What is a Gene?
Every part of your body, from your eye color to your immune system, is determined by DNA (deoxyribonucleic acid). Your DNA molecules carry the instructions for your biological makeup, which your cells follow to build proteins that help your body grow and work.
The individual sections of your DNA that provide specific instructions for each of your physical traits and functions are called genes. The complete set of genes that make up your DNA is known as your genome. Different versions of individual genes within a genome are what cause different traits between people.
How do you get your genes?
Your specific DNA is determined by your biological parents. Your genome has two versions of every gene, one that you inherit from your father and one that you inherit from your mother. The combination of genes you inherit from your parents determines every aspect of your biological makeup, including what you look like, how your body works, and what diseases you may have.
How do genes work?
Your chromosomes are long strands of DNA that contain your inherited genes. You typically inherit one set of 23 chromosomes from your mother and one set from your father. For most genes, each set of chromosomes contains one copy of each gene from that parent, giving you two copies of each gene.
The interaction between these two versions of a gene in your chromosomes is what determines your specific inherited traits. The different potential interactions between gene versions are called inheritance patterns.
Most gene variants can be classified as dominant, where you only need one copy of the gene version to show the trait, or recessive, where you need two copies of the same gene version (one from each parent) for a trait to show. In some cases, inheritance patterns may lead to codominance (when you show the traits from each gene version you inherit at once) or incomplete dominance (when the two gene versions you inherit blend to form a new trait).
Your specific inheritance patterns determine your physical characteristics, body function, and health conditions.
Can your genes change?
Your cells regularly divide and multiply to grow, repair, and maintain your body. During this process, the new cells copy your DNA to replicate the specific instructions for your body determined by your genes.
Sometimes cells make a mistake when copying DNA, much like a typo. These changes, known as genetic mutations, can impact many aspects of your body and how it functions, including your immune system.
Do genes cause Primary Immunodeficiency?
Primary Immunodeficiency, also known as Inborn Errors of Immunity, occurs when a person is born with a genetic mutation that affects the function of the immune system.
Many of the genetic defects that cause Primary Immunodeficiency are passed down through the genetic inheritance process outlined above. In some cases, Primary Immunodeficiency is caused by a mutation that is brand new in a person’s genes, rather than passed down from a parent. This is called a de novo genetic mutation and forms during a stage of the reproductive cycle.
Today there are over 550 identified genetic defects that cause Primary Immunodeficiency. Learn more about Primary Immunodeficiency here.
