GENETIC DISORDER - BREAST CANCER A genetic disorder is any disease that is caused by abnormalities in genetic material, otherwise known as a person's genome (Hecht and Hecht, 2008; Office of Biological and Environmental Research, 2008). There are four types of genetic disorders: single-gene or monogenic where the abnormalities are in just one gene; multifactorial also called complex or polygenic, where abnormalities are found in multiple genes; chromosomal which means there are abnormalities in the chromosome, which carries the genetic material through the body; and mitochondrial inheritance, which is "caused by mutations in the nonchromosomal DNA of mitochondria" (Hecht and Hecht, 2008; Office of Biological and Environmental Research, 2008). This last one is very rare. There are more than 6,000 single-gene diseases, all of which are inherited (Hecht and Hecht, 2008). Some examples include sickle-cell anemia and cystic fibrosis (Office of Biological and Environmental Research, 2008). Multifactorial genetic diseases are caused by both heredity and the environment (Office of Biological and Environmental Research, 2008). Examples of multifactorial genetic diseases include heart disease, high blood pressure, arthritis and Alzheimer's disease (Hecht and Hecht, 2008). Examples of chromosomal genetic disorders include Down's syndrome and trisomy (Hecht and Hecht, 2008; Office of Biological and Environmental Research, 2008). A disease may be genetic but not hereditary. For example, breast cancer is a genetic disease. Scientists know that: "different genes that influence breast cancer susceptibility have been found on chromosomes 6, 11, 13, 14, 15, 17, and 22" (Hecht and Hecht, 2008). Breast cancer in both men and women is a genetic disorder but it is not necessaril