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Show Poster 162 The Epidemiology and Clinical Characteristics of Leber Hereditary Optic Neuropathy (LHON) in a Canadian Province. Colten Wendel1, Jiyoung Hwang1, Andre Mattman1, Hilary Vallance1, Claire Sheldon1 1 University of British Columbia, Vancouver, BC, Canada Introduction: With promising clinical trials, there is a need for an accurate understanding of the epidemiology of LHON. This study aims to estimate the prevalence and describe the clinical presentation of LHON in a Canadian Province. Methods: In this province, all molecular testing for mitochondrial disorders is co-ordinated and documented through the Provincial Biochemical Genetics Laboratory. In a retrospective study, all subjects diagnosed with LHON between 1996-2016 were collated and clinical information was gathered. Results: We identified 44 subjects with genetically-confirmed LHON. In the mid-year point of the study, there were 3,444,285 people <65 years old. The minimum point prevalence for LHON within this population was 1.28 per 100,000 (95% CI 1.12-1.73 per 100,000). This is lower than seen in England and comparable to prevalence rates in Finland and Denmark. Heteroplasmy was present in 9% of cases. Of the 44 cases, 41 were LHON primary mutations (11778G>A, 14484T>C, and 3460G>A). Overall, subjects were 55% male, with an average age of symptom onset at 27.4 +/- 4.8 years. For those with symptomatic vision loss, the average time between fellow eye involvement was 2.7 +/- 0.9 months. The average wait time from initial onset of visual loss to diagnostic testing was 1.3 +/- 0.7 years. One patient was treated with idebenone. Clinical phenotype varied: there were 3 patients with MS-like illness with symptomatic white matter lesions, 2 with dystonia and 1 with a cardiac conduction abnormality. Finally, seven subjects experienced partial recovery of visual loss. Conclusions: Epidemiological information can help inform the patient population that may benefit from new treatments. In this province, nearly 2 in 50,000 people possess LHON mt DNA mutations, although there is a significant delay in diagnosis. Mechanisms to improve access to mitochondrial DNA testing is an important consideration in future healthcare policies given the emerging therapies for LHON. References: 1. Chinnery et al., "The Epidemiology of Leber Hereditary Optic Neuropathy in the North East of England." Am. J. Human Genetics, 98, Page 1271, 2016. 2. Man, Turnbull, Chinnery., "Leber hereditary optic neuropathy." J. Med Genetics, 53, 493, 2016. 3. Nikoskelainen et al., "Epidemiology and penetrance of Leber hereditary optic neuropathy in Finland." Eur. J. Human Genetics, 15, 1079-1089, 2007. 4. Norby et al., "Primary pathogenic mtDNA mutations in multigeneration pedigrees with Leber hereditary optic neuropathy." Am. J. Human Genetics, 59, 481-5, 1996. Keywords: Genetic Disease, Diagnostic Tests (ERG, VER, OCT, HRT, mfERG, etc) Eyelid & adnexal disease, Optic neuropathy, Neuroophth & systyemic disease ( eg. MS, MG, thyroid) Financial Disclosures: The authors had no disclosures. Grant Support: None. 2018 Annual Meeting | 306 |
