PTEN and Alexander disease: Within the group of neurodegenerative diseases with macrocephaly, developmental delay, affected brain white matter and visual problems, CD needs to be distinguished from genetic encephalopathies such as GM1 or GM2 gangliosidosis, PTEN (Phosphatase and tensin homolog protein diseases), megalencephalic leukoencephalopathy with subcortical cysts, Alexander disease or glutaric aciduria.