If you could zoom in on the human body, past the skin, muscles, essential organs and bones and marrow, you would find cells – billions of them. And what’s inside these cells, too small to be seen with the human eye, is essential. Chromosomes, DNA (deoxyribonucleic acid) and genes are elaborate instructions that determine everything about a human body. They give cells direction on how to form and function in the body.
In short, cells contain chromosomes; chromosomes contain DNA; and DNA contains gene segments.
According to the National Human Genome Research Institute, genetic disorders are diseases and conditions caused by:
- a change in the DNA sequence away from the normal sequence
- a mutation in one gene
- mutations in multiple genes
- a combination of gene mutations and environmental factors
- damage to chromosomes (changes in the number or structure of entire chromosomes, the structures that carry genes)
What are Chromosomes?
Chromosomes are threadlike structures and they exist to carry genomic information from cell to cell. They are made of protein and a single molecule of DNA. http://Females have two X chromosomes in their cells, and males have one X chromosome and one Y chromosome.
Cells typically contain 46 chromosomes, 23 pairs of which are from a person’s father, and the remaining 23 pairs are from their mother. A child born with Down syndrome has an extra copy of chromosome 21.
What is DNA?
DNA is the molecule that carries genetic information for the development of the functioning of an organism, according to the National Human Genome Research Institute. Like cells, DNA is too small to see without a powerful microscope.
It is made of two linked strands that, when twisted together, create a shape known as a double helix. The strands of DNA have a backbone that consists of phosphate groups and alternating sugars called deoxyribose. Four bases are attached to each sugar. These bases are adenine (A), cytosine (C), guanine (G), or thymine (T). The sequencing of the bases is what encodes biological information, such as the instructions for making RNA molecules or proteins.
What are Genes?
Genes are the basic unit of inheritance and are passed from parents to offspring, according to the National Human Genome Research Institute. These essential building blocks of information provide the information needed to specify different traits. Genes encode the information for making proteins, “the bricks and mortar that make up our cells and tissues,” necessary for an array of essential functions.
Mutated genes and damage to chromosomes can cause genetic disorders, which are passed from parent to child. According to the National Human Genome Research Institute, genetic conditions include Alpha 1 Antitrypsin Deficiency, Sickle Cell Disease and many others.
According to the U.S. National Institutes of Health, almost 80 percent of rare diseases are caused by a variant in a single gene, which opens the possibility of gene therapy as a potential treatment. A patient’s decision to be treated with gene therapy is a complex one. Learn about shared decision-making.
