The Cri du Chat

Cri du chat syndrome, also known as 5p minus (5p-) syndrome or cat cry syndrome, is a rare chromosomal disease caused by the deletion of genetic material on chromosome 5's small arm (the p arm) (Chon & Russel 144). It is a genetic disease that affects about one in every 20,000 to 50,000 newborns. Infants with this syndrome have a high-pitched scream that sounds like a kitten. This cry sound resembles that of a cat and is usually produced due to the abnormal development of the larynx of an infant as a result of the chromosome deletion. Cri du chat syndrome is marked by delayed development, intellectual disability, weak muscle tone in infancy, distinctive facial features, low birth weight, and small head size. There is a significant female predominance that is observed in the newborns that are affected with this syndrome. A significant female predominance has been observed in the infants who have been affected with a male to female ratio of 0.72:1.

The exact cause for the chromosome 5 deletion is still unknown, but in most cases, the chromosome break occurs while the parent’s egg or sperm cell is still developing. This means that a child develops the syndrome when fertilization occurs. Mental retardation of those who have Cri du Chat is linked to the loss of a particular gene CTNND2 which is responsible for providing instructions for making a protein called delta-catenin (Chon & Russel 174). The delta-catenin protein is responsible for intracellular attachment of neurons and cellular movement. When deleted, the affected individual will have severe mental retardation and poor motor skills since their cell to cell communication within the nervous system is not efficient as those with the gene. The individuals that have Cri du Chat syndrome but still have the CTNND2 gene intact will experience mental retardation that is mild or even in some instances will demonstrate normal intelligence. The severity of signs and symptoms of Cri du Chat syndrome vary from case to case as it depends on how much genetic information is missing from the chromosome 5. At times, the symptoms are so minor that there are chances that they may go undiagnosed which makes it difficult to determine the actual frequency of the disorder in the general population. The most common sign of Cri du Chat syndrome is cat like a cry in infancy though many children lose it by the time they are two years old. The signs of Cri du Chat include low birth weight and poor physical growth, microcephaly, wide-apart eyes, eyes looking in different directions, skin folds covering the inner corner of the eyes, small jaw, low-set ears, short fingers, and lines that run across the palms (Coleman 254). Development signs in children with Cri du Chat syndrome include motor delay especially in walking and profound intellectual disability. Behavior signs of Cri du Chat syndrome include sleeplessness, hyperactivity, aggression, tantrums, and repetitive movements.

Symptoms of Cri du Chat include feeding problems because of difficulty in swallowing and sucking, lots of drooling, low muscle tone, constipation, gastroesophageal reflux disease, hearing and vision difficulties, and abnormalities of the palate like an unusually narrow and high palate. Some of the children might even be at risk of getting aspiration which can result in pneumonia. Some of the children with Cri du Chat syndrome are born with serious organ defects and other life threatening problems which can end up to be fatal. The most fatal cases usually happen before the child gets to one year. Generally, most of the children who have this syndrome have a normal life expectancy, but they will still experience the physical and developmental problems which will depend on the severity of the disorder (Coleman 301). Many of the cases of Cri du Chat syndrome are not inherited. The deletion is usually a spontaneous event that occurs during the formation of reproductive cells or in the early development fetus. Those affected with this syndrome usually do not have a history of this syndrome in their family. Of all the people who have Cri du Chat syndrome, around ten percent inherit the chromosome with a segment that is deleted from an unaffected parent. In such cases, the parent is a carrier of a chromosomal rearrangement which is known as balanced translocation whereby no genetic material is gained or lost. The balanced translocations do not have any adverse health effects because they might become unbalanced as they are passed to the next generation. The children who inherit the unbalanced translocation can have a chromosomal rearrangement with extra or missing genetic material. The individuals with Cri du Chat syndrome who inherit the unbalanced translocation are usually lacking the genetic material from the short arm of chromosome 5 which is responsible for the intellectual disability and health problems characteristics that are common with this disorder.

The onset of Cri du Chat is usually from birth as it can be easily detected because of the catlike cry and the dysmorphic features (Lindsey 405). This syndrome is found in people of all races and ethnic groups; there is no race where it is more prevalent than the others. The diagnosis of Cri du Chat syndrome is usually done at birth based on the physical abnormalities and displayed symptoms by the physician. Chromosomal studies are then conducted that reveal the deletion on the short arm of the chromosome. The doctor may also have to perform an X-ray of the child’s head to check for abnormalities that could be on the base of the skull and to determine the extent of the disorder. To be able to have a complete diagnosis a particular chromosome, tests must be carried out. The particular test that is conducted is known as the fluorescence in situ hybridization (FISH) which confirms the diagnosis of the syndrome. If a family has a history of Cri-du Chat syndrome, the doctor may suggest that a chromosome analysis or genetic testing to be conducted while the child is still in the womb. With the scientific techniques, determining chromosomal abnormalities are becoming more and more refined that they have made a prenatal diagnosis of Cri du Chat syndrome possible. The doctor might choose to test a small sample of tissue from outside the sac where the child is developing or test a sample of amniotic fluid.

There are no specific treatments that are available for Cri du Chat, but early intervention is highly recommended so that the child can reach their highest potential. The treatment of this syndrome is usually directed toward the specific symptoms that are evident in each individual and may also require the coordinated efforts of a team of specialist. The specialists could range from pediatricians, cardiologists, neurologists, orthopedists, speech pathologists, dentist, physical, and occupational therapists (Lindsey 670). The treatments offered include physiotherapy, occupational therapy, speech therapy, special remedial education, and surgery which can be used to correct congenital heart defects, scoliosis, clubfoot, strabismus, cleft palate and cleft lip. Physiotherapy is also seen to help the child’s physical development like helping them to sit, stand and improve their fine motor skills. Occupational therapy works in conjunction with physiotherapy to improve the children’s fine motor movement and activities of daily living.

Most of the deaths of Cri du Chat syndrome occur before and during the first year of the birth of a child which amounts to about 90%. The 10% who do survive the first few years have very lower mortality rates (Chon and Russel 559). A small percentage of the children with the syndrome are born with serious organ defects and other medical problems that are life-threatening, and in such cases, this child usually has a worse prognosis. Early diagnosis and continuous treatment might reduce the burden that comes with the disorder. For an individual to have a favorable outcome, they will have to go through extraordinary treatment measures, support and rehabilitation, which may, in the end, lead to a better social adaptability, communication skills, and greater independence. The recent improvements in management and rehabilitation programs have promoted increased psychomotor development, improved autonomy, and better social adaptation. Until recently, there was little that was known about the cognitive function of patients with Cri du Chat syndrome. New studies have shown that many children can develop some motor and language skills. These kids can also achieve the developmental and social skills that are familiar with the kids of the age bracket of five and six, but their linguistic abilities are seldom as advanced. The children who are old and home-reared are usually ambulatory and are able to communicate verbally or even through sign language, and independent in self-care skills.

Conclusion

The Cri du Chat syndrome is a rare condition that can cause severe developmental and intellectual disability. Early diagnosis of this syndrome is essential to enable proper counseling of parents and treatment for those who are diagnosed with it. The diagnosis of Cri du Chat can at times be challenging after the age of two or when the clinical findings are not distinctive. While this syndrome is a genetic condition, many of the cases are not as a result of inheritance. Children and adults who have this condition need all the support that they can get so as to relieve the burden that syndrome has on them as well as their families. More awareness should continue to be raised so that people can understand it more and also know that it can be found in any race, ethnic, and religious group. There is no known way that can be used to prevent Cri du Chat syndrome. Even when one does not have symptoms they might still be carriers if there is a history of the syndrome in their family and as such, they should consider having a genetic test. With the right treatment, a child is assured of reaching their full potential and become independent.

Work Cited

Cohn, Jesse Russell & Ronald. Cri Du Chat. 140-157: Book on Demand, 2012.

Coleman, Mary. Chromosome Disorders: Advances in Research and Treatment: 2011 Edition: ScholarlyBrief. 174-344: ScholarlyEditions, 2012.

Lindsey, Mary P. Dictionary of Mental Handicap. 147-984: Routledge, 2012.