Genetic Disease

A genetic disease or disorder is any disease that is caused by an abnormality in an individual's genome. The abnormality can range from minuscule to major -- from a discrete mutation in a single base in the DNA of a single gene to a gross chromosome abnormality involving the addition or subtraction of an entire chromosome or set of chromosomes.

Why do we have genes that cause genetic disorders?

Many genes are named for the disorders to which they have been linked. This can be very confusing. For example, the gene associated with hereditary hemochromatosis is called the “hemochromatosis gene.” This name implies that the gene exists for the sole purpose of causing disease, which of course is not the case. The normal function of a gene is to encode a protein, not cause illness. Disease occurs when genes are unable to work properly. The hemochromatosis gene actually codes for a membrane protein that works with other proteins to regulate iron absorption in cells. Like other single-gene disorders, hemochromatosis occurs when a gene is mutated in a way that prevents it from encoding a normal, functional protein product. See hereditary hemochromatosis disorder and gene profiles for more information about this condition.

People who have one recessive gene for a disease are called carriers, and they don't usually have the disease because they have a normal gene of that pair that can do the job. When two carriers have a child together, however, the child has a 1 in 4 (25%) chance of getting the disease gene from both parents, which results in the child having the disease. Cystic fibrosis (a lung disease), sickle cell anemia (a blood disease), and Tay-Sachs disease (which causes nervous system problems) are caused by recessive disease genes from both parents coming together in a child.

Genetic diseases can be inherited and are mutations in the germ cells of the body—the cells involved in passing genetic information from parents to offspring. Genetic diseases can also result from changes in DNA in somatic cells, or cells in the body that are not germ cells.

Some genetic diseases are called Mendelian disorders—they are caused by mutations that occur in the DNA sequence of a single gene. These are usually rare diseases; some examples are Huntington’s disease and cystic fibrosis. Many genetic diseases are multifactorial—they are caused by mutations in several genes compounded by environmental factors. Some examples of these are heart disease, cancer, and diabetes.

Children and adults with a rare genetic disease have multiple needs to address: health concerns, primarily, but others as well. As a service to the global Jewish community, Mazornet.com is committed to gathering and compiling data about Jewish genetic disorders. More importantly, Mazornet.com’s mission is to serve as the ultimate information resource by surfacing areas of assistance online and in the real world. It is not Mazornet.com’s intent to choose resources, but rather to make support information and resources of any kind available to the people and to the families afflicted by these diseases.