POLR3B and leukodystrophy: Similar to what is observed in cases with the disease caused by mutations in POLR3A or POLR3B, clinical and radiological characteristics of these eight cases were compatible with POLR3-related leukodystrophy; however, patients did not necessarily have all clinical (that is, neurological, dental, ophthalmological and endocrine abnormalities) and MRI features1, 3, 12 (Table 1, Fig. 2, Supplementary Tables 4 and 5) of the disease.