Study of the Absorption of Vitamin E Water-soluble Form (Pegylated) in the Familial Hypocholesterolemia With Chylomicron Retention

Inclusion Criteria: * Patient suffering from familial hypocholesterolemia by retention of chylomicrons * Systematically followed in the department of Gastroenterology and Paediatric Nutrition in Women Mother Child's Hospital or in the endocrinology department of GHE (Louis Pradel Hospital); * During treatment with oral vitamin E; * over the age of 3 years and weighing over 16 kg at the time of inclusion * For which there is a signed informed consent from the patient or parents / guardians in the case of a minor patient, and benefit from social security coverage. Exclusion Criteria: * Patient with encephalopathy * Hypersensitivity to the active substance or the excipients of Vedrop * A suspected allergy to local anaesthetics (including xylocaine) * Patients who may not be compliant to treatment (psychiatric); * In case of refusal to participate in the study from the patient and / or parents or legal guardian; * Patients unable to consent (if patients with encephalopathy)