If slim people have permanently high cholesterol levels despite a lot of exercise and a healthy diet, familial hypercholesterolemia (FH) may be present. FH is one of the most common genetic metabolic diseases. Usually the blood values are already conspicuous in childhood. Some patients in almost every family practice are affected by familial hypercholesterolemia (FH). Molecular genetic diagnostics is the gold standard for confirming the diagnosis. It provides the rationale for intensive treatment and simplifies the screening of family members. Early and unambiguous diagnostics can reduce the risk of arteriosclerosis to that of the general population for a large number of those affected.
- Tendinous xanthomas of the finger extensor tendons and the Achilles tendons
- Arcus corneae under 45 years of age
- early coronary heart disease or arteriosclerosis
- positive family history
Conspicuous laboratory values
- Cholesterol values ≥ 310 mg/dl for adults and ≥ 230 mg/dl for children/young people < 18 years
- LDL cholesterol value >190 mg/dl, in children under 16 years >155 mg/dl
- LDL cholesterol values > 325 mg/dl are almost proof of a FH according to the „Dutch Lipid Clinic criteria“.
Further information on diagnosis can be found in the recommendations of European Society of Cardiology.
Implementation of molecular genetic diagnostics
The following should be noted when requesting the examination:
- Sample material: 5 ml EDTA blood
- Request form "Molecular Genetic Diagnostics" (contains declaration of consent according to the Genetic Diagnostics Act), order: FH Genotyping
For the requirement "FH-Genotyping" we investigate with our gene panel "Hypercholesterolemia" those mutations which are responsible for up to 90% of cases. If no mutations are found and there is still a suspicion of FH, we will test the rare mutations after consultation with you.
Further Information on the FH
FH is one of the most common genetically caused (inherited) metabolic disorders. The prevalence is between 1:200 and 1:500, meaning that between 160,000 and 400,000 people are affected. These have a permanently increased cardiovascular risk.
The disease is underdiagnosed and undertreated. Probably only about 15% of cases are known in Germany. The diagnosis is typically made only after an early coronary outcome or in the case of a familial accumulation of myocardial infarctions.
Primarily mutations are present in the genes of the LDL receptor (80% of cases), the apolipoprotein B-100 and/or the PCSK9 protein, which consequently influence the function of the LDL receptor and lead to a disturbed LDL degradation.
Heterozygous affected patients make up the majority of patients (over 95%). In these patients, the risk of early coronary heart disease (CHD) is 20 times higher and symptomatic coronary artery disease before the age of 50 is likely. The homozygous form is extremely rare. If these patients are not treated, they often die of myocardial infarction before the age of 30.
The severity of the mutation has different effects on the cardiovascular risk in adulthood. Knowledge of the genetic defects present is therefore important for patient care.
The aim of the therapy is a significant reduction of the LDL level, whereby different target values apply depending on the stage of the disease. In therapy, statins are preferred and a healthy lifestyle is recommended. In particularly severe cases, lipoprotein apheresis is used. The newly available PCSK9 inhibitors are another treatment option for FH patients.