Familial hypercholesterolemia, or FH, is a disorder caused by a hereditary gene mutation. Since gene mutation causes FH, it’s hard to understand this common genetic disorder without first understanding genetic mutations. While not all mutations are bad, many can cause serious genetic disorders like FH.

What are Genetic Mutations?

Genes are made up of DNA sequences that code the proteins for life functions. Genetic mutations occur when these DNA sequences experience a permanent change. While mutations are a key element of evolution and cause diversity among organisms, not all mutations are benevolent. Changing the way that a protein is coded can make it unable to perform the life function it is intended to, which causes serious genetic disorders.

Gene Mutation Can Occur in Two Ways

Genetic mutations can either be inherited from a parent or occur during a person’s lifetime. Hereditary mutations that come from parents are present in every cell in the body for the person’s entire lifetime. Acquired mutations affect individual cells, and can happen either because of environmental factors or if there are errors when cells copy DNA during cell division. If acquired mutations occur in sperm or egg cells, they will appear in every cell of the child’s body just like hereditary mutations. Acquired mutations outside of sperm and egg cells cannot be passed down.

FH is Caused by an Inherited Genetic Mutation

Familial hypercholesterolemia is caused by an inherited genetic mutation on chromosome 19. This genetic disorder makes the body unable to effectively remove low density lipoproteins (LDL), otherwise known as bad cholesterol. While cholesterol serves important functions in the body, it is important that the level of LDL stays relatively low in the blood. High LDL leads to buildup in the arteries and blockages that can cause serious cardiovascular problems including heart attacks and strokes.  Approximately 1 in every 300-500 people has the FH mutation, but the vast majority do not know they have it and never get it adequately treated, leaving them unknowingly at an elevated risk for early onset heart problems.

The FH Mutation is Autosomal Dominant

Genetic traits can be either dominant, requiring only one parent to pass the trait down for the offspring to have it, or recessive, meaning that both parents must pass it down for the offspring to have it. The FH mutation is an autosomal dominant trait, so if one of your parents has FH, you have a 50% chance of having it as well. If both parents pass FH genetic mutations down, the offspring will have what is known as homozygous FH, which is far more serious than heterozygous FH inherited from one parent, and much more rare.  

To learn more about gene mutations, FH, and the treatments that are available to people who have the disorder, visit the Family Heart Foundation today. We are the only organization dedicated to raising awareness of this common but underdiagnosed genetic disorder in the United States.