Novel biallelic USH2A variants in a patient with usher syndrome type IIA- a case report.

BACKGROUND: Usher Syndrome is the commonest cause of inherited blindness and deafness. The condition is clinically and genetically heterogeneous, with no current treatment. We report a case carrying novel biallelic variants in USH2A causing progressive early adolescent onset visual and hearing impairment consistent with Usher Syndrome Type IIA. CASE PRESENTATION: Our patient presented at age 13 with progressive visual field loss and hearing loss, associated with early onset of cataract in her 40s requiring lens extraction. Now 52 years old, latest best corrected visual acuity (BCVA) stands at Logmar Right Eye (RE) 0.8 and Left Eye (LE) 0.2, with significantly constricted visual fields bilaterally. She was registered partially sighted age 46. Clinical and molecular genetic assessment of the proband was consistent with a diagnosis of Usher Syndrome Type IIA. Genetic testing identified two novel USH2A variants, resulting in the premature termination codon p.Leu30Ter and a missense mutation p.Cys3251Tyr. Segregation analysis confirmed that these variants were biallelic in the affected case. Comprehensive in silico analysis confirmed that these mutations are the probable cause of Usher Syndrome Type IIA in this individual. CONCLUSIONS: The identification of novel mutations in USH2A increases the spectrum of genetic variations that lead to Usher Syndrome, aiding genetic diagnosis, assessment of patient prognosis, and emphasising the importance of genetic testing to identify new mutations in patients with undiagnosed progressive visual loss.

Ten-year mortality and long-term visual acuity outcomes in patients with exudative age-related macular degeneration treated with intravitreal anti-vascular endothelial growth factor injections.

PURPOSE: There are limited real-world data on long-term mortality and visual outcomes in patients treated with anti-vascular endothelial growth factor (VEGF) for exudative age-related macular degeneration (exudative AMD). We assessed 10-year mortality and clinical outcomes in exudative AMD patients treated with intravitreal therapy (IVT) anti-VEGF injections on a pro-re-nata (PRN) regime following a standard loading regime. METHODS: Retrospective cohort study of the first 216 exudative AMD patients receiving IVT anti-VEGF for exudative AMD at a public tertiary referral hospital in Scotland. Main outcome measures were mortality, cause of death and best-corrected visual acuity (BCVA). RESULTS: A total of 216 patients were included. Mean age at presentation was 79.1 years [standard deviation (SD) 6.9]. Mean follow-up duration was 6.6 years (SD 3.2) during which there was a mean 24.3 Early Treatment Diabetic Retinopathy Study (ETDRS) letter loss in BCVA (P < 0.0001). Patients received a mean of 2.2 (SD 1.8) injections per year of follow-up. Overall, 52.6% (113/216) died during the period studied. Observed annual mortality incidence risk was 6.5% (SD 3.1) and was found to be significantly lower (P = 0.0064) than the expected annual death incidence risk (9.6%, SD 1.5) based on age and sex standardised Scottish mortality risk. The most common causes of death were malignancies (21.3%) and infection (20.0%). CONCLUSIONS: This study highlights the relatively good long-term prognosis in vision and mortality in exudative AMD treated with a PRN regime in the real world. Although the majority lost vision, the rate of decline was significantly slower than that which would have been experienced in the pre-anti-VEGF era and reassuringly standardised mortality risk was lower than the national average.

A missense variant in FGD6 confers increased risk of polypoidal choroidal vasculopathy.

Polypoidal choroidal vasculopathy (PCV), a subtype of 'wet' age-related macular degeneration (AMD), constitutes up to 55% of cases of wet AMD in Asian patients. In contrast to the choroidal neovascularization (CNV) subtype, the genetic risk factors for PCV are relatively unknown. Exome sequencing analysis of a Han Chinese cohort followed by replication in four independent cohorts identified a rare c.986A>G (p.Lys329Arg) variant in the FGD6 gene as significantly associated with PCV (P = 2.19 × 10(-16), odds ratio (OR) = 2.12) but not with CNV (P = 0.26, OR = 1.13). The intracellular localization of FGD6-Arg329 is distinct from that of FGD6-Lys329. In vitro, FGD6 could regulate proangiogenic activity, and oxidized phospholipids increased expression of FGD6. FGD6-Arg329 promoted more abnormal vessel development in the mouse retina than FGD6-Lys329. Collectively, our data suggest that oxidized phospholipids and FGD6-Arg329 might act synergistically to increase susceptibility to PCV.

New loci and coding variants confer risk for age-related macular degeneration in East Asians.

Age-related macular degeneration (AMD) is a major cause of blindness, but presents differently in Europeans and Asians. Here, we perform a genome-wide and exome-wide association study on 2,119 patients with exudative AMD and 5,691 controls, with independent replication in 4,226 patients and 10,289 controls, all of East Asian descent, as part of The Genetics of AMD in Asians (GAMA) Consortium. We find a strong association between CETP Asp442Gly (rs2303790), an East Asian-specific mutation, and increased risk of AMD (odds ratio (OR)=1.70, P=5.60 × 10(-22)). The AMD risk allele (442Gly), known to protect from coronary heart disease, increases HDL cholesterol levels by 0.17 mmol l(-1) (P=5.82 × 10(-21)) in East Asians (n=7,102). We also identify three novel AMD loci: C6orf223 Ala231Ala (OR=0.78, P=6.19 × 10(-18)), SLC44A4 Asp47Val (OR=1.27, P=1.08 × 10(-11)) and FGD6 Gln257Arg (OR=0.87, P=2.85 × 10(-8)). Our findings suggest that some of the genetic loci conferring AMD susceptibility in East Asians are shared with Europeans, yet AMD in East Asians may also have a distinct genetic signature.

Toll-like receptor 3 polymorphism rs3775291 is not associated with choroidal neovascularization or polypoidal choroidal vasculopathy in Chinese subjects.

BACKGROUND/AIMS: Age-related macular degeneration (AMD) is a leading cause of visual impairment. A single-nucleotide polymorphism (SNP; rs3775291) in the Toll-like receptor 3 (TLR3) gene has recently been implicated in the pathogenesis of AMD in Caucasian populations. The aim of this study was to examine this association in Chinese persons with choroidal neovascularization (CNV) secondary to AMD and polypoidal choroidal vasculopathy (PCV). METHODS: This was an observational cross-sectional study in Singapore. Study subjects were of Chinese ethnicity and included patients with exudative maculopathy and normal control subjects. The diagnoses of CNV and PCV were made based on fundus examination, fluorescein angiography and indocyanine green angiography findings. Genomic DNA was extracted, and genotypes were determined by bidirectional DNA sequencing. We compared the allele and genotype frequencies between subjects with CNV and PCV with controls using the software PLINK. RESULTS: A total of 246 subjects with exudative maculopathy (consisting of 126 with CNV and 120 with PCV) and 274 normal control subjects were recruited. The distribution of rs3775291 SNP genotypes for CNV and PCV was not significantly different from that for normal controls. CONCLUSION: This study indicates that the TLR3 rs3775291 gene polymorphism is not associated with CNV and PCV in Singaporean Chinese patients.

Polypoidal choroidal vasculopathy and neovascular age-related macular degeneration: same or different disease?

Neovascular age-related macular degeneration (nAMD) is the commonest cause of severe visual impairment in older adults in Caucasian white populations. Polypoidal choroidal vasculopathy (PCV) has been described as a separate clinical entity differing from nAMD and other macular diseases associated with subretinal neovascularization. It remains controversial as to whether or not PCV represents a sub-type of nAMD. This article summarizes the current literature on the clinical, pathophysiological and epidemiological features and treatment responses of PCV and compares this condition to nAMD. Patients with PCV are younger and more likely Asians, and eyes with PCV lack drusen, often present with serosanguinous maculopathy or hemorrhagic pigment epithelial detachment, and have differing responses to photodynamic therapy and anti-vascular endothelial growth factor (VEGF) agents. There are also significant differences in angiographic and optical coherence tomography features between PCV and nAMD. Histopathological studies suggest differences in the anatomical details of the associated vascular abnormalities in the retina and choroids and the relative role of VEGF. There is emerging evidence of common molecular genetic determinants involving complement pathway and common environmental risk factors (e.g. smoking). Such information could further assist clinicians involved in the care of elderly patients with these conditions.

Nystagmus secondary to drug exposure in utero.

AIM: To report the occurrence of nystagmus in children exposed to opiates and/or benzodiazepines during pregnancy, and to describe the associated ocular and systemic findings. METHODS: Clinical examination and casenote review of 14 children with nystagmus whose mothers had misused opiates and/or benzodiazepines during pregnancy. RESULTS: Twelve children were exposed to opiates during pregnancy, of whom nine had also been exposed to benzodiazepines. Two children were exposed to benzodiazepines alone. In the primary position, the nystagmus was a fine horizontal pendular type in 10 (71.4%) children and was a fine horizontal jerk nystagmus in the other 4 (28.6%) children. The onset of the nystagmus probably occurred in the first 6 months of life in all cases. The mean binocular best-corrected logarithm of the minimum angle of resolution visual acuity was 0.59 (20/80). Electroretinogram and visual evoked potential examinations were found to be normal in the three children tested. Nine (64.3%) children had developmental delay and at least 7 (50%) had delayed visual maturation. Six children had microcephaly and two had bilateral optic nerve hypoplasia. None of the children had a specific neurological diagnosis or seizure disorder. CONCLUSION: This study strongly supports a teratogenic association between exposure to controlled drugs in utero and infantile nystagmus. Furthermore, the nystagmus and associated clinical features seem to be particularly associated with combined use of opiates and benzodiazepines. Exposure to opiates and/or benzodiazepines during pregnancy should be considered in the differential diagnosis of infantile nystagmus.