And while Parkinson's appears to run in some families, no gene has ever been identified to suggest that it is hereditary. My belief is that toxic injury to key brain centers controlling movement may be responsible. Degeneration of these cells results in a reduction in levels of dopamine and upsets the balance between dopamine and another brain chemical, acetylcholine. The most familiar signs of the disease are tremors like the ones you mention. Other signs are a generalized slowness of movement, stiff limbs and problems with balance or gait.
Mental function can deteriorate in advanced cases.
There's no cure for Parkinson's, but it can often be successfully treated. Standard treatments include a variety of drugs, including L-Dopa and Sinemet, as well as surgical procedures that, by destroying tiny areas of brain tissue, bring the worst tremors under control. Experimental methods include fetal tissue grafts into the brain to increase dopamine levels in depleted areas. I do not know of alternative therapies that are specific for Parkinson's disease, but many approaches can help reduce symptoms. Stress reduction is a must, because tremors always worsen when patients are stressed.