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International Foundation for Optic Nerve Disease

P. O. Box 777, Cornwall NY 12518, USA
Email: IFOND@aol.com
Phone [g voice]: 6572067250

 

Summary of LHON Field Investigations made possible by IFOND support:

Brazil I- Brazil V


Alfredo A. Sadun, MD, PhD; July, 2006


In 2001, I was privileged to lead a large international team to rural Brazil for the first of five yearly field investigations for the understanding and cure of Leber's Hereditary Optic Neuropathy (LHON). LHON is tragic in that nothing can be currently done to prevent this catastrophic loss of vision that destroys the two optic nerves of young adults in the prime of their lives.


A great breakthrough occurred when, in the summer of 2001, we identified the world's largest pedigree living in a rural area of Brazil. This family contains about 332 subjects who are either affected with, carriers of or members of the nuclear family with LHON. Each year a large number of international and Brazilian specialists gather for very sophisticated testing and studies of these patients. This very intense period of investigation then leads to a number of new understandings that are presented and published in the world's literature.


The following is a simple summary of each of these yearly investigations, their objectives and accomplishments.


Brazil I - 2001: Epidemiological studies and gene linkage analysis were initiated to determine the genetics and epigenetics of this pedigree.


Brazil II - 2002: We brought to Brazil, sophisticated equipment and world experts in the use of this equipment for psychophysical examinations of members of this pedigree to complement the comprehensive neuro-ophthalmological examinations.


Brazil III - 2003: We developed novel testing including cutting edge psychophysical evaluation techniques such as multifocal ERGs. We also investigated a number of new serological measures of oxidative stress.


At the end of these trips several conclusions had been reached and published. We concluded that there were subclinical manifestations of the disease that allowed us to follow chronic progression in non-affected carriers. For example, we found alterations in color vision, contrast sensitivity and noted retinal nerve fiber layer swelling.


Brazil IV (2004) also brought new revelations. In particular we found that we could follow the progression of LHON in carriers, and that there were serological changes that were abnormal. Most remarkably, two patients, that were without visual complaint showed progression of these subclinical changes and both patients lost vision in a fairly classical way. However, these patients also demonstrated a delay before involvement of the second eye and a milder loss of vision in the second eye that may have reflected the effects of brimonidine drops that were administered to the second eye before it became involved. Hence, although we haven't yet found a cure or even an effective therapy for the visual loss in LHON, we have found clinical measures that help predict who will lose vision and, furthermore, confirmation through a proof of principle, that our proposed mechanism of pathology, is likely to be correct.


Brazil V (2005) brought an even larger number of scientists and clinicians. This trip pursued these objectives:

  1. Maintain the infrastructure of clinics and local volunteers who are available to examine the members of this pedigree year round and to respond to any carriers who develop visual loss.

  2. Arrange for specialized necropsy of eye, brain and peripheral nerve tissues for some members of the family that may die during the next few years.

  3. Further refine the validity and reliability of several quantitative psychophysical tests.

  4. Apply new technology in the form of Optical Coherence Tomography.

  5. Obtain serum levels of NSE in a larger cohort of the pedigree.

  6. Further apply the most sensitive new electophysiological measures.

  7. Attempt new modalities of therapy such as long wavelength (670um) light to modulate mitochondrial activity in carriers.

  8. Continue the longitudinal study of carriers both to document conversion to affected status and to see which parameters may predict such conversion.

  9. Compare the results of various parameters with each other.

  10. Educate and support members of the pedigree.



To date, about ten publications document the new insights and discoveries made by our five field investigations to rural Brazil to study LHON. Textbooks and book chapters are just now changing the description of LHON in light of these new studies. Great progress has been made, understandings established such that we now understand the basic biological cause of this disease.


About 15 international and renown scientists are joined by another 20 Brazilian volunteer scientists and physicians in this enterprise. They gladly donate several weeks each year for the privilege of working at the cutting edge of the science and hoping to soon bring about the successful management of this blinding disorder. All of these trips were largely subsidized by IFOND. We, the investigators, the study patients and all other patients around the world with LHON, and, most particularly the next generation who will inherit LHON but not go blind, are most grateful.


We thank the many supporters of IFOND who have made these groundbreaking investigations possible.

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The International Foundation for Optic Nerve Disease
P. O. Box 777, Cornwall NY 12518, USA.
Phone [g voice]: 6572067250
Email: ifond@aol.com
Web site: http://www.ifond.org/


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