Histopathologic and biochemical analysis of classic Pelizaeus-Merzbacher disease.

An autopsy study of an 11-year-old boy with the classic type of Pelizaeus-Merzbacher disease is presented. He developed normally until 5 years of age when he began to deteriorate with scanning speech and gait abnormality. Auditory brainstem responses were normally preserved. At the age of 11 years, 8 months, he died of pneumonia while in a vegetative state. The neuropathologic findings suggested a typical classic type of Pelizaeus-Merzbacher disease and biochemical analysis of cerebral white matter demonstrated a decreased ratio of long-chain fatty acids (greater than or equal to C19) to short- and medium-chain fatty acids (less than C19). These findings suggested defective myelin synthesis as the etiology of Pelizaeus-Merzbacher disease; comprehensive classifications of the disease are expected to include both pathologic and biochemical parameters.