Cri du chat syndrome also known as 5p syndrome and cat cry syndrome - is a rare genetic condition that is caused by the deletion (a missing piece) of genetic material on the small arm of chromosome 5. Cri du Chat is a genetic disorder first described and named in 1963 by Jerome Lejeune. Cri-du-Chat means "cat's cry" in French. The disorder causes the baby to produce a high pitched and cat like cry because of the structural abnormality and low muscle tone. It usually becomes less noticeable as the baby gets older, making it difficult for doctors to diagnose cri du chat after age two.
Type of Genetic Abnormality
The syndrome is caused by a deletion on the short arm of chromosome five. A number of genes are missing due to the deletion, and each can contribute to the symptoms the child experiences. One of the deleted genes that is known to be involved is referred to as ‘TERT’ or telomerase reverse transcriptase, which is important during cell division because it assists in keeping the tips of chromosomes in tact. Most cases of cri du chat syndrome are not inherited. The chromosome deletion usually occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. People with cri du chat typically have no history of the condition 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. The deletion is caused by a break in the DNA molecule that makes up a chromosome. As I already said in most cases, the chromosome break occurs while the sperm or egg cell (the male or female gamete) is developing. When this gamete is fertilized, the child will develop Cri Du Chat syndrome. The parent, however, does not have the...