In the developing brain, HLD7-associated mutations of POLR3A proteins appear to be linked to their decreased transcription abilities for rRNAs and tRNAs and/or downregulation of their expression, leading to insufficient transcription and in turn insufficient translation of many target molecules, especially for myelin-related molecules [9,10]. This evidence concerns the gene POLR3A and leukodystrophy, hypomyelinating, 7, with or without oligodontia and/or hypogonadotropic hypogonadism.