The deletion that causes cri du chat syndrome occurs on the short or p arm of chromosome 5.
Absence of this material results in the features associated with cri du chat syndrome.
A high-pitched mewing cry during infancy is a classic feature of cri du chat.
Infants with cri du chat also typically have low birth weight, slow growth, a small head (microcephaly), and poor muscle tone (hypotonia).
Infants with cri du chat may also have congenital heart defects, language difficulties, delayed motor skill development, scoliosis, and varying degrees of mental retardation.
