The principal aim of the study is to avoid the diagnostic wanderings of patients suffering from a peroxisomal disorder. For this purpose, a new diagnostic strategy is proposed. It rests on functional metabolic explorations and gene studies directly connected to a first-line enlarged physico-chemical detection of metabolites from peroxisomal origin in clinically suspect patients.

Inclusion Criteria:

I - CLINICAL/BIOLOGICAL CRITERIA For an efficient screening of the patients of the 4 contributing University Hospitals (Amiens, Caen, Lille and Rouen), various inclusion criteria were selected: In general, the inclusion criterion is the existence of a positive biology or in turn the persistence of a clinical suspicion in spite of a negative biology.

I A - Children from 0 to 17 years:

The clinical inclusion criterion is a positive biology or the persistence of a clinical suspicion in spite of a negative biology. This persistent clinical suspicion is left to the discretion of the clinician. It is essentially based on the existence of a family history of peroxisomal (or suspected) pathology and / or the combination of several clinical signs of craniofacial dysmorphism, skeletal abnormalities, encephalopathy (seizures, ataxia, Hypotonia), demyelinating peripheral neuropathy, ophthalmopathy (retinopathy, cataract), hepatic impairment (hyperbilirubinemia, hepatomegaly, cholestasis) and growth retardation OR I B - Adults from 18 years

The neurological symptoms of peroxisomal diseases in adulthood are numerous and non-specific. The three inclusion criteria selected for patient selection are as follows:

• Cognitive impairment (delayed acquisition or regression) and / or leukodystrophy AND At least one of the following signs: Cerebellar ataxia, Spastic paraparesis, Peripheral neuropathy, Neurosensory deafness, Retinitis pigmentosa, Epilepsy, Unexplained unexplained vigilance, Peripheral corticotropic insufficiency +/- gonadotropic AND
• no evidence for an extraperoxisomal origin of the patient disease stated after the usual paraclinic explorations

II - NON CLINICAL CRITERIA

• Social insurances
• Having understood the information note and having signed the informed consent form.
• Patients under guardianship or curatorship may be included, since peroxisomal diseases as a cause of neurological impairment may potentially lead to guardianship.

Exclusion Criteria:

• Pregnant or nursing women
• Person deprived of liberty or in emergency situations

The studied population is represented by only one group of patients checking the inclusion criteria and recruited in the 4 University Hospital centers (Amiens, Caen, Lille and Rouen). For each patient, diagnostic exploration will start in patients with the common inclusion criteria and will include the study of all biochemical parameters susceptible to be disturbed In peroxisomal pathologies (Biology component). Based on the data obtained, the inclusion of patients will lead to biological confirmation tests (Cell Exploration and Enzymology) and molecular studies (Molecular Biology).