Up to date etiopathogenetic knowledge of phakomatoses allows a more rational classification as compared to the known ones, based on anatomopathological and/or clinical features. Some genes have been identified, which are correlated with neurofibromatoses, tuberous sclerosis and other conditions, through general biologic mechanisms (derivatives of the embryonic neural crest; nerve growth factor and its receptor; oncogenes and antioncogenes, etc.). A prenatal predictive value from those genetic connections can also ensue. The new diagnostics, both by imaging and by laboratory techniques, may affect the therapeutic choices, as for as urological involvement is concerned.