Sisters with clinically mild encephalopathy with a reversible splenial lesion (MERS)-like features; Familial MERS?

We first report sisters presenting with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS)-like features, i.e., mild and reversible neurological manifestations, and MRI finding of a reversible lesion with transiently reduced diffusion in the corpus callosum associated with symmetrical white matter. The distributions of the white matter lesions (more extensive) and Na levels (normal) were different from those reported for sporadic MERS patients (subcortical white matter close to the central sulci, and hyponatremia), which suggested that the pathophysiology of the sisters with MERS-like features might be different from that of sporadic MERS. Some genetic factors might be involved in MERS, especially in some patients with extensive white matter lesions.