What is a rare genetic disorder?
The patients we see at DDC Clinic have rare genetic disorders. What exactly does that mean?
There are two components involved – rare and genetic disorder. Let’s look at them individually.
A rare genetic disorder is often defined as a disease or condition affecting fewer than 200,000 individuals in the United States.
There are over 6,500 orphan diseases affecting more than 25 million Americans.
Deoxyribonucleic acid (DNA) is the hereditary material of the human body. DNA is made up of four different chemical compounds, namely adenine (A), guanine (G), cytosine (C), and thymine (T). These four chemicals are linked together into a long string. Within each cell in the body, these strands of DNA exist in a very ordered fashion, namely as chromosomes.
Every cell of the human body is made up of 46 chromosomes which contain more than 30,000 genes. These genes give each of us our features or “traits,” for example, the color of our eyes and hair, how tall we are, the shape of our noses – and even our health.
These traits, controlled by the genes, are passed from one generation to the next in a fairly predictable way. They are “inherited.”
We said earlier that genes give us our health. Some medical conditions can be inherited, that is, passed from generation to generation. These inherited conditions are described as “genetic,” meaning there is a disorder in the makeup of the gene that is causing the medical condition.
Everyone has two copies of most genes, one from their mother and one from their father. Sometimes it only takes one damaged copy of a gene to cause disease while other times it takes two. Some disorders are more likely to occur in certain ethnic backgrounds or in families with a history of a disorder, and some may occur on their own or from a mix of factors. Most genetic disorders fall into one of three categories: dominant, recessive or sex-linked.