Since 1976, the ESCI Award for Excellence in Clinical Science (formerly called the Mack-Forster Award) has been awarded annually to a European scientist under the age of 45, in recognition of a significant and original work within the area of clinical science, as well as in recognition of scientific leadership. In 1998, the recipient of the ESCI Award for Excellence in Clinical Science was Anthony H. V. Schapira, Professor of Clinical Neurosciences, Head of the Department of Clinical Neurosciences, Chairman of the Division of Clinical Sciences at the Royal Free Hospital School of Medicine in London, and Professor of Clinical Neurology at the University Department of Clinical Neurology at Queen Square. Dr Schapira is a graduate of London University and the Westminster Medical School. He received his neurology training at the University of London Hospitals and at the National Hospital at Queen Square. Since the end of his medical training Dr Schapira has been interested in the role of mitochondrial dysfunction in human diseases. His early work focused on defining the molecular and biochemical defects in mitochondrial disorders responsible for myopathies, and his first major paper on mitochondrial myopathies was published in the Lancet in 1988, the year he became an MD. Two years later, in a paper published in the New England Journal of Medicine, Dr Schapira showed that mitochondrial myopathies can be caused by a defect of mitochondrial protein transport, and this was the first description of a human disorder caused by such a defect. Subsequently, Dr Schapira focused on the mitochondrial DNA depletion syndrome. Using genomic complementation techniques, he was able to show that the genetic defect, which is responsible for this disease, resides not in the mitochondria but in the nucleus, and that it leads to abnormal mitochondrial DNA replication. This finding demonstrates that an interaction between nuclear and mitochondrial DNA is necessary for normal development of mitochondrial respiratory chain complexes Fig 1. Figure A. H. V. Schapira The most important work of Dr Schapira is probably that which demonstrated the involvement of mitochondrial dysfunction in the pathogenesis of neurodegenerative disorders. Dr Schapira was the very first person to show that patients with Parkinson's disease have a specific complex I deficiency, and that this deficiency is selective for the substansia nigra within the central nervous system. Thereafter, he obtained evidence suggesting that, in some patients, this defect could be due to a primary mitochondrial DNA defect. This mitochondrial defect might represent a fundamental defect in Parkinson's disease, and its importance is illustrated by the fact that mitochondrial inhibitors can induce apoptosis or necrosis in dopaminergic cells, in a concentration-dependent manner. Dr Schapira has also studied another neurodegenerative disorder, Huntington's disease. He has identified a severe mitochondrial defect in the caudate nucleus, and he has obtained evidence suggesting that this defect could be part of a common biochemical pathway initiated by the genomic mutation (an expanded triplet repeat in the huntington gene), and in which excitotoxicity may participate. The clinical relevance of this seminal work on Parkinson's disease and Huntington's disease is illustrated by the fact that it led to the initiation of international clinical trials, which are now in progress. Dr Schapira's work has already been recognised by numerous investigation awards, by many invitations to speak throughout the world, and by the fact that he is co-editor of two standard textbooks on mitochondrial diseases.