HYPOCHOL : A Genetically-based Strategy to Identify New Targets in Cholesterol Metabolism

Inclusion Criteria: * For index cases without family screening: o Patient with HBL: fasting LDL-C ≤ 50 mg/dl. * For familial affected cases: * Relative with HBL: fasting LDL-C ≤ 80 mg/dl and/or Apo B ≤ 50 mg/dl and at least one related family case suffering from HBL. All subjects, including familial non-affected cases, must give written consent (dated and signed) to participate at the constitution of biobank (including DNA samples and urine samples). Exclusion Criteria: * Use of lipid-lowering drugs (statins, fibrates, ezetimibe, bile-acid sequestering resin) or nutraceuticals known to affect lipids (red yeast rice, margarine and dairy with plant sterol) * Patient screened within an extreme metabolic disturbance (emergency situations, sepsis, hospitalization in intensive care unit) * Patients with hyperthyroidism, severe liver failure, end stage chronic kidney disease, serious pancreatic failure, anemia related to thalassemia or sickle cell disease, strict vegan diet or malnutrition * Refusal of the patient or his legal representative to participate in the study"