5p minus syndrome

Definition

Cri du chat syndrome is a group of symptoms that result from missing a piece of chromosome number 5. The syndrome's name is based on the infant's cry, which is high-pitched and sounds like a cat.

Alternative Names

Causes

Cri du chat syndrome is rare. It occurs when a piece of information on chromosome 5 is missing. It is likely that multiple genes on chromosome 5 are deleted. One deleted gene, called TERT (telomerase reverse transcriptase) is involved in control of cell growth, and may play a role in how some of the features of this syndrome develop.

Most cases are believed occur during the development of an egg or sperm. A minority of cases result from one parent carrying a rearrangement of chromosome 5 called a translocation.

Between 1 in 20,000 - 50,000 babies are affected. This disease may account for up to 1% of individuals with severe mental retardation.

Symptoms

• Cry that is high-pitched and sounds like a cat
• Downward slant to the eyes
• Low birth weight and slow growth
• Low-set or abnormally shaped ears
• Mental retardation
• Partial webbing or fusing of fingers or toes
• Single line in the palm of the hand (simian crease)
• Skin tags just in front of the ear
• Slow or incomplete development of motor skills
• Small head (microcephaly)
• Small jaw (micrognathia)
• Wide-set eyes

Exams and Tests

In addition to symptoms, the physical examination may show:

• Inguinal hernia
• Diastasis recti (separated abdominal muscles)
• Low muscle tone
• Epicanthal folds, an extra fold of skin over the inner corner of the eye
• Incompletely or abnormally folded external ears

Genetic tests can show a missing part of chromosome 5. Skull x-ray may reveal an abnormal angle to the base of the skull.

Treatment

No specific treatment is available for this syndrome. The mental retardation must be addressed, and counseling is recommended for the parents.

Parents of a child with this syndrome should have genetic counseling and a karyotype test to determine if one parent has a rearrangement of chromosome 5.

Support Groups

5p- Society -- www.fivepminus.org

Outlook (Prognosis)

The outcome varies but mental retardation is usual. Half of those children affected learn sufficient verbal skills to communicate. The cat-like cry becomes less apparent over time.

Possible Complications

Complications depend on the extent of mental retardation and physical abnormalities. Complications may include:

• Inability to care for self
• Inability to function in society

When to Contact a Medical Professional

This is a diagnosis that is generally made in the hospital at birth. Your health care provider will discuss the findings with you. On discharge, it's important to maintain regular contact with your health care provider and other caregivers. Genetic counseling and testing is recommended for all persons with a family history of this syndrome.

Prevention

There is no known prevention. Couples with a family history of this syndrome who wish to become pregnant may consider genetic counseling.

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