[Hair with a double crown and dilatation of Virchow-Robin spaces: a proposal for a new neurocutaneous association].

Introduction: The primitive ectoderm is the common origin of the nervous system, the skin and related organs. These structures can therefore be affected simultaneously by aggressions that take place during embryogenesis involving the ectodermal layer. To date multiple neurocutaneous associations have been reported, some of which were catalogued as genetically determined syndromes or diseases.