Cri du Chat Syndrome, also known as 5p- Syndrome is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, distinctive facial features, small head size, low birth weight, and low muscle tone in infancy. Some children with Cri du Chat Syndrome are also born with heart defect.