggest that a higher percentage of adult POAG may be inherited than hitherto reported. Arch Ophthalmol. 2000;118:900-904

The Taa1 restriction enzyme provides a simple means to identify the Q368STOP mutation of the myocilin gene in primary open angle glaucoma.

PURPOSE: To identify a rapid and reliable method to detect the Glutamine 368 STOP (Q368STOP) disease-predisposing allele of the myocilin gene associated with adult onset, primary, open-angle glaucoma. METHODS: Individuals with the Q368STOP mutation of the myocilin gene were identified from a cohort of primary open-angle glaucoma patients from Tasmania and subjected to Taa1 restriction digestion. RESULTS: In the Tasmanian family presented, screening with the Taa1 restriction enzyme successfully confirmed identification of all individuals with the Q368STOP mutation. CONCLUSIONS: The use of the Taa1 restriction enzyme offers a relatively simple, rapid, and reproducible technique that could be applied to detect the Q368STOP mutation of the myocilin gene.

Laboratory methods in ophthalmic genetics: obtaining DNA from patients.

DNA samples are the fundamental research substrate in genetics. Although methodology and cost-effectiveness in molecular biology have improved dramatically, collecting biological samples and extracting DNA continue to be expensive and time-consuming steps of genetic research. This article reviews the issues surrounding the choice of biological samples for methods of DNA extraction as well as the storage and transport of biological and DNA samples for genetic studies.

The 'GIST' score: ranking glaucoma for genetic studies. Glaucoma Inheritance Study of Tasmania.

The 'GIST' score was developed to facilitate linkage analysis of adult-onset primary open angle glaucoma (POAG) pedigrees in the Glaucoma Inheritance Study of Tasmania (GIST). Previous genetic linkage studies on juvenile open angle glaucoma pedigrees have relied upon an analysis of definitely affected individuals using the 'single best diagnosis' convention. Studies of adult-onset POAG have been complicated by limited numbers of unequivocally affected members identified even in very large pedigrees due to the later onset of the disease. Many members of the pedigree may have equivocal clinical features or are too young to show signs of the disease. The 'GIST score' is a numeric value between zero and one where zero is clinical certainty of absence of the disease and one is the definitive diagnosis of POAG. The score is developed by assigning relative weighting to key clinical features which results in a 'pedigee probability' of the diagnosis being present or absent in a member of a pedigree. Ranking of borderline and unaffected glaucoma subjects allows the laboratory more flexibility in the use of the members of the pedigree for linkage analysis. The score is not intended to have clinical usefulness in management of glaucoma.

The problem of overlapping glaucoma families in the Glaucoma Inheritance Study in Tasmania (GIST).

The Glaucoma Inheritance Study in Tasmania (GIST) is a population survey of Australia's island state, Tasmania (population 450,000). Its aim is to find families with autosomal dominant, adult-onset, primary open angle glaucoma (POAG) suitable for genetic linkage analysis. POAG is relatively common, affecting around 3% of the Australian population. By finding the large families with POAG and identifying all the descendants in a captive population, it is possible that there may be overlap of different glaucoma pedigrees. Three of the first thirteen families in the study were composed of overlapping pedigrees. In one GIST family, GTas3, there has been intermarriage with other pedigrees with glaucoma on five occasions. The possibility of multiple genotypes was also reinforced by the inability to determine a single glaucoma phenotype in this family. When finding large families of POAG for linkage analysis, researchers must be aware of the risk of affected individuals inheriting their gene from the alternate parent. Thus, the alternate parents or their families must be examined, especially if the phenotype is atypical for the rest of the family.