Cri du Chat Syndrome

What is Cri du Chat Syndrome?

Cri du chat syndrome is a genetic condition also known as cat’s cry or 5P minus (5P-) syndrome.  It is a deletion of the short arm of chromosome 5. The condition is quite rare, occurring in about 1 in 20,000-50,000 newborns. This means that about 20 to 50 babies are affected in the USA every year. Cri-du-chat means the “cry of the cat” in French. Infants with this syndrome produce a high-pitched cry that sounds like a cat. This is due to the abnormal development of the larynx due to chromosome deletion, which affects the child’s cry. The syndrome is more noticeable as the child continues to grow but is difficult to diagnose past the age of 2. The syndrome comes with many abnormalities and disabilities as well. 

A small percentage of affected infants are born with severe organ defects (especially heart or kidney defects) or other serious complications that often result in death. Most of the fatal complications usually occur before the child reaches the first birthday. Children with the syndrome who pass the age of 1 will generally have a normal life expectancy. The child will most likely suffer from lifelong physical or developmental complications, which are usually dependent on the severity of the syndrome. About half of the children with the syndrome can learn enough words to communicate. They can grow up to be happy, friendly and sociable.

What are the symptoms of cri-du-chat syndrome?

The symptoms seen in the syndrome can differ from case to case. The most common symptom is the distinct high-pitched, shrill cry that sounds like a cat, which may be noticed in the first few weeks of the baby’s life. The cry becomes less noticeable as the baby grows older. The baby may also have distinct facial features which include:

• An abnormally round face
• Crossed eyes
• Unusually small head
• Wide nose
• Downward slanting eyes
• Abnormally small jaw
• Low-set ears
• Extra fold of skin over the inner corner of the eyes of the child
• An unusually short distance from the child’s upper lip to their nose

The face may lose the plumpness and become abnormally long and narrow as the baby grows. Other symptoms may include:

• Delayed growth
• Low birth weight 
• Scoliosis
• Heart defects
• Developmental delays
• Feeding difficulties
• Moderate to severe intellectual disability
• Speech and language delays

What is the cause of cri du chat syndrome?

The syndrome is a chromosomal disorder. It is caused by the deletion of part of the short arm of chromosome 5. The deletion usually occurs randomly during the formation of reproductive cells in early fetal development. The parents of the child with the random deletion usually have normal chromosomes. Most cases of the syndrome are not inherited, meaning it is neither a dominant nor recessive trait. There is usually no biological family history of the disorder in people with the syndrome. Some of the affected people, about 10%, inherit the chromosome abnormality from an unaffected parent. When this happens, the parent carries a chromosomal rearrangement called balanced translocation. The parent does not gain any genetic material, and they do not usually have any medical problems. However, balanced translocations can become unbalanced when a parent passes them on to their child. 

Can the syndrome be prevented?

There is no way to prevent it since it is a genetic condition. However, genetic counselling can help expecting parents understand the risks of having a child with a genetic condition.

What is the diagnosis of cri du chat syndrome?

The healthcare provider will usually be able to diagnose cri du chat syndrome at birth. They will be able to see and hear the symptoms that are associated with the disease including the cat-like cry. A physical examination will be completed, and the symptoms evaluated. A chromosomal test will also be recommended to confirm the diagnosis. Three genetic tests may be used to diagnose cri du chat syndrome. They are:

• Karyotype– This is a chromosomal analysis that maps out the child’s chromosomes and indicates if something is missing or added.
• FISH Testing – This means fluorescence in situ hybridization, and it looks for specific gene changes or parts of genes in the child’s cells
• Chromosome microarray analysis – This is a type of genetic testing that compares the child’s DNA to a control group. It can detect deletions and duplications of entire chromosomes, chromosome segments, and specific chromosomal locations. 

Is there any treatment for cri du chat?

While there is no cure for the syndrome, however with early diagnosis and intervention, the affected child may be capable of reaching their potential and achieving a meaningful life. The treatment can vary depending on the specific symptoms exhibited by the child. The treatment will most likely involve ongoing care from a team of healthcare workers. Rehabilitation is the most common type of treatment, and it is done through the following:

• Physical therapy – This is usually started almost immediately in babies that have feeding difficulties. They are used to address the issues with sucking and swallowing. It can also be used for the child’s physical development by teaching them how to sit and stand and improve their fine motor skills.
• Speech therapy – This can assist the child with the issues they have in communication. Speech therapists can teach the child the different methods of communicating, like sign language and also the technology-assisted forms of communication. They can also help with feeding issues at an early age.
• Occupational therapy – This therapy may help the child by providing interventions that can help them develop skills to interact with the world around them. These include fine motor, visual, self-care and sensory skills.

In some cases, surgery may also be recommended in addition to the above therapies to treat a variety of symptoms.The surgery may be done to correct congenital heart defects, crossed eyes, and the bent spinal column. 

What is the life expectancy for cri du chat?

This is variable and depends on various factors. The size and location of the deletion is a major factor in the prognosis. The child will have significant limitations in their physical and mental development, but most children with cri du chat have a normal life expectancy. Prompt diagnosis is also another important factor in the prognosis. This allows for early intervention and therapeutic methods that can help in the child’s success. However, some of the affected children are born with life-threatening health challenges. Of these children, more than half of them will die during their first month of life. This death rate decreases after the first few years of life.

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