Leukodystrophies comprise a large group of rare genetic disorders primarily affecting CNS white matter. Historically, the diagnostic process was slow and patient prognosis regarded as poor because curative treatment was only available for very few leukodystrophies in early stages of the disease. Whole-exome sequencing has both greatly increased the number of known leukodystrophies and improved diagnosis. Whether MRI keeps its central place in diagnosis and what the role is of whole-exome sequencing are relevant questions for neurologists. Improved diagnosis has revealed the phenotypic variability of leukodystrophies, requiring adaptation of prognostication. Technological advance in molecular techniques and improved insight into the pathophysiology of individual leukodystrophies have led to therapeutic developments, including drug design and gene therapy. Despite this progress, therapies are only beneficial early in the disease course, emphasising the need for a speedy diagnosis and for research on regenerative approaches to repair the damage already present.