Cri du chat Syndrome, chromosome 5p deletion syndrome, 5p minus syndrome or Lejeune’s syndrome
Cri du chat syndrome is a group of symptoms that result from deletion on chromosome number 5. The syndrome’s name is based on the infant’s cry, which is high-pitched and sounds like a cat.
It was first described by Jérôme Lejeune in 1963.
Approximately 90% of cases results from a sporadic, or randomly-occurring, de novo deletion. The remaining 10-15% are due to unequal segregation of a parental balanced translocation where the 5p monosomy is often accompanied by a trisomic portion of the genome. These individuals may have more severe disease than those with isolated monosomy of 5p.
Loss of a small region in band 5p15.2 (cri du chat critical region) correlates with all the clinical features of the syndrome with the exception of the catlike cry, which maps to band 5p15.3 (catlike critical region). The results suggest that 2 noncontiguous critical regions contain genes involved in this condition’s etiology. Two genes in these regions, Semaphorine F (SEMA5A) and delta catenin (CTNND2), are potentially involved in cerebral development. The deletion of the telomerase reverse transcriptase (hTERT) gene localized in 5p15.33 may contribute to the phenotypic changes in cri du chat syndrome as well.
- 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
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 show the deletion on chromosome 5.
Skull x-ray may reveal an abnormal angle to the base of the skull.