Clinical, biochemical and molecular analysis in a cohort of individuals with gyrate atrophy.

BACKGROUND: Gyrate atrophy of the choroid and retina is a rare autosomal recessive metabolic disorder caused by biallelic variants in the OAT gene, encoding the enzyme ornithine δ-aminotransferase. Impaired enzymatic activity leads to systemic hyperornithinaemia, which in turn underlies progressive chorioretinal degeneration. In this study, we describe the clinical and molecular findings in a cohort of individuals with gyrate atrophy. METHODS: Study participants were recruited through a tertiary UK clinical ophthalmic genetic service. All cases had a biochemical and molecular diagnosis of gyrate atrophy. Retrospective phenotypic and biochemical data were collected using electronic healthcare records. RESULTS: 18 affected individuals from 12 families (8 male, 10 female) met the study inclusion criteria. The median age at diagnosis was 8 years (range 10 months - 33 years) and all cases had hyperornithinaemia (median: 800 micromoles/L; range: 458-1244 micromoles/L). Common features at presentation included high myopia (10/18) and nyctalopia (5/18). Ophthalmic findings were present in all study participants who were above the age of 6 years. One third of patients had co-existing macular oedema and two thirds developed pre-senile cataracts. Compliance with dietary modifications was suboptimal in most cases. A subset of participants had extraocular features including a trend towards reduced fat-free mass and developmental delay. CONCLUSIONS: Our findings highlight the importance of multidisciplinary care in families with gyrate atrophy. Secondary ophthalmic complications such as macular oedema and cataract formation are common. Management of affected individuals remains challenging due to the highly restrictive nature of the recommended diet and the limited evidence-base for current strategies.

Optical coherence tomography angiography: a review of the current literature.

This narrative review presents a comprehensive examination of optical coherence tomography angiography (OCTA), a non-invasive retinal vascular imaging technology, as reported in the existing literature. Building on the coherence tomography principles of standard OCT, OCTA further delineates the retinal vascular system, thus offering an advanced alternative to conventional dye-based imaging. OCTA provides high-resolution visualisation of both the superficial and deep capillary networks, an achievement previously unattainable. However, image quality may be compromised by factors such as motion artefacts or media opacities, potentially limiting the utility of OCTA in certain patient cohorts. Despite these limitations, OCTA has various potential clinical applications in managing retinal and choroidal vascular diseases. Still, given its considerable cost implications relative to current modalities, further research is warranted to justify its broader application in clinical practice.

Post-operative Horner's Syndrome Following Total Thyroidectomy: A Case Report.

The oculosympathetic chain is a three-neuron pathway responsible for sympathetic innervation to the eye, which follows a complex anatomical course through the head and neck. Neck surgery may cause injury to this pathway, causing loss of sympathetic innervation producing the eponymous Horner's syndrome (ipsilateral ptosis, miosis and anhidrosis), but this is rare in the reported literature. We present the case of a 23-year-old female who underwent total thyroidectomy for a right-sided, metastatic papillary thyroid carcinoma. Following surgery, in the immediate postoperative period, she was noted to have unilateral ptosis and miosis. This patient was assessed by an ophthalmologist due to persistent unilateral ocular symptoms following thyroidectomy. She was subsequently diagnosed with right-sided Horner's syndrome. The diagnosis was confirmed following the observed reversal of her ocular symptoms using apraclonidine 1% minims. The management of Horner's syndrome following thyroidectomy is conservative if no evidence of compressive hematoma or seroma is identified as in this case. The patient was followed up at six weeks following thyroidectomy and a partial improvement in ptosis was noted. The patient also reported blurred vision secondary to increased refractive error due to reduced pupillary function in her right eye. Prognosticating recovery from Horner's syndrome following thyroidectomy is challenging due to limited evidence. Horner's syndrome as a possible complication of thyroidectomy should be counselled to patients pre-operatively. A residual deficit from Horner's syndrome may cause functional impairment in addition to the poor cosmetic outcome.