In 2014, Wolf et al. published a multinational cross-sectional observational study on the clinical, molecular, and MRI characteristics of 105 patients with mutation-proven 4H leukodystrophy caused by mutations in POLR3A or POLR3B. A total of 62 patients had mutations in the POLR3B gene [21]. Here, POLR3A is linked to leukodystrophy.