Cri-du-chat syndrome

Cri-du-chat syndrome is caused by a deletion of part of chromosome number 5, meaning that a piece of the chromosome, and the genes that part of the chromosomes contains, are missing. Genetic information is organized in our cells on structures called chromosomes. Most cells in the body typically contain 46 chromosomes, which are organized into 23 pairs of 2. Babies inherit one of each pair of chromosomes from each of their parents in the egg and sperm cells.

Individuals with Cri-du-chat syndrome are missing a piece of one of their two chromosome number 5s. The other chromosome 5 is typically intact. However, having the deletion (missing piece of chromosome) on one of the two copies of chromosome 5 present in the cells is sufficient to cause the health and developmental problems seen in Cri-du-chat syndrome (known as autosomal dominant inheritance). Having only one copy of the genetic information typically found on that part of chromosome number 5, instead of the typical two, causes an imbalance of genetic information in the body, which leads to the health and developmental problems people with Cri-du-chat syndrome may have.

No, there is nothing that makes the symptoms of Cri-du-chat syndrome worse. However, an affected child's development can be maximized with help from an early age, such as physical, occupational, and speech therapy.

Not all individuals with Cri-du-chat syndrome are affected in exactly the same ways or have all of the characteristics described with Cri-du-chat syndrome.

Deletion (missing piece) of a specific region near the end of chromosome 5 causes Cri-du-chat syndrome. No other factor is necessary in order to be affected with Cri-du-chat syndrome.