What are the other Names for this Condition? (Also known as/Synonyms)

• 5p Deletion Syndrome
• Cat-Cry Syndrome
• Chromosome 5 Short Arm Deletion Syndrome

What is Cri du Chat Syndrome? (Definition/Background Information)

• Cri du Chat Syndrome is characterized as a rare genetic anomaly that occurs due to the random deletion of a part of Chromosome 5, during the formation and development of a reproductive cell (either the sperm cell or the egg cell)
• This defect is carried forward into the fertilization and development stage of an embryo, leading ultimately to the manifestation of mental and physical disabilities in the child
• Cri du Chat Syndrome is also known as the Crying Cat Syndrome, due to the typical high-pitched cat-like cry or meow of the babies
• Both prenatal and postnatal methods are available to diagnose the condition
• Medical therapy and surgical procedures are generally used to treat the condition; however, the prognosis is grim

Who gets Cri du Chat Syndrome? (Age and Sex Distribution)

• The estimated incidence of Cri du Chat Syndrome is about 1 in 50,000 live births
• However, this genetic disorder is more frequently seen in females than males, by a factor of 4:3
• Cri du Chat Syndrome affects all races and ethnic groups

What are the Risk Factors for Cri du Chat Syndrome? (Predisposing Factors)

Risk factors of Cri du Chat include:

• Genetic defect: The condition may be transmitted in a genetic manner and this could be a risk factor
• It has been observed that female babies are affected slightly more than the male babies, putting them at a slightly higher risk for Cri du Chat Syndrome

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Cri du Chat Syndrome? (Etiology)

Cri du Chat Syndrome is also termed as ‘Deletion of Short Arm of Chromosome 5 Syndrome’. Generally, a chromosome has two parts, namely, the short arm of the chromosome and the long arm of the chromosome. ‘Short arm deletion’ is the medical term used to describe the condition, when a piece of the short arm of the chromosome is missing. This leads to developmental abnormalities and complications in the fetus.

• It is supposed that this chance event occurs, when the egg or sperm cell forms. This cell, then takes part in the fertilization process and the genetic defect is carried forward, into the developing fetus
• Since a portion of the chromosome is lost, some vital information that is contained in those genes is also lost. This causes clinical signs and symptoms seen in the syndrome and genetic malformations
• However, it is observed that not all Cri du Chat cases occur, as described above. About 10% of them take place when an altered and unequal chromosomal arrangement (of chromosome 5), is passed on from the parent to their offspring. In such cases, the severity of the signs and symptoms observed in disorder is found to be even more intense

What are the Signs and Symptoms of Cri du Chat Syndrome?

The most striking feature of Cri du Chat Syndrome is the affected infant’s cat-like cry. Normally, feeding problems are encountered because the baby has difficulty suckling or in swallowing milk. These issues, accompanied by other physical signs and symptoms, are telltale indicators for the physician.

In a newborn, the following signs and symptoms may be additionally noted:

• Low birth weight
• Abnormally featured ears and eyes
• Fused fingers and toes
• Small head and jaw
• Heart-related defects

As the child grows, the following are noted apart from the other physical defects:

• Mental retardation
• Slow motor skills
• Behavioral issues (hyperactivity, violent nature, insecurity-related issues)
• Speech and learning problems

In adolescence: The reproductive health and development of both male and female sex may be affected. This may result in the abnormal development of male and female sexual characteristics. However, despite these developmental changes, the fertility of the child is not affected

How is Cri du Chat Syndrome Diagnosed?

A diagnosis of Cri du Chat Syndrome would involve:

• Physical exam and evaluation of family medical history - the distinct crying sound accompanied by other typical physical features, may be noted by the physician. The physical exam may also reveal:
  • A bulge in the groin region (inguinal hernia)
  • Weak muscles that may be observed all over the body
  • Separated belly muscle, due to weak and abnormal development of the abdominal muscles, resulting in a condition called abdominal diastasis. In the region of the separated belly muscles, the internal organs of the abdomen may protrude out
• X-ray study of the skull, in order to check for abnormalities in the skull bones
• Prenatal genetic testing is available to detect Cri du Chat Syndrome, from a sample of the amniotic fluid or chorionic villi

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Cri du Chat Syndrome?

• The complications of Cri du Chat could be mild or severe, depending on the severity of the physical conditions and mental disabilities
• Cri du Chat Syndrome has a host of physical and structural cranial (head) abnormalities; disorders that develop during the formation of the fetus in the mother’s womb (in vitro development)
• Nevertheless, it has mostly been observed that the fertility of the individual is not affected

How is Cri du Chat Syndrome Treated?

The treatment measures for Cri du Chat may include the following:

• The shrill cat-like cry might disappear after a while, in some cases, before the age of two
• Some of the physical defects can be corrected, and surgical procedures performed (such as cardiac surgery for cardiac abnormalities)
• For improving other motor skills and mental disabilities, special therapeutic treatment (by speech, occupational therapists), behavior modification programs, and supportive care, may have to be provided

A case-by-case, long-term treatment approach is generally undertaken by the physician in consultation with the parents/family members. It has to be understood that a specific course of treatment cannot be modeled for Cri du Chat Syndrome.

How can Cri du Chat Syndrome be Prevented?

• Currently, there are no specific methods or guidelines to prevent Cri du Chat Syndrome genetic condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for  treatment and prevention of inherited and acquired genetic disorders

What is the Prognosis of Cri du Chat Syndrome? (Outcomes/Resolutions)

• Most of the deaths occur, before and during, the first year of birth of the child (about 90%)
• Individuals, who survive the first few years, have lower mortality rates (about 10%)
• With early diagnosis and continuous treatment, the burden of the disorder can be decreased
• Individuals may have a favorable outcome through intense treatment measures, support and rehabilitation, which may result in better social adaptability, communication skills, and greater independence

Additional and Relevant Useful Information for Cri du Chat Syndrome:

There are voluntary organizations and support groups that provide help and understanding to the Cri du Chat Syndrome affected children and their parents.