Familial hypercholesterolaemia is a very common hereditary and silent disease. It is asymptomatic, so most people don’t know they have it until something happens and the diagnosis is made known. According to the Family Hypercholesterolemia Foundation, this disease affects 100,000 people in Spain alone.
Development of familial hypercholesterolemia
Unfortunately, the mutation that causes familial hypercholesterolemia is dominant. Depending on the characteristics of the parents, the inheritance of this disease can be:
- Heterozygous: the gene is inherited from a parent; the other inherited gene is healthy.
- homozygous: the gene is inherited from both parents.
Many mutated genes have been discovered which, once inherited, They can lead to the development of familial hypercholesterolemia. The most common is the low-density lipoprotein receptor gene (rLDL gene).
LDL is often incorrectly referred to as “bad cholesterol”. This is because they bind to cholesterol and circulate it through the arteries.
The LDL receptor is responsible for removing this lipoprotein (along with cholesterol) from the bloodstream and introducing it into cells for use.
In this pathology, this receptor is damaged, therefore LDL, along with cholesterol, builds up in the arteries.
Diagnosis of familial hypercholesterolemia
The first stage in the diagnosis of familial hypercholesterolemia is, as almost always, the clinical suspicion.
Your primary care physician will look at many of the following parameters in your patient.
- Total cholesterol >300mg/dL.
- Normal triglycerides <200mg/dL. Triglycerides are a different type of fat than cholesterol. This is why they are generally not affected by this pathology.
- Hypercholesterolemia in relatives first degree (parents, siblings, children).
- Heart attack or other atherosclerotic disease at an early age. It is considered “first age” before age 55 in men and before age 60 in women.
- other signs, AS xanthomas tendon (accumulation of cholesterol that forms “lumps”, in this case in the tendons) or corneal arc (cholesterol accumulates in the cornea forming a circumference in its peripheral area).
Criteria of the Netherlands Lipid Clinics Network
After establishing the clinical suspicion, the parameters indicated below are analysed.
Points are awarded based on the characteristics that the individual presents. At the end of the examination of all the parameters, all the points obtained are added up.
- Referring to Family history:
- 1 point:
- First-degree relative with early coronary and/or vascular disease.
- First-degree relative with LDL cholesterol ≥ 210 mg/dL.
- 2 points:
- First-degree relative with xanthomas and/or corneal arch.
- Under 18 years of age with LDL cholesterol ≥ 150 mg/dL.
- 1 point:
- As for the Physical exam:
- 4 points: corneal arc before the age of 45.
- 6 points: tendon xanthomas.
- In the fasting analysis (provided triglycerides are below 200 mg/dL):
- 1 point: LDL cholesterol between 155 and 189 mg/dL.
- 3 points: LDL cholesterol between 190 and 249 mg/dL.
- 5 points: LDL cholesterol between 250 and 329 mg/dL.
- 8 points: LDL cholesterol ≥ 330 mg/dL.
- Genetic determination:
- 8 points: functional alteration of the LDL receptor gene.
If the sum of the points gives a result equal to or greater than 8, the diagnosis of familial hypercholesterolemia is certain. If the sum of the points is 6 or 7, the diagnosis is considered only probable.
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