What is Cri Du Chat Syndrome?

 

Cri du chat syndrome occurs when a piece of chromosomal material is missing from the short arm on chromosome 5. This segment is vital for normal development, and in its absence, a person will develop the features typical of cri du chat. Others names for the disorder include "cat cry syndrome" or chromosome deletion 5p syndrome. People with this syndrome have unusual facial features, poor muscle tone, small head size, and possible mental retardation. A classic feature of the syndrome is the cat-like cry made by infants with this disorder. The condition affects only an estimated 1 in 20,000 to 50,000 births each year. The disorder is found in people of all ethnic backgrounds but is more common in females than males shown by the 3:1 ratio of those affected. Most people affected with the disease have a normal lifespan, however some die early on.

 

The disease was first named in 1963 by Dr. Jerome Lejeune, a French geneticist and professor at Rene Descartes University in Paris. He called it "cri du chat," French for "cry of the cat." Before the 1980's, parents were encouraged to institutionalize children with cri du chat, for their prognosis was not very bright. They were not offered the education or therapy necessary for living a long and fulfilling life. After more research was conducted regarding the disease, therapies and programs were developed to help those with cri du chat, or CDCS.

 

 

 

 

 

 

 

 

                                 `                         Karyotpe of someone with Cri Du Chat Syndrome. Note the deletion on the #5 chromosome.

 

 

 

Causes

CDCS is the result of a missing segment on chromosome 5. The disease is neither autosomal or sex-linked, rather the majority of deletions are new mutations. In about 80% of patients, the defective chromosome comes from the father. In about 90% of patients, the deletion is random and not hereditary. In approximately 10% of patients with cri du chat, there is a hereditary chromosomal rearrangement that causes the deletion. If a parent has this rearrangement, the risk for them to have a child with cri du chat is greater than 1%. The greater amount of the segment missing from chromosome 5 determines the severity of the symptoms.

 

 

 

Symptoms

 

The most identifiable symptom is the infant's mewing cry (hence the name "Cry of the Cat"), due to defects with the larynx and nervous system. The cry becomes less and less noticeable as the child ages, and is most often lost by age two.

CLICK HERE to hear cri du chat baby cry

Other symptoms include:

• difficulty swallowing and sucking leads to feeding problems
• low birth weight 
• severe cognitive, speech, and motor impairments
• behavioral problems including hyperactivity and tantrums
• repetitive movements 
• unusual facial features 
• wide-set eyes with a downward slant
• low-set ears with a skin tag in front
• flat nasal bridge                                                                                                                                                                                                                                                  
• short fingers
• growth retardation 
• problems sleeping
• cardiac problems

 

 

 

Diagnosis

 

During infancy, the diagnosis of cri du chat syndrome is strongly suspected if the characteristic cat-like cry is heard. If a child has this unusual cry or any of the other features seen in cri du chat syndrome, chromosome testing should be performed. Karyotyping (Chromosome analysis) will provide the official diagnosis of cri du chat syndrome and can be performed through a blood test. Karyotyping involves staining the chromosomes and examining them under a microscope. In some cases the deletion of material from chromosome 5 can be easily seen. In other cases more testing must be performed. FISH (fluorescence in-situ hybridization) is a special technique that detects very small deletions. The majority of the deletions that cause cri du chat syndrome can be identified using the FISH technique.

 

OR

 

 

Cri du chat syndrome can be detected before birth if the mother undergoes amniocentesis testing or chorionic villus sampling (CVS). This testing would only be recommended if the mother or father is known to have a chromosome rearrangement, or if they already have a child with cri du chat syndrome.

 

 

Treatment

 

 As of now there is no cure for cri du chat syndrome. Treatment consists of supportive care and developmental therapy. Behavioral modification therapy has been found to be useful to control head-banging, hyperactivity, and other behavioral problems that emerge during later childhood. It is recommended that parents seek help through support groups (see support groups below). People with CDCS can still live a relatively normal and happy life. While extra care is needed for individuals affected with the disorder, they can still gain independence and maintain jobs in adulthood. It is found that most people with the disease have a normal life span. As far as schooling is concerned, most are given special education. There are not many cases in which an individual attends mainstream schools.

 

 

Support Groups

 

 When a child is diagnosed with cri du chat, the family is often recommended to join a support group. Support groups (usually hosted on the Internet) outline the symptoms and milestones of the syndrome. Advice is given on certain topics such as feeding, behavioral and developmental issues, and education for the child. Different groups usually hold an annual conference for families affected by cri du chat. Web sites include forums for families to connect to each other and cope with the disease. They also provide information on socialization for the child. People may post biographies and pictures of their cri du chat child.

 

Several Cri Du Chat Support Groups:

 

 

 

 

 

 

                                  A picture of chromosome five, displaying the segment that causes cri du chat when absent.

 

 

 

Individuals affected with CDCS.

 

 

Works Cited:

 

 

Campbell, Dennis J., Ph.D., et al. "Cri-du-Chat Syndrome: A Topical Overview." 5p Minus Society.  2004. 20 Apr. 2008  <http://www.fivepminus.org/cdc%20overview.pdf>. 
 

 

 

Ishmael, Holly. "Cri du Chat Syndrome." Gale Encyclopedia of Genetic Disorders, 2^nd ed. Gale. 8 Apr. 2008 <http://infotrac.galegroup.com/itweb/?db=GVRL>.

 

McKusick, Victor A. "123450 Cri-du-Chat Syndrome." National Center for Biotechnology Information. 4 Jan. 2007. National Institutes of Health. 20 Apr. 2008 <http://www.ncbi.nlm.nih.gov/entrez/ 
 

     dispomim.cgi?cmd=entry&id=123450>. 
 

 

 

http://www.ucl.ac.uk/~ucbhjow/bmsi/lec7_images/5p-k.jpg

 http://en.wikipedia.org/wiki/Cri_du_chat

 

 

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Amanda Devine                                           Lindsey Bissinger

 

 

 

 

 

 

 

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