Pelizaeus-Merzbacher Disease: A Rare Cause of Nystagmus and Developmental Delay

Abstract

Pelizaeus-Merzbacher disease (PMD) is an X-linked leukodystrophy of the central nervous system characterized by a developmental arrest in myelin formation. It is classified into five phenotypes, with different severity. The most common clinical features are nystagmus, spasticity, tremor, ataxia, and hypotonia. A 11-month-old child was referred to the Neuropediatric Unit due to nystagmus, hypotonia, and developmental delay. Brain magnetic resonance imaging showed signs of diffuse hypomyelination (absence of the T2 low signal in the supratentorial white matter). Molecular analysis revealed a duplication in the PLP1 gene, confirming the diagnosis of PMD. PMD should be considered in infants with nystagmus, hypotonia, and cognitive impairment. Neuroimaging supports the diagnosis, and it should be confirmed by genetic testing. Since no definitive treatment is available, management of this disorder is mainly symptomatic and a multidisciplinary approach for these patients is essential for an improvement in their quality of life.