Cri u Chat syndrome or Cri-du-Chat syndrome (French for Cry or call of the cat referring to the specific cry of the child), also called deletion 5p syndrome, 5p minus or Lejeune’s syndrome, is a rare genetic disorder due to a missing portion of chromosome 5. It was first described by Jérôme Lejeune in 1963. The condition affects an estimated 1 in 20,000 to 50,000 live births. The disorder is found in people of all ethnic backgrounds and is more common in females by a 3-1 ratio.