Cri du chat syndrome is a rare genetic condition that is caused by the deletion (a missing piece) of genetic material on the small armof chromosome 5. The cause of this rare chromosomal deletion is unknown.
The symptoms of cri du chat syndrome vary among individuals. The variability of the clinical symptoms and developmental delays may be related to the size of the deletion of the 5p arm.
The clinical symptoms of cri du chat syndrome usually include a high-pitched cat-like cry, mental retardation, delayed development, distinctive facial features, small head size (microcephaly), widely-spaced eyes (hypertelorism), low birth weight and weak muscle tone (hypotonia) in infancy. The cat-like cry typically becomes less apparent with time.
Most individuals who have cri du chat syndrome have difficulty with language. Half of children learn sufficient verbal skills to communicate. Some individuals learn to use short sentences, while others express themselves with a few basic words, gestures, or sign language.
Other characteristics may include feeding difficulties, delays in walking, hyperactivity, scoliosis, and significant retardation. A small number of children are born with serious organ defects and other life-threatening medical conditions, although most individuals with cri du chat syndrome have a normal life expectancy.
Both children and adults with this syndrome are usually friendly and happy, and enjoy social interaction.
The diagnosis of cri du chat syndrome is generally made in the hospital at birth. A health care provider may note the clinical symptoms associated with the condition. The cat-like cry is the most prominent clinical feature in newborn children and is usually diagnostic for the cri du chat syndrome.
No specific treatment is available for this syndrome. Children born with this genetic condition will most likely require ongoing support from a team made up of the parents, therapists, and medical and educational professionals to help the child achieve his or her maximum potential. With early and consistent educational intervention, as well as physical and language therapy, children with cri du chat syndrome are capable of reaching their fullest potential and can lead full and meaningful lives.
Most cases of cri du chat syndrome is not inherited. The chromosomal 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 inherits 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.