Pelizaeus-Merzbacher Disease, Easily Misdiagnosed as Cerebral Palsy: A Report of a Three-generation Family

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder affecting myelination of the central nervous system, and is caused by mutations of the proteolipid protein 1 (PLP1) gene. Clinical manifestations of PMD are variable and major features include progressive nystagmus, spasticity, tremor, ataxia, and psychomotor delay. We describe a classical PMD patient who had been misdiagnosed as cerebral palsy. He had nystagmus and psychomotor delay since infancy and tremor with ataxia developing gradually. Brain MRI revealed demyelination over white matter of the cerebral hemispheres and posterior limbs of the internal capsules. Positive family history led to subsequent mutation analysis, which identified a novel mutation (c.88G>C) in PLP1 in the proband, as well as his affected brother and maternal uncle, and asymptomatic maternal grandmother, mother and two sisters. Therefore, PMD should be considered in a cerebral palsy-like patient with or without positive family history. Mutation analysis is crucial for early diagnosis and further genetic counseling.