Pelizaeus-Merzbacher-like disease (PMLD) is an autosomal recessive hypomyelinating leukoencephalopathy disorder with a genetically heterogeneous pattern. It is virtually identical to Pelizaeus-Merzbacher disease (PMD) but without a mutation in the PLP1 gene that causes PMD. The prevalence is unknown, affecting males and females with equal frequency. PMLD is characterized by early-onset nystagmus, impaired motor development, ataxia, choreoathetotic movements, dysarthria, and progressive spasticity.
There is no standard treatment for individuals with Pelizaeus-Merzbacher like disease. Treatment is based upon specific symptoms present and supportive care.
Bugiani et al. (2006) described the clinical and neuroimaging features of 13 patients with Pelizaeus-Merzbacher-Like Disease (PMLD) from 10 families. Eight of these patients (patients 5 to 12) were from a multi-consanguineous Saudi family. All patients presented in the neonatal period with rotatory or pendular nystagmus. Around the age of 6-months they had moderate to severe psychomotor delay, followed by cerebellar ataxia, intention tremor, and slurred, dysarthric speech, evolving into spastic tetraparesis. Patients 9 to 12 had more severe symptoms; they were unable to walk, and their cerebellar tremor was severely disabling. All patients were alive, ranging from age 4 to 23-years. Ophthalmologic examination showed pale optic disc, and frank optic atrophy in patients 5 and 6. All patients had normal motor and sensory nerve conduction velocities. MRI revealed a remarkable, diffuse myelin deficiency in all patients, except in patient 5, who displayed a much lesser degree of signal changes. A 22-bp duplication mutation in the GJC2 gene was found in the eight PMLD patients.