Cri-Du-Chat Syndrome

What is cri-du-chat syndrome?

Cri-du-chat (cat's cry) 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 also characterised by mental retardation and delayed development, distinctive facial features, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy.

How common is cri-du-chat syndrome?

Cri-du-chat syndrome occurs in an estimated 1 in 20,000 to 50,000 newborns. This condition is found in people of all ethnic backgrounds and is slightly more common in females.

What are the genetic changes related to cri-du-chat syndrome?

Cri-du-chat syndrome is a chromosomal condition related to chromosome 5.

Cri-du-chat syndrome is caused by a deletion of the end of the short (p) arm of chromosome 5. This chromosomal change is written as 5p-. The signs and symptoms of cri-du-chat syndrome are probably related to the loss of multiple genes in this region. Researchers have not yet identified all of these genes or determined how their loss leads to the features of the disorder. They have discovered, however, that a larger deletion tends to result in more severe mental retardation and developmental delay in people with cri-du-chat syndrome.

Can cri-du-chat syndrome be inherited?

Most cases of cri-du-chat syndrome are not inherited. They result from a chromosomal deletion that occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. Affected people typically have no history of the disorder in their family.

About 10 percent of people with cri-du-chat syndrome inherit the chromosome with a deleted segment from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which no genetic material is gained or lost. Balanced translocations usually do not cause any medical problems; however, they can become unbalanced as they are passed to the next generation. A deletion in the short arm of chromosome 5 is an example of an unbalanced translocation, which is a chromosomal rearrangement with extra or missing genetic material. Unbalanced translocations can cause birth defects and other health problems such as those seen in cri-du-chat syndrome.

What other names do people use for cri-du-chat syndrome?

  • Cat cry syndrome
  • Chromosome 5p- Syndrome
  • 5p Deletion Syndrome
  • 5p- Syndrome

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