Partial seizures in leukoencephalopathy with swelling and a discrepantly mild clinical course

Megalencephalic leukoencephalopathy with subcortical cysts in two siblings owing to two novel mutations: case reports and review of the literature

Megalencephalic leukoencephalopathy with subcortical cysts is a rare leukodystrophy characterized by macrocephaly and a slowly progressive clinical course marked by spasticity and cognitive decline. We report two full siblings with neuroimaging studies and clinical courses typical for megalencephalic leukoencephalopathy with subcortical cysts, in whom a pair of novel mutations in the MLC1 gene was identified. We review the current knowledge of this disorder in relation to the patients reported.

Epilepsy in vacuolating megalencephalic leukoencephalopathy with subcortical cysts

Vacuolating megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a disorder characterised by acquired macrocephaly, developmental motor delay of varying degrees, slowly progressive cerebellar and pyramidal signs, and initially preserved intellectual function. More than 60% of the published cases had epileptic seizures. In this study, we analysed the seizures and EEG findings of nine patients with MLC. Six patients (66.6%) with moderate to severe neurological impairment had epilepsy, four with partial and two with generalised seizures. The EEG of five epileptic patients revealed epileptogenic foci over the temporal, frontal and parietal regions with variable predominance during waking and sleep. The facilitation of spike-and-wave paroxysms by eye closure, by intermittent photic stimulation and by hyperventilation were determined in four patients. Four patients also showed abnormalities in the background activity. In conclusion, we think that epilepsy is a significant component of MLC compared to the other leukodystrophies. The elucidation of the underlying molecular defect may explain the unusual pathogenetic relation between this leukoencephalopathy and the associated seizures.

Proton MR spectroscopy demonstration of taurine peaks in megalencephalic leukoencephalopathy with cysts

Taurine is an amino acid. It has roles in neurotransmitter activities, facilitates synaptic connections, and possesses cyto-protective properties. Normally, it is invisible on proton MR spectroscopy acquired at low field strengths (i.e. 1.5T). In a patient with megalencephalic leukoencephalopathy with cysts (MLC), distinct taurine peaks centered at 3.35ppm were found on hybrid-CSI spectroscopy obtained at 1.5T with a long TE value (i.e. TE=135ms). This suggested increased concentrations of this metabolite in MLC. In this leukoencephalopathy taurine may be linked to a metabolic disturbance related with neurotransmitters associated with a disturbance in synaptic connections, and cyto-protective mechanisms. Further spectroscopic and clinical studies are required to evaluate this observation.

Leukoencephalopathy with patchy lesions, temporal cystic degeneration, and normal head size

A 5 yr old girl is reported with patchy white matter lesions, cystic degeneration of the temporal tips, normal cortex, and normal cerebellum, documented by FLAIR, and diffusion-weighted MRI. This condition differed from the entity megalencephalic leukoencephalopathy with cysts by lack of diffuse involvement of the white matter and cortical thinning, by presence of a normal head size, and existence of a non-progressive, severe clinical condition. Occurrence of cystic degeneration in the temporal tips distinguished the condition from other leukoencephalopathies. This leukoencephalopathy appears to be a new distinct entity.