An Overview of Cri du Chat Syndrome

Cri du Chat Syndrome (French for "cat cry") is a rare chromosomal disorder caused by missing or deleted portions of chromosome 5. Infants who are born with the syndrome often have a high-pitched cry that sounds like a cat, hence the condition's name. Since the condition occurs due to missing portions of the short arm (p) of chromosome 5, Cri du Chat is also known as 5p- (5p minus) syndrome.

The life expectancy of a person with Cri du Chat syndrome is generally good. Many children with Cri du Chat syndrome live well into middle age and beyond.

In this article, you'll learn what the Cri du Chat syndrome is and what it is like to live with Cri du Chat syndrome. You'll find out what symptoms it causes and how it's diagnosed and treated, and you'll know what to expect for a child with Cri du Chat syndrome.

Symptoms of Cri du Chat Syndrome

The key physical characteristics and symptoms of Cri du Chat syndrome are caused by missing or deleted genes in the small arm (p) of chromosome 5. Researchers suspect that the specific set of symptoms associated with Cri du Chat, and the severity of those symptoms, is linked to the size and location of the deleted or missing portion of the chromosome.

Symptoms in Babies

Like other chromosomal disorders, the symptoms and severity of the condition vary from person to person. However, there are a few key manifestations of the condition that are noticeable from birth. These hallmark features include:

• Low birth weight
• Poor sucking reflex
• Slow growth or failure to thrive
• A high-pitched, mewling cry that sounds like a cat
• Low muscle tone

While they may not have all of the features, many newborns with Cri du Chat have distinct physical characteristics, including:

• A small head (microcephaly) and jaw
• An abnormally round face
• Malocclusion (misalignment) of the teeth
• Wide-set, downwardly slanted eyes
• Extra skin folds around the eyes
• Low-set ears
• "Webbing" of fingers and toes (syndactyly)
• Cleft lip or cleft palate

Symptoms During Childhood

As children with the condition grow up, they may begin to show and experience a spectrum of symptoms related to Cri du Chat, as well as other disorders commonly found in people diagnosed with the condition, including:

• Motor, cognitive, and speech delays
• Moderate to severe intellectual disability
• Psychomotor disability
• Seizures
• Autism-like behaviors, such as hand flapping, rocking, and noise sensitivity
• Scoliosis
• Congenital heart defects (around 15–20 percent of patients)
• Hernias
• Behavioral issues such as tantrums and poor attention/impulse control
• Walking with a slow, guarded gait or the need for mobility aids, including wheelchairs
• Self-destructive behaviors like head banging and skin picking
• Recurrent infections (particularly respiratory, ear, and gastrointestinal)
• Nearsightedness
• Constipation
• Kidney or urinary abnormalities
• Premature graying of hair
• Trouble sleeping
• Toilet training issues

Causes of Cri du Chat Syndrome

Cri du Chat syndrome was first described in 1963 by a French pediatrician named Jérôme Lejeune. Lejeune is most well-known for discovering the genetic basis of trisomy 21 (Down syndrome).

While Cri du Chat is related to genes, it's not necessarily an inherited condition. Most cases occur de novo (or spontaneously) during embryonic development.

Researchers aren't sure why these deletions happen. The parents of a baby born with Cri du Chat because of a spontaneous deletion will have normal chromosomes. Therefore, if they have another baby in the future, it's unlikely that another child will also be born with the condition.

In some cases, the condition occurs because genes are translocated from one chromosome to another. This causes genetic material to be rearranged. Translocations between chromosomes can occur spontaneously or be passed down from a parent who is a carrier of an affected gene.

Researchers suspect that people with Cri du Chat who have severe intellectual disability may have deletions in a specific gene, CTNND2. More research is needed on the potential connection between the condition's symptoms and specific genes. Understanding why the deletions in the gene happen will be an important part of directing diagnosis and treatment to improve the lives of people with Cri du Chat.

Diagnosis of Cri du Chat Syndrome

Most cases of Cri du Chat can be diagnosed at birth as part of a thorough newborn evaluation. The key physical features of the condition, particularly microcephaly, are readily identifiable in newborns. Other associated symptoms, such as the baby's "cat cry," low muscle tone, and poor sucking reflex, are also apparent soon after birth.

A few different types of genetic testing, including karyotyping, fluorescence in situ hybridization (FISH), and chromosome microarray analysis, can be used to look for deletions in chromosome 5 which are diagnostic of Cri du Chat.

A doctor may also order more highly specialized tests to determine if the deletions were spontaneous or from a parent's affected gene. If the latter is the case, there are tests that can identify which parent has the translocated gene.

The increasing availability of more specialized genetic testing techniques has allowed some cases of Cri du Chat to be diagnosed prenatally.

Treatment for Cri du Chat Syndrome

The severity of Cri du Chat exists on a spectrum. The experience of having, being diagnosed with, and treating the condition and its symptoms will be unique to each person who has it.

Families who have children with Cri du Chat often enlist the help of many different types of healthcare providers, including allied health professionals, social workers, and education specialists. After the birth of a child with Cri du Chat, parents are usually referred for genetic counseling.

As Cri du Chat is often diagnosed at birth or shortly thereafter, families can begin building a support team right away. Early intervention helps families develop strategies for managing both the physical and emotional differences children with Cri du Chat face compared to their peers.

The majority of children diagnosed with Cri du Chat begin some form of therapy before their first birthday. This often includes a combination of physical, occupational, and speech therapy. If an associated health condition, such as a congenital heart defect, is present, the patient will need more specialized medical services in addition to routine care.

Parents may need to seek out community and academic resources to help children with Cri du Chat adjust to school. Special education programs are one option, depending on the type and extent of the child's learning and/or physical disability, as well as taking into consideration their social and behavioral needs. Some families choose to homeschool children with Cri du Chat or enroll them in specially designed schools or programs.

Prognosis for Cri du Chat Syndrome

The life expectancy of patients with Cri du Chat is usually not affected by the condition. Symptom-related deaths tend to occur within the first year of life. In many cases, however, children with Cri du Chat syndrome have lived to be over 50 years of age.

However, complications from the features of Cri du Chat syndrome can occur. Poor muscle tone and sucking can lead to the development of aspiration pneumonia in some infants. Patients with Cri du Chat syndrome are also more prone to ear infections and hearing loss.

However, people who have Cri du Chat are not always able to live independently. Many adults with the condition will need supportive health, social, case management, and vocational services.

Alternative and complementary therapies can also be helpful for patients with Cri du Chat, especially during childhood and adolescence. Play therapy, aromatherapy, music therapy, and therapy involving animals have all been shown to benefit children with Cri du Chat.

For children who have more severe disabilities, require feeding tubes (parenteral nutrition), and those who engage in serious self-injurious behavior may require additional care. Home health nurses, community living, or nursing facilities are also options for families who need assistance with helping their child live a full, safe, happy, and healthy life.

Summary

Cri du Chat syndrome is a rare genetic disorder caused by a genetic mutation on chromosome 5. Its symptoms exist on a spectrum and can include severe intellectual and physical disabilities, delays in speech or motor functions, and behavioral problems, or other medical conditions, such as congenital heart defects or scoliosis.

Complications related to this condition, or those that commonly co-occur with it, can cause serious health problems. Treatment is specialized to the needs of each child. Most people with Cri du Chat live well into middle age and beyond.

Talk to a healthcare provider about genetic testing if you are concerned about Cri du Chat syndrome. Health and social services as well as genetic counseling are available to assist families.