Familial combined hyperlipidemia — also known as mixed hyperlipidemia — is a genetic disorder that may pass from parents to children. It involves high fat or lipid levels in the body.

A person with this disorder has higher-than-average levels of lipids in their body. Lipids include cholesterol and fats called triglycerides, which store energy.

People with familial combined hyperlipidemia have a higher risk of developing plaque in their arteries. A plaque buildup can lead to cardiovascular events, including heart attack and stroke.

This article discusses mixed hyperlipidemia in more detail, including the causes, diagnosis, and treatment.

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Hyperlipidemia is the term for a range of disorders that cause elevated lipid levels.

Primary hyperlipidemia refers to the specific disorder that can pass from parents to children. Mixed hyperlipidemia is a type of primary hyperlipidemia.

Lipids are substances that do not dissolve in water but are soluble in organic solvents. Cholesterol and triglycerides are two of the types of lipids that people most commonly discuss with regards to cardiovascular health.

Elevated levels of these two lipids typically occur together and can contribute to the development of several cardiovascular health issues, including coronary artery disease, heart attack, and stroke.

An estimated 1 in 100 people have familial combined hyperlipidemia.

The exact cause of familial combined hyperlipidemia is unknown, as scientists have not yet identified the gene responsible.

However, they suspect that the condition occurs due to a combination of genetics and environmental factors. In other words, a person may need to have both the gene and an activating event or exposure to develop mixed hyperlipidemia.

Mixed hyperlipidemia is an inherited disorder. There is no guarantee that the condition will occur just because a person’s parents have the disorder. However, if one parent has mixed hyperlipidemia, a child has a 50% chance of developing the disorder themselves.

When both parents have the disorder, a child can get what some refer to as a “double dose.” When this occurs, they have a higher risk of developing coronary issues earlier in life.

Doctors may suspect mixed hyperlipidemia when blood tests reveal higher-than-normal levels of cholesterol. They will likely ask a person about their medical and family history. If their family history reveals the presence of the disorder in at least one parent, the person likely has mixed hyperlipidemia.

The most important test a doctor can order for diagnosis is a fasting lipid profile. This test looks at low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, and total cholesterol.

Prior to the blood draw, a person will need to avoid eating for 9–12 hours.

The American Heart Association (AHA) recommends that all adults over the age of 20 years undergo testing for blood cholesterol levels every 4–6 years. People with other risk factors may require more frequent testing.

Diagnosing mixed hyperlipidemia in children is complex due to a lack of long-term data that link lipid values in children to the occurrence of the disease in adults.

However, some research indicates that the diagnosis of hyperapolipoprotein B (hyperapo B) — an elevated level of a specific type of LDL — in children might be a good marker for diagnosing mixed hyperlipidemia in later life.

There is currently no cure for mixed hyperlipidemia. Instead, treatment is ongoing and focuses on helping prevent or reduce the risk of cardiovascular disease.

Several factors can affect the doctor’s choice of treatment approach. They include:

  • a person’s age at diagnosis
  • the presence of symptoms or other health conditions
  • the severity of the increased lipid levels

In some cases, a doctor may recommend lifestyle and habit changes as a first-line treatment. Lifestyle changes to manage cholesterol levels include:

  • quitting smoking
  • eating a diet focused on whole grains, fruits, vegetables, and lean proteins
  • maintaining a moderate weight
  • exercising regularly

If these changes are not effective enough, a doctor may prescribe medications to help lower lipid levels. The AHA notes that a doctor may prescribe various forms of medications, including:

  • statins, although these are not safe for people with liver concerns
  • ezetimibe (Zetia), which blocks the absorption of cholesterol
  • PCSK9 inhibitors
  • bile acid sequestrants
  • adenosine triphosphate-citrate lyase (ACL) inhibitors
  • fibrates
  • omega-3 fatty acid ethyl esters

The Social Security Administration (SSA) does not consider mixed hyperlipidemia a disability. However, it can potentially coexist with or lead to conditions that may qualify. These conditions include:

The AHA recommends that all adults over the age of 20 years get a lipid profile every 4–6 years. A person should make the doctor aware of any known risk factors for heart attack or stroke, such as family history, stress, physical inactivity, or smoking.

A person should talk with a doctor if they start to develop symptoms or issues that they cannot explain. The doctor can help determine what may be causing the issues.

A person should not ignore certain symptoms. Anyone who suspects that they are experiencing a heart attack or stroke should call 911 or seek emergency medical help.

The symptoms of a stroke can include:

  • slurred speech
  • numbness in the leg, arm, or face, usually on one side of the body
  • vision problems in one eye
  • confusion
  • a severe headache with no known cause
  • issues with movement or coordination

The symptoms of a heart attack can include:

A range of factors can affect the outlook for people with hyperlipidemia. These include:

  • the person’s age
  • how closely they stick to their treatment plan
  • how well their cholesterol levels respond to treatment

Treatment will likely have the highest chance of success if a person takes steps to ensure that they follow the plan as closely as possible. The person can also maximize their likelihood of a good outcome by:

  • eating a nutritious, well-balanced diet
  • engaging in regular exercise
  • reaching or maintaining a moderate weight
  • quitting smoking, if applicable

Making these changes can help a person reduce their risk of cardiovascular disease and live a longer, healthier life.

Mixed hyperlipidemia is a congenital disorder in which a person has naturally higher levels of cholesterol and fat in their body. Without proper treatment, it can increase a person’s risk of developing complications, such as cardiovascular disease.

The treatment often involves a combination of lifestyle changes, such as diet and exercise, to help lower cholesterol levels. In some cases, the use of medication may be necessary.