Heart & Stroke Conditions Explained


Familial hypercholesterolemia (FH)

Familial hypercholesterolemia (FH) means there is an exceptionally high cholesterol level in the blood from birth unrelated to diet and lifestyle.

It is a common inherited disorder which can cause premature coronary heart disease (heart disease in early life) due to the remarkably high cholesterol level, in particular the LDL cholesterol (LDL-C).

At least one in every 250 – 500 people has FH but over 90% of people with FH have not been properly diagnosed. With a population of almost 5 million people in Ireland, this means that approximately 10,000 people at least, have FH.

There are two main types of FH:

Heterozygous FH (HeFH) is the most common and happens when you inherit the condition from one parent. There is a 50:50 chance a child can inherit an altered gene from the affected parent.

Homozygous FH (HoFH) is very rare and only happens if both parents have the condition and a child inherits an altered gene from both parents.

Although it is inherited, a lot can be done to treat the condition, especially when it is discovered early. Because of this, FH should be detected and treated as early as possible.


Familial hypercholesterolemia (FH)

This condition is present from birth and the majority of people have no symptoms. Families need to be aware to have their cholesterol checked and in particular LDL-C if there is a strong family history of premature Heart Disease.

Unlike many people who develop heart disease or have a stroke in middle and old age, the very high cholesterol level in FH leads to heart disease and heart attack in early life. This very high cholesterol level may be the only sign of FH.

Sometimes signs of FH can be seen in your skin and tendons, these include:

  • Pale yellow lumps near your knees, ankles, knuckles, elbows, and back of your hands. These are called xanthomas.
  • Yellow marks around your eyes are called xanthelasmas.
  • A pale or white ring around the outside of your iris, the coloured part of your eye, may be a sign of a high cholesterol level and FH.


Familial hypercholesterolemia (FH)

A high blood cholesterol level is one of the many factors that increase your chance of getting heart disease or having a stroke. For most people, your blood cholesterol level depends on what you eat and drink and, to a lesser extent, on the genes inherited from your parents. With FH, the cholesterol level – most specifically the LDL-C, is exceptionally high and is mainly caused by inherited genes.

We inherit many characteristics from our parents by the information carried on DNA where our genetic code is arranged on 23 pairs of chromosomes. In people with FH, one of three genes involved in the removal of LDL-C from the blood may be altered.

Cholesterol is made in the body mainly by the liver. Normally, the fat and cholesterol you eat is brought into the bloodstream from your stomach to your liver. Your liver produces small particles called lipoproteins. Low-density lipoproteins (LDL) carry the cholesterol to all the cells in your body where it is needed to build cells, make some hormones and to produce bile acids that are needed for digestion.

When the LDL-C reaches a cell the LDL plugs itself into a socket on that cell called a receptor. The cell then absorbs the cholesterol and uses it.

In people with FH, the faulty gene results in half of these receptors being either missing or not functioning normally. This means that cholesterol levels in your blood remain too high (often between 7.5 and 15 mmol/l) because there are not enough receptors to absorb all the cholesterol. Very rarely (one in a million), there are no LDL receptors on the cells. In these rare cases, cholesterol levels are so high (between 20 and 30 mmol/l) that heart disease develops in infancy.


Familial hypercholesterolemia (FH)

Without treatment, up to eight in every ten men with FH will have a heart attack. Half of these people will die before 60 years of age. Women with FH also develop early heart disease but usually some years later than men. Some people with FH may be disabled or may die from heart disease very early in life, often as early as 20 years of age. Because of this, FH should be detected and treated as early as possible.


Familial hypercholesterolemia (FH)

In most cases, FH is diagnosed by a blood test to check the cholesterol level, and reviewing your clinical and family history. However, people are often only diagnosed with FH after they have experienced an event such as a heart attack or stroke.

FH is passed from parent to child. If one parent has FH, half of their children are also likely to have FH. This means that if you have FH, it is important that all the members of your family have a cholesterol test to find out who else might be affected. Children born to a parent with FH can be tested from the age of 2 years and it is recommended they are tested by the age of 10 years.

Your doctor will use a risk factor scoring system if FH is suspected. Your gender, age, family history, cholesterol level, your own clinical history and physical examination will help to guide the screening to establish a definite FH or possible FH diagnosis.


Familial hypercholesterolemia (FH)

If you have FH, healthy eating alone will not lower your blood cholesterol enough, as your liver cannot remove excess cholesterol from your blood the same as someone who doesn’t have FH. You will need a combination of medicines to lower your cholesterol and support and guidance with improving lifestyle and diet. For most people with FH, the aim of treatment is to lower the LDL-C level by at least half.

Lowering a high cholesterol level reduces the risk of stroke, heart attack, angina and the need for heart surgery. A healthy lifestyle is important for everybody. It is even more important for people with FH. This includes reducing fat intake, especially saturated or animal fat, and eating a variety of foods, using the Food Pyramid as your guide. Usually, a change in eating habits to more heart-healthy options can reduce a person’s cholesterol level by about one fifth.

Statins are the most commonly prescribed type of cholesterol lowering medicine. They slow down the production of cholesterol in your liver and are very effective at lowering LDL-C and thereby preventing heart disease. There are several other different types of medicines which can be used to lower blood cholesterol levels either instead of, or as well as, statins. Other medicines work by helping to prevent your intestines from absorbing cholesterol either from your food or from bile acids. A new class of drugs which inactivates a protein in the liver are now available, allowing more LDL-C to be absorbed by the liver from the body.

Before taking any new tablets, make a list of all medicines you are already taking and tell your doctor. You may need to change the dose or the time of day you take some tablets so that your current medicines and the newly prescribed cholesterol-lowering drug all work well together. Make sure you tell your healthcare provider if you have any side effect that bothers you or that does not go away

Support for You

Familial hypercholesterolemia (FH)

The Irish Heart Foundation offers a range of free support services to those affected by heart disease or stroke that can greatly improve their quality of life. These include support groups, physical exercise classes, therapy sessions and more.

For more information on these supports, see our Patient Supports page.

If you have any questions about heart disease or stroke, you can also call the Irish Heart Foundation’s Nurse Support on (01) 668 5001 to speak to a nurse specialist who will answer your questions, and give you guidance and reassurance.


Familial hypercholesterolemia (FH)

Step by Step through Heart Attack – our patient information booklet

Angina – our guide from symptoms to treatment

Step by Step through Heart Medicines – our patient information booklet

Your Heart Health – view our articles on ways to manage and reduce your risk factors, from being active to stresscholesterol, losing weightblood pressure and more.

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