Van der Knaap disease: a rare disease with atypical features.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC), or Van der Knaap disease, is a rare autosomal recessive disorder. It is characterised by macrocephaly that either presents at birth or develops during infancy. It occurs more commonly in some ethnicities where consanguinity is common, such as in the Agrawal community in India. This disease typically presents with a history of delayed motor milestones in affected children. MRI findings including leukodystrophy and subcortical cysts are hallmarks of the disease and yield the diagnostic clue in most cases. Several cases of Van der Knaap disease with classical features have been reported in the literature. We present a case of Van der Knaap disease with classical MRI features, including a few distinctly atypical characteristics in its epidemiological, clinical and electrophysiological attributes. 2015 BMJ Publishing Group Ltd.