POLR3A and hypogonadotropic hypogonadism: The classical form is characterized by the association of hypomyelination, abnormal dentition, and hypogonadotropic hypogonadism, but the recent identification of two genes (POLR3A and POLR3B) responsible for the syndrome demonstrates that these three main characteristics can be variably combined among “Pol-III (polymerase III)-related leukodystrophies.”