Recent work has led to the genetic understanding of an increasingly large number of neurological disorders that affect the nervous system of children, resulting in symptoms such as mental retardation, autistic symptoms, cerebral palsy, or seizures. These conditions are extremely heterogeneous genetically, meaning that large numbers of genes appear to be essential for normal nervous system function, and that mutations in different genes can sometimes cause very similar symptoms. The larger family size, recent population growth, and unique ancestry of populations in the Gulf region provide special opportunities for understanding the causes of childhood neurological disease both here and throughout the world. Here I review some recent developments, and discuss their impact on therapy.

For more than a century after the description of Huntington's Disease (HD), an inherited neurodegenerative disorder, by George Huntington, a physician on Long Island New York, research into the affliction concentrated on clinical and neuropathological correlates, trying to work backwards from these phenotypes to crucial steps earlier in the disease pathway. These efforts provided excellent clinical and pathological descriptions, and supplied chemical models in rodents, but working backwards from the ultimate disease phenotype did not identify definitive, causative biochemical steps in the disease process or provide a rational route to an effective therapy. In 1983, an alternative approach emerged, aimed at studying pathogenesis from its starting point, the HD gene, rather than from its endpoint, neuronal dysfunction and loss. This paradigm, which I term the Genetic Research Cycle, has acted as a model for similar investigations in a wide range of neurological disorders, leading to better diagnosis and patient management, deeper understanding of pathogenesis, and routes for developing rational, effective treatments.