New diagnostic strategy aims to end diagnostic odyssey for rare diseases

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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