What is cri-du-chat syndrome?
Cri-du-chat syndrome is a genetic condition. Also called cat’s cry or 5P- (5P minus) syndrome, it’s a deletion on the short arm of chromosome 5. It’s a rare condition, occurring in only about 1 in 20,000 to 1 in 50,000 newborns, according to the Genetics Home Reference. But it’s one of the more common syndromes caused by chromosomal deletion.
“Cri-du-chat” means “cry of the cat” in French. Infants with the syndrome produce a high-pitched cry that sounds like a cat. The larynx develops abnormally due to the chromosome deletion, which affects the sound of the child’s cry. The syndrome is more noticeable as the child ages, but becomes difficult to diagnose past age 2.
Cri-du-chat also carries many disabilities and abnormalities. A small percentage of infants with cri-du-chat syndrome are born with serious organ defects (especially heart or kidney defects) or other life-threatening complications that can result in death. Most fatal complications occur before the child’s first birthday.
Children with cri-du-chat who reach age 1 generally will have a normal life expectancy. But the child will most likely have lifelong physical or developmental complications. These complications will depend on the severity of the syndrome.
About half of children with cri-du-chat syndrome learn enough words to communicate, and most grow up to be happy, friendly, and sociable.
The exact reason for the chromosome 5 deletion is unknown. In most cases, the chromosome break happens while the parent’s sperm or egg cell is still developing. This means the child develops the syndrome when fertilization occurs.
According to the Orphanet Journal of Rare Diseases, the chromosome deletion comes from the father’s sperm in about 80 percent of cases. The syndrome is not typically inherited, though. Only about 10 percent of cases come from a parent who has a deleted segment, according to the National Human Genome Research Institute. About 90 percent are presumed to be random mutations.
It’s possible that you may carry a type of defect called a balanced translocation. This is a defect in the chromosome that does not result in the loss of genetic material. However, if you pass the defective chromosome to your child, it may become unbalanced. This results in the loss of genetic material and can cause cri-du-chat syndrome.
Your unborn child has a slightly increased risk of being born with the condition if you have a family history of cri-du-chat syndrome.
The severity of your child’s symptoms depends on how much genetic information is missing from chromosome 5. Some symptoms are severe while others are so minor they may go undiagnosed. The cat-like cry, which is the most common symptom, becomes less noticeable over time.
Children born with cri-du-chat are often small at birth. They may also experience respiratory difficulties. Besides the namesake cat cry, other physical features include:
- small chin
- unusually round face
- small bridge of the nose
- folds of skin over the eyes
- abnormally wide-set eyes (ocular or orbital hypertelorism)
- abnormally shaped or low-set ears
- a small jaw (micrognathia)
- partial webbing of the fingers or toes
- single line on the palm of the hand
- an inguinal hernia (a protrusion of organs through a weak area or tear in the abdominal wall)
Internal problems are common in children with the condition. Examples include:
- skeletal problems like scoliosis (abnormal curvature of the spine)
- heart or other organ defects
- poor muscle tone (during infancy and childhood)
- hearing and vision difficulties
As they grow, they often experience trouble talking, walking, and feeding, and can have behavioral problems, such as hyperactivity or aggression.
Children also may suffer from severe intellectual disabilities, but should have a normal life expectancy if they don’t experience defects with major organs or other critical medical conditions.
The condition is usually diagnosed at birth, based on physical abnormalities and other signs like the typical cry. Your doctor may perform an X-ray on your child’s head to detect abnormalities in the base of the skull.
A chromosome test that uses a special technique called a FISH analysis helps detect small deletions. If you have a family history of cri-du-chat, your doctor may suggest a chromosome analysis or genetic testing while your child is still in the womb. Your doctor can either test a small sample of tissue from outside the sac where your child develops (known as chorionic villus sampling) or test a sample of amniotic fluid.
There is no specific treatment for cri-du-chat syndrome. You can help manage symptoms with physical therapy, language and motor skill therapy, and educational intervention.
There is no known way to prevent cri-du-chat syndrome. Even if you don’t display symptoms, you may be a carrier if you have a family history of the syndrome. If you do, you should consider getting a genetic test.
Cri-du-chat syndrome is very rare, so it’s unlikely to have more than one child with the condition.