Gyrate atrophy and choroidal neovascularization

Gyrate atrophy of the choroid and retina: Update on diagnosis and treatment

Gyrate atrophy of the choroid and retina (GACR) is a rare autosomal recessive disease characterised by elevated plasma ornithine levels due to deficiency of the enzyme ornithine aminotransferase (OAT). The accumulation of this amino acid in plasma leads to the development of patches of chorioretinal atrophy in the peripheral retina extending into the macular area. Patients usually present with night blindness followed by constriction of the visual field and, finally, decreased central vision and blindness. The disease is diagnosed by the presence of the characteristic clinical picture, the presence of hyperornithinaemia in plasma and the detection of mutations in the OAT enzyme gene. There is currently no effective gene therapy and the most common therapeutic intervention mainly involves dietary modifications with arginine restriction. This article aims to summarise the pathogenesis, clinical and diagnostic findings and treatment options in patients with GACR.

Macular neovascularization in inherited retinal diseases: A review

Inherited retinal diseases (IRDs) are the most common cause of blindness in working-age adults. Macular neovascularization (MNV) may be a presenting feature or occurs as a late-stage complication in several IRDs. We performed an extensive literature review on MNV associated with IRDs. MNV is a well-known complication of Sorsby fundus dystrophy and pseudoxanthoma elasticum. Those with late-onset Stargardt disease may masquerade as exudative age-related macular degeneration (AMD) when MNV is the presenting feature. Peripherinopathies may develop MNV that responds well to a short course of anti-vascular endothelial growth factor (anti-VEGF) therapy, while bestrophinopathies tend to develop MNV in the early stages of the disease without vision loss. Enhanced S-cone syndrome manifests type 3 MNV that typically regresses into a subfoveal fibrotic nodule. MNV is only a rare complication in choroideraemia and rod-cone dystrophies. Most IRD-related MNVs exhibit a favorable visual prognosis requiring less intensive regimens of anti-vascular endothelial growth factor therapy compared to age-related macular degeneration. We discuss the role of key imaging modalities in the diagnosis of MNV across a wide spectrum of IRDs and highlight the gaps in our knowledge with respect to the natural history and prognosis to pave the way for future directions of research.

Gyrate Atrophy of the Choroid and Retina: A Review

Gyrate atrophy (GA) of the choroid and retina is a rare autosomal recessive genetic condition characterized by elevation of the plasma level of the amino acid ornithine due to deficiency of the enzyme ornithine ketoacid aminotransferase. Accumulation of ornithine occurs in various body tissues but leads primarily to characteristic ophthalmic manifestations including myopia, cataract, progressive chorioretinal atrophy, and macular changes. Patients usually present with night blindness that starts in the first decade of life followed by visual field constriction and eventually diminution of the central visual acuity and blindness. The condition has been reported worldwide and its differential diagnosis is broad and includes choroideremia and retinitis pigmentosa. Treatment currently depends on life-long dietary modifications including restriction of the amino acid arginine in diet. This article describes in detail the pathogenesis, clinical features, multimodal imaging findings, and treatment options for GA of the choroid and retina and its complications.

Partial regression of foveoschisis following vitamin B6 supplementary therapy for gyrate atrophy in a Chinese girl

BACKGROUND

To report a case of genetically confirmed gyrate atrophy (GA) of choroid and retina, who showed partial regression of foveoschisis following vitamin B6 supplementary therapy.

CASE PRESENTATION

A 6-year-old Chinese girl complained about night blindness and progressive decreased vision in both eyes. Her best corrected visual acuity (BCVA) was 20/63 OD and 20/100 OS. Fundus examination showed bilateral multiple, sharply demarcated, scallop-shaped chorioretinal atrophy areas in the midperipheral and peripheral of the fundus. Spectral domain optical coherence tomography (SD-OCT) showed increased central macular thickness (CMT) with multiple intraretinal cystic spaces in the both eyes. There was no leakage or staining in the macular area in late phase of fluorescein angiography (FA). Blood tests confirmed hyperornithinemia and genetic analysis revealed two heterozygous mutations on ornithine aminotransferase (OAT) gene. Based on clinical presentation and genetic test, the patient was diagnosed as GA of the choroid and retina and further treated with vitamin B6 supplementary for three weeks. Her serum ornithine levels did not change but CMT on SD-OCT declined with partial regression of intraretinal cystic spaces. Then, the patient discontinued the drug because of severe muscle pain, and foveoschisis increased to initial level a month later.

CONCLUSIONS

Foveoschisis is a rare complication of GA. Vitamin B6 supplementation may alleviate foveoschisis, but its effort for reducing serum ornithine level might be limited. Potential drug adverse effects should be noted in pediatric patients.

Anti-VEGF and Retinal Dystrophies

The therapeutic approach based on anti-vascular endothelial growth factor (anti-VEGF) molecules can be used to treat two important complications of retinal dystrophies: choroidal neovascularization and macular edema. The macular involvement in retinal dystrophies can lead to further visual deterioration in patients at a young age and already affected by functional limitations. The study reports the effect of anti-VEGF treatment in several subforms of retinal dystrophies, critically discussing advantages and limitations.

Ultrawide field fluorescein angiogram in a family with gyrate atrophy and foveoschisis

Gyrate atrophy of choroid and retina is an autosomal recessive condition characterized by peripheral multiple sharp areas of chorioretinal atrophy which become confluent with age. Macula and central vision is typically involved late in the disease. Macular involvements such as cystoid macular edema, epimacular membrane, and choroidal neovascularization have been reported in gyrate atrophy. In this report, we present a family with diminished central vision presenting within 8 years of age. All of three siblings had typical peripheral chorioretinal atrophic lesions of gyrate atrophy and hyperornithinemia. On spectral domain optical coherence tomography, two of elder siblings showed macular edema. Hyporeflective spaces appeared to extend from outer nuclear layer to the inner nuclear layer level separated by multiple linear bridging elements in both eyes. Ultrawide field fluorescein angiogram (UWFI) even in late phase did not show any leak at macula suggesting foveoschisis. Foveoschisis in gyrate atrophy has not been reported before.

Arginine-Restricted Therapy Resistant Bilateral Macular Edema Associated with Gyrate Atrophy

Introduction. Gyrate atrophy is a rare genetical metabolic disorder affecting vision. Here, we report a 9-year-old boy with gyrate atrophy associated with bilateral macular edema at the time of diagnosis and the effect of long term metabolic control on macular edema. Case Presentation. A 9-year-old boy presented with a complaint of low visual acuity (best corrected visual acuity: 20/80 in both eyes, refractive error: −12.00 D). Dilated fundus examination revealed multiple bilateral, sharply defined, and scalloped chorioretinal atrophy areas in the midperipheral and peripheral zone. Spectral-domain optical coherence tomography revealed bilateral cystoid macular edema in both eyes. Serum ornithine level was high (622 μmol/L). An arginine-restricted diet reduced serum ornithine level (55 μmol/L). However, visual findings including macular edema remained unchanged in 2 years of follow-up. Conclusion. Arginine-restricted diet did not improve macular edema in our patient with gyrate atrophy. A more comprehensive understanding of the underlying factors for macular edema will lead to the development of effective therapies.

Intravitreal ranibizumab for choroidal neovascularization secondary to gyrate atrophy in a young patient: a multimodal imaging analysis

PURPOSE

To present a case of choroidal neovascularization (CNV) due to gyrate atrophy (GA) treated with intravitreal ranibizumab.

METHODS

A 35-year-old man presented with sudden loss of vision and central scotoma in the right eye, as well as progressive night vision deterioration over the past several years in both eyes. His best-corrected visual acuity (BCVA) was 6/60 in the right eye and 6/5 in the left eye. Funduscopy revealed bilateral confluent areas of chorioretinal atrophy and optical coherence tomography showed subretinal fluid consistent with CNV development in the right eye, which was confirmed by fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA). The left eye was normal. The patient had a family history of GA. Elevated levels of plasma ornithine were detected, establishing the diagnosis.

RESULTS

The patient received a regimen of 3 monthly off-label intravitreal ranibizumab injections in the right eye. At the 6-month follow-up, no subretinal fluid was noticed and BCVA was 6/48. No other injections were performed, but the patient was advised to start an arginine-restricted diet and take vitamin B6 (pyridoxine) 300 mg daily. The BCVA was preserved and chorioretinal atrophy had not progressed on funduscopy, FFA, or ICGA 1 year later.

CONCLUSIONS

Intravitreal ranibizumab can offer promising anatomical and functional results, maintaining visual acuity in patients with CNV secondary to GA, especially if used in combination with arginine-restricted diet and vitamin B6 supplementation.