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The characteristic cry of Cri Du Chat syndrome is present during the first weeks of life. Birth weight is usually low, and growth is slow. Almost all infants with Cri Du Chat Syndrome have an abnormally small head (microcephalic) and mental retardation. There is significant speech delay. Attention deficit and hyperactivity are very common. An infant with this disorder generally has a round face with unusually wide-set eyes (hypertelorism), and excess skin over the inner corners of the eyes (epicanthal folds). Other symptoms of Cri du Chat syndrome may include eyes that are either crossed or looking away (strabismus), low-set and/or malformed ears, a small chin, a prominent nose, and facial features that are not balanced side to side (asymmetry). A single crease across the palms of the hands (Simian creases) is common. Over three-quarters of these infants have signs of weakness and poor muscle tone (hypotonia). As the infants grow older this is generally replaced with an exaggeration of muscular reflexes (hyperreflexia). A few patients with Cri Du Chat Syndrome are nearsightedness (myopia).

Some infants with Cri Du Chat Syndrome may have a split in the front of the upper lip (cleft lip), an abnormal opening in the roof of the mouth (cleft palate), or an abnormal opening or fissure in the back of the mouth (bifid uvula). In some patients, one side of the spinal column may be incompletely developed (hemivertebra). Other infants may have a tear in the supportive tissue of the lower abdomen (inguinal hernia). In male infants with Cri Du Chat syndrome the testes may fail to descend into the scrotum (cryptorchidism). Other infrequent symptoms include the absence of a kidney and/or the spleen, a clubfoot, and flat feet. Seven of 13 adults in one study had a curvature of the spinal column (scoliosis) and 11 patients had short bones in the hands (metacarpals) and feet (metatarsals).

Cri Du Chat Syndrome is caused by a partial deletion of the short arm (p) of chromosome 5. Chromosomes, which are present in the nucleus of human cells, carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males, and two X chromosomes for females. Each chromosome has a short arm designated as "p" and a long arm identified by the letter "q." Chromosomes are further sub-divided into many bands that are numbered. For example, "chromosome 11p13" refers to band 13 on the short arm of chromosome 11.

Cri du Chat Syndrome was first described in 1963; since then over 100 cases have been reported. It has been estimated that the syndrome occurs in about one out of 20,000 births and accounts for approximately one percent of institutionalized mentally retarded patients.

Treatment for Cri du Chat Syndrome is symptomatic and supportive. Physical therapy, special education and related services may be of benefit to children. Surgery may be performed to correct an eye that is either crossed or looking away (strabismus) and this may offer some cosmetic improvement. An orthopedist should be consulted for curvature of the spine (scoliosis) and deformities of the feet.

A series of surgeries may correct a cleft lip and palate. Speech therapy may be necessary in some cases. Early preventive dental treatment in an aggressive manner is very important; the dentist must be informed that the patient has Cri du Chat Syndrome.

Genetic counseling may be of benefit for patients and their families.

Research and studies of Cri du Chat Syndrome are ongoing. One study has shown that early special schooling, a home environment (rather than an institutional one), and family support may help the patient achieve the abilities of a normal five or six year old. In the same study half the children over ten who had undergone special schooling and lived in a supportive home environment, were able to communicate adequately.

Scientific techniques in determining chromosomal abnormalities are becoming more and more refined. This means diagnostic techniques have improved and in certain instances prenatal diagnosis of Cri du Chat Syndrome is possible.

Research on birth defects and their causes is ongoing. The National Institutes of Health (NIH) is sponsoring the Human Genome Project which is aimed at mapping every gene in the human body and learning why they sometimes malfunction. It is hoped that this new knowledge will lead to prevention and treatment of genetic disorders in the future.

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5p;12q TRANSLOCATION WITH MANIFESTATIONS OF CRI DU CHAT SYNDROME AND MARFANOID ARACHNODACTYLY. S.Z. Zhang et al.; Clin Genet (Feb 1990; 37(2)). Pp. 153-57.

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