Cri du chat syndrome

Cri du chat syndrome is a rare genetic disorder caused by a missing section on a particular chromosome, known as Chromosome 5. Sometimes material from another chromosome is missing as well. Around 1 in every 50,000 or so babies is diagnosed with the disorder.

This estimate is coming down. With more advanced and more frequent genetic testing, and many milder cases now being diagnosed, the rate may be as low as 1 in 25,000. Around a third as many girls as boys are affected. Other names for the condition include cat-cry syndrome, 5p minus syndrome and Lejeune’s syndrome.

It is not the result of anything the parents have done or failed to do.

How it affects a child#

Chromosomes carry our inherited characteristics, such as eye colour. In a child with cri du chat syndrome, some of the genes on Chromosome 5 are missing, usually for reasons unknown. The impact can vary from one child to the next, but most will have delayed development and some degree of intellectual disability.

There is no cure, but treatments including speech therapy, physiotherapy and occupational therapy can help a child reach their full potential.

Symptoms#

Cri du chat syndrome is often diagnosed at birth. Symptoms in a newborn baby can include:

• a high-pitched, cat-like cry, or a weak cry
• low birth weight
• a small head
• a rounded face
• a broad, flattened bridge of the nose
• eyes spaced wide apart
• folds of skin over the eyelids
• malformations of the ears
• abnormalities of the palate, such as an unusually narrow and high palate
• a receding, small chin

Health problems#

Children with cri du chat syndrome commonly experience health problems including:

• difficulties with suckling and swallowing
• gastric reflux
• constipation
• a high rate of infections, such as ear and upper respiratory tract infections
• poor muscle tone
• eye problems, such as a squint (strabismus)
• hearing loss

Problems that occur less frequently include deformities of the skeleton, such as curvature of the spine (scoliosis), hernias, and heart and kidney problems.

Causes#

No one knows what causes the deletion of certain genes on Chromosome 5. In most cases the change happens spontaneously, with no family history. The risk of a couple with normal chromosomes having another child with cri du chat is around 1 per cent.

In some cases, one of the parents has abnormalities of Chromosome 5. Genetic counselling for these couples is important, as subsequent children may also have cri du chat syndrome. Medical tests such as amniocentesis, where a sample of amniotic fluid is examined, can determine whether an unborn baby has cri du chat syndrome.

Severity varies#

The severity of the condition can vary widely. Some children are only mildly affected and reach developmental milestones, such as walking and talking, at the usual ages, though they may still need speech therapy.

Other children are profoundly intellectually disabled, unable to walk or talk, and have related health problems and a reduced life span. Most children born with cri du chat syndrome fall between these two extremes, with moderate intellectual disability, varying degrees of speech delay and some health problems, but most learn to walk some time before the age of six.

It is impossible to predict whether a newborn baby with cri du chat syndrome will be mildly, moderately or severely affected. This only becomes clear as the child gets older.

Treatment#

There is no cure for cri du chat syndrome. Treatment aims to stimulate the child and help them reach their full potential, and can include:

• physiotherapy to improve poor muscle tone
• speech therapy, and communication alternatives such as sign language, since speech is usually delayed, often severely
• occupational therapy to teach coping strategies

Support for parents#

Support networks for cri du chat syndrome can offer counselling, information, referral and advocacy, and can connect you with other individuals and families affected by the condition.

Genetic counselling#

If your child has been diagnosed with cri du chat syndrome, or if it runs in your family, it can help to speak to a genetic counsellor. Genetic counsellors are health professionals qualified in both counselling and genetics. As well as providing emotional support, they can help you understand the condition and what causes it, how it is inherited, and what a diagnosis means for your child’s health and for your family.

Genetic counsellors are trained to provide information and support that is sensitive to your family circumstances, culture and beliefs. If cri du chat syndrome runs in your family, a genetic counsellor can explain what genetic testing options are available to you and other family members. You may choose to see a genetic counsellor if you are planning a family, to find out your risk of passing the condition on to your child, or to arrange prenatal tests.

Key points#

• Symptoms in a newborn baby can include malformations of the ears.
• No one knows what causes the deletion of certain genes on Chromosome 5.
• The risk of a couple with normal chromosomes having another child with cri du chat is around 1 per cent.
• Genetic counselling for these couples is important, as subsequent children may also have cri du chat syndrome.

Where to get help#