Huntington’s disease is caused by an inherited genetic defect of a single abnormal gene. Every child of a parent with HD has a 50 percent chance of inheriting the gene, and many do not know they have it until after they’ve procreated and passed the gene along to their own children. Children who do not inherit the abnormal gene will not pass it along to subsequent generations, but those who do will inevitably develop the disease. Genetic testing can let a person know whether he or she has the mutated gene before symptoms appear.
Scientists do not fully understand how HD causes cell death. Areas of research interest include the overstimulation of cells by natural chemicals in the brain, defective energy metabolism, oxidative stress and factors associated with natural chemical substances that may prevent cell death in the body.