Pelizaeus-Merzbacher disease (PM) is an X-linked leukodystrophy causing developmental delay, nystagmus, hypotonia, spasticity and variable intellectual deficit. Three forms are described according to age of onset and severity: neonatal forms (+ severe), classical form (moderate, first 2 months of life) and transient form (the least serious 2-3 years). Prevalence is estimated at 1/400,000. We report the sighting of a 12-year-old and 8-month-old girl, with no significant history, from a non-indigenous marriage. Presents since the age of 5 months a bilateral horizontal nystagmus, myoclonia and a psychomotor retardation and whose examination revealed a pyramidal syndrome and a discreet hepatomegaly. The biological balance objectivéhyperlactatemie, hyperammoniémieet Chromatography of Amino Acids in urine showed an increase in glycine, alanine and tyrosine with Amino Acid chromatography in the blood and chromatography of Organic Acids normal. MRI brain objectified a demyelinating aspect of the white substance and atrophy of the corpus callosum. PEV pathological retina-cortical conduction, PEA altered left, Muscle biopsy absence of shredded red fibers and genetic study confirms PelizaeusMerzbacher disease like.