Genetic diseases are caused by error in the DNA in sequences called “genes” or is an illness caused by abnormalities in genes or chromosomes. Most cells in the human body have 23 pairs of chromosomes, making a total of 46. There are four different types of genetic disorders: single-gene, multifactorial, chromosomal, and mitochondrial.

A genetic disorder is a disease caused by abnormalities in an individual’s genetic material genome. Genetic disorders can also be inherited. If a person carries the dominant gene for a disease, he or she will usually have the disease and each of the person’s children will have a 1 in 2 (50%) chance of inheriting the gene and getting the disease. Cancers is also caused by a mutation in a gene or group of genes in a person’s cells. These mutations can occur randomly or because of an environmental exposure such as cigarette smoke.

Chromosomes, distinct structures made up of DNA and protein, are located in the nucleus of each cell. Because chromosomes are carriers of genetic material, such abnormalities in chromosome structure as missing or extra copies or gross breaks and rejoining (translocations) can result in disease. Multifactorial, this type is also called as complex or polygenic. This type is caused by a combination of environmental factors and mutations in multiple genes.