Abstract
Abstract: :
Purpose: To conduct extensive epidemiological, neuro-ophthalmological, psychophysical and DNA examinations on a newly discovered, very large pedigree Leber’s Hereditary Optic Neuropathy (LHON). Methods: A recently visually impaired 14 y.o., his mother and her two blinded brothers were examined and found to have LHON. Analysis of their blood mtDNA demonstrated this to be homoplasmic 11778, J-haplogroup. Their extensive family almost all lived in one rural area in Brazil, leading to an international field investigation. This team evaluated 273 of the 295 family members, conducting epidemiological interviews, comprehensive neuro-ophthalmological examinations, psychophysical and visual field studies, fundus photography and blood testing for both mitochondrial DNA analysis and also nuclear gene linkage analysis. Results: In 1861 a couple from Verona, Italy immigrated to rural Brazil. The subsequent generations demonstrated penetrance rates of 71%, 60%, 34%, 15% and 9%. Excluding the last generations, the percent males were 60%, 50%, 64%, 100%, 100%, and 100%. Age of onset varied from 10 to 64 years of age and current visual acuities varied from LP to 20/400. All tested subjects were homoplasmic 11778. Conclusion: Analysis of environmental risk factors and search for a nuclear modifying gene from this family will address the perplexing question of why only a fraction of genetically affected individuals manifest the disease. This fully described database may provide an excellent opportunity for future clinical trials of any purported neuro-protective agent.
Keywords: 487 neuro-ophthalmology: optic nerve • 625 visual impairment: neuro-ophthalmological disease • 475 mitochondria