Whether or not a person develops Huntington's Disease depends entirely on genetics. If you need to brush up on your genetics, here is a fairly quick overview. In the nucleus of each cell in the human body, there are 46 chromosomes. Sequences of a few nitrogenous bases in certain orders code for amino acids. There are 20 different amino acids from which proteins are composed.
Chromosomes contain our DNA or genetic makeup.
An easy way to understand DNA is to think of it as the blueprints of our body. DNA is divided into chunks called genes. Different genes contain the blueprints for different organs, bones, blood vessels, etc. In other words, the sperm and the ovum each contain 23 chromosomes. The sperm and the ovum, known as gametes, are also called haploid cells because they contain only half of the genetic material required to make a person.