Cri du chat

Definition

Cri du chat syndrome occurs when a piece of chromosomal material is missing from a particular region on chromosome 5. Individuals with this syndrome have unusual facial features, poor muscle tone (hypotonia), small head size (microcephaly), and mental retardation. A classic feature of the syndrome is the catlike cry made by infants with this disorder.

Description

Dr. Jerome Lejeune first described cri du chat syndrome in 1963. The syndrome is named for the cat-like cry made by infants with this genetic disorder. Cri du chat means "cry of the cat" in French. This unusual cry is caused by abnormal development of the larynx (organ in the throat responsible for voice production). Cri du chat syndrome is also called "5p minus syndrome" because it is caused by a deletion, or removal, of genetic material from chromosome 5. The deletion that causes cri du chat syndrome occurs on the short or "p" arm of chromosome 5. This deleted genetic material is vital for normal development. Absence of this material results in the features associated with cri du chat syndrome.

A high-pitched mewing cry during infancy is a classic feature of cri du chat. Infants with cri du chat also typically have low birth weight, slow growth, a small head (microcephaly) and poor muscle tone (hypotonia). Infants with cri du chat may have congenital heart defects. Individuals with cri du chat syndrome have language difficulties, delayed motor skill development, and mental retardation. Behavioral problems may also develop as the child matures.

It has been estimated that cri du chat syndrome occurs in one of every 50,000 live births. According to the 5p minus Society, approximately 50–60 children are born with cri du chat syndrome in the United States each year. It can occur in all races and in both sexes.

— Holly Ann Ishmael, MS

(medicine) An inherited condition characterized by mental subnormality, physical abnormalities, and the emitting of a flat, toneless, catlike cry in infancy.

Clinical syndrome associated with the deletion of the short arm of a B chromosome. Manifestations include mental retardation, various congenital abnormalities, and an infant cry resembling the mewing of a cat.

Definition

Cri du chat (a French phrase that means "cry of the cat") syndrome is a group of symptoms that result when a piece of chromosomal material is missing (deleted) from a particular region on chromosome 5. Children born with this chromosomal deletion have a characteristic mewing cat-like cry as infants that is thought to be caused by abnormal development of the larynx (organ in the throat responsible for voice production). They also have unusual facial features, poor muscle tone (hypotonia), small head size (microcephaly), and mental retardation.

Description

Jerome Lejeune first described cri du chat syndrome in 1963. Cri du chat syndrome is also called 5p minus syndrome or chromosome 5p deletion syndrome because it is caused by a deletion, or removal, of genetic material from chromosome 5. The deletion that causes cri du chat syndrome occurs on the short or p arm of chromosome 5. This deleted genetic material is vital for normal development. Absence of this material results in the features associated with cri du chat syndrome.

A high-pitched mewing cry during infancy is a classic feature of cri du chat. Infants with cri du chat also typically have low birth weight, slow growth, a small head (microcephaly), and poor muscle tone (hypotonia). Infants with cri du chat may also have congenital heart defects, language difficulties, delayed motor skill development, scoliosis, and varying degrees of mental retardation. Behavioral problems such as hyperactivity may also develop as the child matures.

Demographics

It has been estimated that cri du chat syndrome occurs in one of every 50,000 live births. According to the 5p minus Society, approximately 50 to 60 children are born with cri du chat syndrome in the United States each year. The syndrome can occur in all races and in both sexes.

Causes and Symptoms

Cri du chat is the result of a chromosome abnormality—a deleted piece of chromosomal material on chromosome 5. In 90 percent of children with cri du chat syndrome, the deletion is sporadic. This means that it happens randomly and is not hereditary. If a child has cri du chat due to a sporadic deletion, the chance the parents could have another child with cri du chat is 1 percent. In approximately 10 percent of children with cri du chat, there is a hereditary chromosomal rearrangement that causes the deletion. If a parent has this rearrangement, the risk for their having a child with cri du chat is greater than 1 percent.

An abnormal larynx causes the unusual cat-like cry made by infants that is a hallmark feature of the syndrome. As children with cri du chat get older, the cat-like cry becomes less noticeable. This can make the diagnosis more difficult in older children. In addition to the catlike cry, individuals with cri du chat also have unusual facial features. These facial differences can be very subtle or more obvious. Microcephaly (small head size) is common. During infancy many children with cri du chat do not gain weight or grow normally. Approximately 30 percent of infants with cri du chat have a congenital heart defect. Hypotonia (poor muscle tone) is also common, leading to problems with eating and slow, but normal development. Mental retardation is present in all children with cri du chat, but the degree of mental retardation varies between children.

When to Call the Doctor

A doctor should be consulted if a child exhibits symptoms typical of cri du chat syndrome.

Diagnosis

During infancy, the diagnosis of cri du chat syndrome is strongly suspected if the characteristic cat-like cry is heard. If a child has this unusual cry or other features seen in cri du chat syndrome, chromosome testing should be performed. Chromosome analysis provides the definitive diagnosis of cri du chat syndrome and can be performed from a blood test. Chromosome analysis, also called karyotyping, involves staining the chromosomes and examining them under a microscope. In some cases the deletion of material from chromosome 5 can be easily seen. In other cases, further testing must be performed. Fluorescence in-situ hybridization (FISH) is a special technique that detects very small deletions. The majority of the deletions that cause cri du chat syndrome can be identified using the FISH technique.

Treatment

As of 2004, there is no cure for cri du chat syndrome. Treatment consists of supportive care and developmental therapy.

Prognosis

Individuals with cri du chat have a 10 percent mortality during infancy due to complications associated with congenital heart defects, hypotonia, and feeding difficulties. Once these problems are controlled, most individuals with cri du chat syndrome have a normal lifespan. The extent of mental retardation and other symptoms depends on the site of the chromosomal deletions, with larger deletions resulting in more serious symptoms. With extensive early intervention and special schooling, many cri du chat children can develop adequate social, motor, and language skills.

Prevention

As of 2004, cri du chat syndrome had no known prevention.

Parental Concerns

Cri du chat syndrome can be detected before birth if the mother undergoes amniocentesis testing or chorionic villus sampling (CVS). This testing would only be recommended if the mother or father is known to have a chromosome rearrangement, or if they already have a child with cri du chat syndrome.

Families may wish to seek counseling regarding the effects of the syndrome on relationships within the family. Many people respond with guilt, fear, or blame when a genetic disorder is diagnosed in the family, or they may overprotect the affected member. Support groups are often good sources of information about cri du chat syndrome; they can offer helpful suggestions about living with it as well as emotional support.

Resourcesbooks

Key, Doneen. Do You Want to Take Her Home?: Trials and Tribulations of Living Life as a Handicapped Person Due to Multiple Birth Defects. Lancaster, CA: Empire Publishing, 2001.

Moore, Keith L., et al. Before We Are Born: Essentials of Embryology and Birth Defects. Kent, UK: Elsevier—Health Sciences Division, 2002.

Organizations

5p- Society. 7108 Katella Ave. #502, Stanton, CA 90680. Web Site: www.fivepminus.org.

Alliance of Genetic Support Groups. 4301 Connecticut Ave. NW, Suite 404, Washington, DC 20008. Web site: www.geneticalliance.org.

Cri du Chat Society. Department of Human Genetics, Box 33, MCV Station, Richmond VA 23298. Telephone: 804/786-9632.

Cri du Chat Syndrome Support Group. Web site: www.cridchat.u-net.com.

National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. Web site: www.rarediseases.org.

Web Sites

"Cri du chat syndrome." Medline Plus. Available online at www.nlm.nih.gov/medlineplus/ency/article/001593.htm (accessed November 16, 2004).

[Article by: Judith Sims Holly Ann Ishmael, M.S.]

Cri du chat or Cri-du-chat
Classification and external resources
Facial features of a patient with Cri du Chat syndrome at age of 8 months (A), 2 years (B), 4 years (C) and 9 years (D)
ICD-10	Q93.4
ICD-9	758.31
OMIM	123450
DiseasesDB	29133
MedlinePlus	001593
eMedicine	ped/504

Cri du chat syndrome, also known as chromosome 5p deletion syndrome, 5p minus syndrome or Lejeune’s syndrome, is a rare genetic disorder due to a missing part of chromosome 5. Its name is a French term (cat-cry or call of the cat) referring to the characteristic cat-like cry of affected children. It was first described by Jérôme Lejeune in 1963.^[1] The condition affects an estimated 1 in 20,000 to 50,000 live births, strikes all ethnicities, and is more common in females by a 4:3 ratio.^[2]

Contents 1 Signs and symptoms 2 Genetics 3 Diagnosis and Management 4 References 5 External links

Signs and symptoms

The syndrome gets its name from the characteristic cry of affected infants, which is similar to that of a meowing kitten, due to problems with the larynx and nervous system. About 1/3 of children lose the cry by age 2. Other symptoms of cri du chat syndrome may include:

• feeding problems because of difficulty swallowing and sucking.
• low birth weight and poor growth.
• severe cognitive, speech, and motor delays.
• behavioral problems such as hyperactivity, aggression, tantrums, and repetitive movements.
• unusual facial features which may change over time.
• excessive dribbling.
• constipation.

Other common findings include hypotonia, microcephaly, growth retardation, a round face with full cheeks, hypertelorism, epicanthal folds, down-slanting palpebral fissures, strabismus, flat nasal bridge, down-turned mouth, micrognathia, low-set ears, short fingers, single palmar creases, and cardiac defects (eg, ventricular septal defect [VSD], atrial septal defect [ASD], patent ductus arteriosus [PDA], tetralogy of Fallot). People with Cri du chat are fertile and can reproduce.

Less frequently encountered findings include cleft lip and palate, preauricular tags and fistulas, thymic dysplasia, intestinal malrotation, megacolon, inguinal hernia, dislocated hips, cryptorchidism, hypospadias, rare renal malformations (eg, horseshoe kidneys, renal ectopia or agenesis, hydronephrosis), clinodactyly of the fifth fingers, talipes equinovarus, pes planus, syndactyly of the second and third fingers and toes, oligosyndactyly, and hyperextensible joints. The syndrome may also include various dermatoglyphics, including transverse flexion creases, distal axial triradius, increased whorls and arches on digits, and a (simian crease).

Late childhood and adolescence findings include significant intellectual disability, microcephaly, coarsening of facial features, prominent supraorbital ridges, deep-set eyes, hypoplastic nasal bridge, severe malocclusion, and scoliosis.

Affected females reach puberty, develop secondary sex characteristics, and menstruate at the usual time. The genital tract is usually normal in females except for a report of a bicornuate uterus. In males, testes are often small, but spermatogenesis is thought to be normal.

Genetics

Cri du chat syndrome is due to a partial deletion of the short arm of chromosome number 5, also called "5p monosomy". 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.

Most cases involve total loss of the most distant 30-60% of the material on the short arm. Fewer than 10% of cases have other rare cytogenetic aberrations (eg, interstitial deletions, mosaicisms, rings and de novo translocations). The deleted chromosome 5 is paternal in origin in about 80% of de novo cases.

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.

Diagnosis and Management

Diagnosis is based on the distinctive cry and accompanying physical problems. Genetic counseling and genetic testing may be offered to families with individuals who have cri du chat syndrome. Children may be treated by speech, sound, and occupational therapists. Cardiac abnormalities often require surgical correction.

References

1. ^ Lejeune J, Lafourcade J, Berger R, et al. (1963). "[3 Cases of partial deletion of the short arm of chromosome 5]" (in French). C. R. Hebd. Seances Acad. Sci. 257: 3098–102. PMID 14095841. 
2. ^ ped/504 at eMedicine

External links

• Australian Support Group
• United States Support Group
• United Kingdom Support Group
• A documentation in word and pictures: 21 years of living with the cri du chat-syndrome

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