Symptomes

Causes & symptoms
The deletion on chromosome 5 has several indicators. The primary sign is an infant's high-pitched mewing cry during the first weeks of life. This unusual cry is accompanied by low birth weight, slow growth, and a small head (microcephaly). Muscle tone is poor (hypotonia) and possible medical problems include heart disease and scoliosis (curvature of the spine). Children with cri du chat syndrome have language difficulties, delayed motor skill development, and mental deficiencies that vary in severity. Behavioral problems, such as hyperactivity, may become apparent as the child matures.

Diagnosis
The key indicator of cri du chat syndrome is the characteristic catlike cry of an infant. As the child matures, this typical sound is lost. A definitive diagnosis is based on karyotyping. This laboratory procedure involves separating the chromosomes from a sample of the infant's cells. The chromosomes are then stained and examined under a microscope. The stain makes changes in the expected appearance of chromosome 5 noticeable and demonstrates that genetic material is missing. Cri du chat syndrome can be detected before birth if the mother undergoes amniocentesis testing or chorionic villus sampling. The samples of cells are collected from the fluid surrounding the fetus and are analyzed for genetic defects (amniocentesis test) or from the outer membrane (chorion) of the sac that holds both the fetus and the fluid (chorionic villus sampling test).