Method: All patients were evaluated in neurogenetics clinics. A full medical history was taken and the following were performed: neuroimaging studies (CT, MRI with spectroscopy), ophthalmologic and auditory evaluations, neurophysiologic studies (EEG, ERG, EMG/ NCV), hormone and biochemical tests, muscle biopsy with OXPHOS analysis, screening for IEMs (lysosomal studies; peroxisomal/sterol panels; cholestanol dosage; organic acids, sulfatides and aminoacid chromatography; analysis of GAG) and, when indicated, nerve/skin biopsy for EM studies, karyotype and molecular tests. Results: In forty patients it was possible to establish a diagnosis for the leukodystrophy. X-ALD, metachromatic leukodystrophy and Krabbe disease were the commonest inborn errors of metabolism implicated in the pathophysiological of the “metabolic leukodystrophies”. Infantile Refsum disease, Canavan disease, AMACR deficiency, Niemann-Pick type C were other rare IEMs diagnosed. It was worthy of note the fact that Vanishing White Matter disease was a leading cause of leukodystrophies in our patients (eight patients). Conclusion: Almost 50% of patients with white matter abnormalities remain without a specific diagnosis even after an exhaustive investigation. Therefore a specific protocol for investigation is crucial. Treatment options are becoming a reality for some disorders, so reaching a specific diagnosis is important so that patients can be offered appropriate therapeutics.