Cri du chat syndrome

Alternative names

Chromosome 5p deletion syndrome; 5p minus syndrome; Cat cry 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.

Causes, incidence, and risk factors

The cri du chat syndrome is caused by the deletion of information on chromosome 5. 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 cri cu chat develop.

The cause of this rare chromosomal deletion is not known, but it is expected that the majority of cases are due to spontaneous loss of a piece of chromosome 5 during 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 and 1 in 50,000 babies are affected. This disease may account for up to 1% of individuals with severe mental retardation. Infants with cri du chat syndrome commonly have a distinctive cat-like cry. They also have an extensive grouping of abnormalities with severe mental retardation being the most important.

Symptoms

• high-pitched cry sounds like a cat (for which the syndrome was named)
  
• low birth weight and slow growth
  
• small head (microcephaly)
  
• wide-set eyes (hypertelorism)
  
• downward slant to the eyes (palpebral fissures)
  
• small jaw (micrognathia)
  
• low-set ears (may be malformed)
  
• skin tags just in front of the ear
  
• partial webbing or fusing of fingers or toes
  
• single line in the palm of the hand (simian crease)
  
• mental retardation
  
• slow or incomplete development of motor skills
  

Signs and tests
In addition to the other findings (listed with Symptoms), 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