Familial hypercholesterolemia (FH) is a type of genetic condition that causes high levels of low-density lipoprotein (LDL), or “bad” cholesterol.
While some regard it as a rare disease, FH is actually quite common. It affects about
Still, FH is underdiagnosed. The American Heart Association (AHA) estimates that only
Doctors classify FH as either heterozygous (HeFH) or homozygous (HoFH). HeFH is less severe but much more common. This article will detail the HeFH subtype, including possible causes, symptoms, treatment, and more.
HeFH is an inherited disorder that involves a single DNA variant you get from one of your parents. The development of FH involves mutations in the LDL receptor, apolipoprotein B, or PCSK9 genes.
It’s also possible to have multiple related gene mutations. This is called compound HeFH.
FH affects your body’s ability to recycle LDL cholesterol, leading it to build up in your blood. With FH, it’s possible to have an LDL cholesterol level of
Heterozygous vs. homozygous familial hypercholesterolemia
HeFH refers to familial hypercholesterolemia that’s inherited from one parent only. Most cases of FH are the HeFH subtype.
On the other hand, you inherit HoFH from both parents. HoFH
Since HeFH is much more common, people often use FH and HeFH interchangeably when discussing symptoms, testing, and treatment. They’ll often differentiate the more serious HoFH.
HeFH doesn’t always cause symptoms. It can often go undetected unless you test for it.
However, some people with FH may develop cholesterol deposits around the body called xanthomas. These may be visible in the tendons of hands and elbows or around your eyes.
Developing these deposits before age 45 may be a sign of HeFH. Developing them in childhood could be a sign of HoFH.
People with HoFH may experience cardiovascular symptoms as early as childhood.
One downside to inherited diseases like HeFH is that you may not know you have it until problems develop. This is why it’s important to know your family health history, including cholesterol issues, and to discuss these with a doctor.
Additionally, a doctor will likely recommend the following tests:
- physical exam
- cholesterol screenings via blood testing
- scoring systems, such as the Simon Broome or the Dutch Lipid Clinic Network, which use a combination of family history, physical exam, and LDL cholesterol readings
- blood tests to rule out other health conditions that may affect your LDL levels, such as hypothyroidism or kidney disease
An LDL cholesterol reading in HeFH may be above 190 mg/dL. This is already considered a “very high level” and far above the optimal level of 100 mg/dL or less. In HoFH, typical LDL levels are even higher, reaching above 400 mg/dL.
As a rule of thumb, anyone with a known case of FH in their family should receive genetic testing for this condition. The
It’s also important to note that 20% to 30% of FH testing may be negative despite meeting other diagnostic criteria. This may be due to technical glitches or other issues with the test. It’s still possible to receive a positive result at a later time.
Did you know…
2015 research, one baby is born with familial hypercholesterolemia (HF) every minute.
While experts recommend diet and exercise for your overall health, these measures won’t help treat HeFH like they help manage high cholesterol that does not have a genetic component.
To reduce the risk of heart disease, a doctor may recommend starting cholesterol-lowering medications as young as
Having HeFH may also require more significant and timely LDL removal than medication alone can provide. This involves LDL apheresis, which is the direct removal of LDL from your blood before it accumulates. LDL apheresis is similar to dialysis in that you must repeat it every few weeks.
If genetic testing reveals a PCSK9 mutation, you may receive injectable PCSK9 inhibitors to help your liver remove LDL cholesterol more effectively.
HeFH is treatable with cholesterol-lowering medications. The earlier you receive a diagnosis and treatment, the better your outlook. The overall outlook for HeFH is more favorable compared with HoFH, the latter of which
Young people with untreated HeFH have a
While HeFH isn’t as serious as HoFH, it can still lead to serious health concerns, especially when left untreated. These may include:
HeFH is a type of familial hypercholesterolemia, an inherited disorder that causes abnormally high LDL cholesterol levels.
While not as serious as the HoFH subtype, HeFH still requires treatment to help prevent you from developing heart-related complications later in life.
If you have a family history of FH or a personal or family history of high LDL levels or early heart attack, it’s worth talking with a doctor about the possibility of HeFH. They can help you access the appropriate testing and treatments.