Familial hypercholesterolemia, usually shortened to FH, is an inherited condition that keeps LDL cholesterol high from the day a person is born, and it is thought to be the most common inherited condition affecting the heart and blood vessels [2].
This page provides general information. It does not replace advice from a doctor or another qualified healthcare professional.
Cholesterol is a waxy, fat-like substance the body needs, and low-density lipoprotein, or LDL, carries it in the blood [2].
Liver cells carry tiny structures called LDL receptors, which grab LDL cholesterol from the blood and pull it inside [6]. In FH an inherited gene change breaks that system: there are too few working receptors, or they cannot grip LDL, so cholesterol builds up and collects in artery walls as plaques that narrow the arteries [2,6]. Levels are raised from soon after birth, so exposure adds up for decades before anything is felt [3].
Names that get mixed up. FH is written familial hypercholesterolaemia in British English [2]. Most people with FH inherited one changed gene copy, called heterozygous FH, the form covered here; a changed copy from both parents causes homozygous FH, which is rarer, more severe and has its own guide [2]. FH also differs from high cholesterol driven mainly by diet and weight, and from a high lipoprotein(a) level.
FH affects an estimated 1 in 200 to 1 in 250 people in most countries [2]. A standard genetics reference gives roughly 1 in 250, noting that the older figure of 1 in 500 was probably too low [3]. United Kingdom guidance estimates 1 in 250 to 1 in 500, or roughly 130,000 to 260,000 people [4].
Those figures count people expected to have FH, not people diagnosed, and that gap is the most important thing here. A European expert panel reported that fewer than 1 percent of expected cases were diagnosed in most countries, and put the world total at 14 to 34 million people [19]. Diagnosis has improved since, though it remains patchy: the Family Heart Foundation now estimates that about 30 percent of people born with FH know they have it [18].
FH occurs in every ethnic group, and is more common in some communities, including Afrikaners in South Africa, Lebanese and Tunisian populations [2,3]. The true frequency is unknown in 90 percent of countries [3].
Genes are the instructions inside our cells, and a gene variant is a change in them [2].
The genes. LDLR carries the instructions for the LDL receptor itself and causes more than half of cases [2,3]. APOB affects the part of the LDL particle that locks onto the receptor, accounting for roughly 5 to 10 percent, and PCSK9 changes, which make receptors break down too quickly, are uncommon [3,6]. In about 40 percent of people who clearly have FH no cause is found with current testing, which does not make the diagnosis wrong [3].
How it is passed on. FH caused by LDLR, APOB or PCSK9 is inherited in an autosomal dominant pattern, meaning one changed copy is enough, so it usually passes from an affected parent to a child and each child has a one in two chance of inheriting it [2,6]. A rarer form, caused by LDLRAP1, is autosomal recessive: two changed copies are needed, and the parents usually have normal cholesterol themselves [2]. Diet, weight and smoking all affect cholesterol, though they are not why it is high in FH [2,3]. Doctors rule out other explanations first, including an underactive thyroid, poorly controlled diabetes and some medicines [4].
For most people there are none: high cholesterol does not hurt, so FH goes unrecognized for years while it quietly causes early heart disease [3].
Where cholesterol has been very high for years there can be visible signs, all easy to miss [7]:
Children with heterozygous FH usually have none of these [3,4].
When to seek urgent help. FH itself is not an emergency. A heart attack or a stroke is. Call emergency services immediately for chest pain that feels tight or like squeezing, pain spreading to the arms, neck or jaw, or severe difficulty breathing [24]. Call immediately too for sudden face drooping, weakness in one arm, or slurred speech, even if the symptoms stop [25].
Diagnosis usually starts with a family doctor, who asks about illness in the family, arranges a blood test called a lipid profile, and checks for the signs above [7].
The two sets of criteria. The Simon Broome criteria call FH definite when cholesterol is above set levels, 7.5 mmol/L total or 4.9 mmol/L LDL in an adult and 6.7 mmol/L total or 4.0 mmol/L LDL in a child under 16, plus either tendon xanthomas in the person or a close relative, or a gene change on DNA testing; the same levels plus a family history of an early heart attack or of very high cholesterol make FH possible [5,8]. The Dutch Lipid Clinic Network criteria score family history, personal history, signs and LDL cholesterol as points: above 8 means definite FH, 6 to 8 probable, 3 to 5 possible [8]. Either leads to referral to a lipid clinic [4,7].
Genetic testing. A blood sample can be checked for a change in one of the FH genes. A change is found in about three out of four people with FH, and where none is found the diagnosis still stands [3,4,9].
Cascade testing, the highest-value step. Once FH is confirmed in one person, their relatives can be offered testing. United Kingdom guidance recommends DNA testing of first-degree relatives, meaning parents, brothers and sisters and children, then second-degree and where possible third-degree relatives [4]. A European panel found cascade screening the most cost-effective way to identify new cases, with around half of relatives tested inheriting the change [19]. As the Family Heart Foundation puts it, you never find a person with FH, you find a family [18].
Children. Where one parent has confirmed FH, guidance recommends offering the child a DNA test before age 10, or a cholesterol test if no gene change is known [3,4,10].
There is no cure. Treatment is lifelong, and statin-based treatment significantly increases survival in people with FH [3,4].
Statins first. A high-intensity statin is the usual starting treatment, aiming to cut LDL cholesterol by at least half, with the dose raised as high as a person can tolerate [4,12].
Adding to a statin. The 2026 United States guideline lists ezetimibe, bempedoic acid and PCSK9 inhibitors as the options to add when a statin is not enough [1]. Ezetimibe and bempedoic acid are daily tablets [13,16], PCSK9 inhibitors are injected every two to four weeks [14], and inclisiran targets the same protein every three to six months [15]. Lipoprotein apheresis, which filters cholesterol out of the blood through a machine, is used mainly for the homozygous form [4,17]. Availability differs by country: in the United Kingdom PCSK9 inhibitors are hospital-prescribed against set cholesterol thresholds [14], and inclisiran is funded for FH in Scotland and Wales but not in England unless cardiovascular disease is established [15].
Children, calmly and factually. Treatment for a child with FH usually does begin in childhood, which often surprises parents. United Kingdom guidance recommends offering statins by the age of 10, or at the earliest opportunity after that, and a statin may be started as early as age 8 [3,4]. Treatment is decided with a specialist who works with children, taking account of the child’s age, the cholesterol level and the family history [4]. The reasoning is arithmetic: cholesterol has been high since birth, so starting earlier means less lifetime exposure.
Pregnancy. Cholesterol-lowering medicines are generally paused around pregnancy: United Kingdom guidance advises stopping three months before trying to conceive [4], and the 2026 United States guideline advises deferring most during conception, pregnancy and breastfeeding [1].
Most of daily life is unaffected. The pattern is long-term: medicine every day, blood tests, and review with a specialist who knows the condition [4]. Keep a note of which medicines have been tried and which relatives have been offered testing, since guidance treats cascade testing through a family as part of routine review [4]. Lower saturated fat, regular activity, avoiding tobacco and a healthy weight sit alongside medicine rather than instead of it [1,3].
HEART UK makes two points to families worth repeating: there is no reason to feel guilty about passing on a gene, since nobody chooses their DNA, and a child diagnosed and treated early can expect to live a normal, healthy life [10]. Changing habits as a whole family works better than singling one child out [4,10].
Clinical trials are research studies that test whether a treatment or approach works and is safe. Cholesterol lowering is an active research area, so studies in FH come up reasonably often, including some for teenagers. Deciding whether to look into one is a personal choice, and it helps to take it in steps.
It is worth being clear on:
Every trial has rules about who can take part, called eligibility criteria. For a study in FH, they might include a confirmed genetic diagnosis, an LDL cholesterol level above a set number, a stable dose of statin and ezetimibe beforehand, whether a person already receives a PCSK9 inhibitor or inclisiran, and an age range limited to adults or to a childhood age band.
trialport’s medifit helps people consider information related to possible medical suitability. It does not diagnose a condition, confirm eligibility or replace formal screening by the study team.
Explore familial hypercholesterolemia clinical trials through trialport
A study can look like a good match on paper and still be hard in practice. Worth thinking through:
trialport’s readifit helps people reflect on their understanding, motivation, time, routines, support, emotions and practical arrangements.
Useful questions to put to a research team:
Taking part is voluntary. A person can ask questions, speak with people they trust and choose not to participate.
Search for clinical trials at app.trialport.com.
Study status checked: 3 August 2026. Research moves, and what is being studied changes, so this describes broad areas rather than a fixed list.
Where you want current trial information, search at app.trialport.com.
In the United Kingdom, HEART UK is the cholesterol charity, with pages on genetic testing, being a parent with FH and medicines including statins, ezetimibe and inclisiran [6,9,10,12,13,15]. The NICE guideline sets out what should be offered [4].
In the United States, the Family Heart Foundation is the clearest source on family screening [18], MedlinePlus Genetics is reliable on the genetics [2], and GeneReviews carries the clinical detail [3]. Across Europe, the European Atherosclerosis Society publishes the guidance clinicians follow [20].
Coverage elsewhere is thinner, and dedicated FH organizations are uncommon in Australia, New Zealand, much of Asia, the Middle East, Africa and South America [3]. Where no local group exists, a hospital lipid clinic or national heart charity is the best first contact.
If I have FH, does that mean my children will?
Each child has a one in two chance of inheriting it [6,18]. Guidance recommends offering the child a DNA test before the age of 10 [4,10].
Can I treat FH with diet and exercise instead of medicine?
No. Both help and are recommended alongside treatment, though cholesterol in FH cannot usually be brought down far enough by lifestyle change alone [3,18].
Why would a child need statins?
Cholesterol is high from birth, so damage accumulates for years before anyone notices, and treating earlier reduces lifetime exposure. United Kingdom guidance recommends offering statins by age 10, started by a children’s specialist [3,4].
I have no lumps or rings around my eyes. Can I still have FH?
Yes. Most people with FH have no visible signs, and their absence does not exclude the diagnosis [4,7].
Will treatment let me live a normal life?
Statin-based treatment significantly increases survival in people with FH [3], and HEART UK tells parents that a child diagnosed and treated early can live a normal, healthy life [10].
Written by: trialport editorial team
Reviewed by: Keith Berelowitz, Founder and CEO, trialport
Reviewed on: 3 August 2026
Next review due: 3 August 2027
References last checked: 3 August 2026