What are the main symptoms of Cri-du-chat syndrome?
Individuals with Cri-du-chat syndrome are usually small before and at birth and have a small head (microcephaly). Cri-du-chat syndrome causes a set of distinct (dysmorphic) facial features, possibly including a round face, widely-spaced eyes, folds over the inside corner of the eye (epicanthic folds), small chin (micrognathia), ears that are positioned lower on the head than typically seen, and a down-turned mouth. At birth, the most striking feature of Cri-du-chat syndrome is typically a cry that sounds like a cat. Babies with Cri-du-chat syndrome can be born with problems in their heart, kidneys, and brain, although this is uncommon.
Infants with Cri-du-chat syndrome may require respiratory treatment if they are unable to breathe properly. It is common for newborns with Cri-du-chat syndrome to have weak or floppy muscles (hypotonia), and so they may have trouble taking a bottle or breastfeeding.
Children with Cri-du-chat syndrome are expected to remain smaller than their peers, including having a small head (microcephaly). Individuals with Cri-du-chat may develop a long, narrow face, an eye problem known as strabismus (in which the two eyes do not line up properly), abnormal dentition (an abnormal bite), short stature, and early graying of the hair. Other problems with the eyes can also happen, including cataracts (eye clouding) and myopia (only being able to see objects close up, known as nearsightedness). As individuals with Cri-du-chat age, their muscles may become tight and stiff (hypertonia). There are other less common health problems that have only been seen in a few people with Cri-du-chat syndrome, including seizures and elastic (stretchy) skin.
Individuals and families who have questions about Cri-du-chat syndrome, including the symptoms typically seen and the natural history of the disorder, may benefit from consultation with a medical geneticist and genetic counseling. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website . Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
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Are there earlier onset, later onset, or variant forms of Cri-du-chat syndrome?
Not all individuals with Cri-du-chat syndrome are affected in the same way, and not all affected individuals develop all of the symptoms that may be part of Cri-du-chat syndrome. Some of this variability between individuals with Cri-du-chat syndrome may be caused by differences in the size of the specific deletion (missing piece) of chromosome 5. Individuals with larger deletions have more genes missing and may be more severely affected than individuals with smaller deletions and therefore fewer genes missing. Some, but not all, of the variation between individuals affected with Cri-du-chat syndrome may be explained by this.
What health problems should I look for in Cri-du-chat syndrome?
Some babies with Cri-du-chat syndrome develop breathing problems after birth and require respiratory treatment. Signs of breathing problems may include difficulty or irregular breathing and/or the skin turning blue. Because infants with Cri-du-chat syndrome tend to have weak or floppy muscles (known as hypotonia), they may have difficulty taking a bottle or breastfeeding. Some babies with Cri-du-chat syndrome are born with problems in their heart, kidneys, and brain. In the first year of life, many babies with Cri-du-chat syndrome will develop infections in their intestines and/or lungs. Individuals with Cri-du-chat syndrome may experience difficulty eating and/or reflux in childhood. Problems with the eyes can also occur, including cataracts (eye clouding) and myopia (only being able to see objects close to the face).
If infants or children with Cri-du-chat syndrome require surgery, careful monitoring related to being put to sleep (anesthesia) is indicated. Some individuals with Cri-du-chat syndrome have changes in the shape of their airway which makes giving anesthesia more difficult.
Individuals with Cri-du-chat syndrome should receive routine primary care. There are publications in the medical literature regarding health supervision recommendations for individuals with Cri-du-chat syndrome, and individuals and families with Cri-du-chat syndrome may benefit from consultations with a medical geneticist and genetic counseling. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website . Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Are there any other conditions that look a lot like Cri-du-chat syndrome?
Some of the features typically seen in individuals with Cri-du-chat syndrome are commonly found in other conditions as well (not specific to Cri-du-chat syndrome). However, the characteristic "cat-like" cry of the newborn is very specific to Cri-du-chat syndrome. Taken together, the characteristics typically found in individuals with Cri-du-chat syndrome leads to this syndrome being specifically suspected by a medical geneticist or other physician familiar with Cri-du-chat syndrome. Once suspected, it can then be confirmed with genetic testing.
One other genetic syndrome, also the result of a chromosome deletion (missing a piece of a chromosome, but a different one than Cri-du-chat), called Wolf-Hirschhorn syndrome, has some clinical features in common with Cri-du-chat. Cri-du-chat syndrome and Wolf-Hirschhorn syndrome can be easily differentiated by genetic testing.
If you are interested in learning more about the availability of genetic services in your area, you can ask your primary care physician for a referral. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website . Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Is there one or two characteristic "odd" or "unusual" symptom or clinical feature of Cri-du-chat syndrome?
Cri-du-chat, in French, means "cry of the cat". The "cat-cry" sound typical in newborns with Cri-du-chat syndrome is very characteristic of this condition and may be an important clue in diagnosis.
Do all people who have a deletion of chromosome 5p have Cri-du-chat syndrome?
There is a typical area on chromosome 5p, which, when deleted, is expected to result in an individual having features of Cri-du-chat syndrome. However, not all individuals with Cri-du-chat syndrome have the exact same piece of chromosome 5 missing. Scientists are learning about the role of some of the genes in this region on chromosome 5 and, depending on whether those specific genes are included or not included in the deletion in a given person, are sometimes able to make predictions about which feature(s) of Cri-du-chat syndrome may be found in that individual (this is called genotype-phenotype correlation).
In general, the larger a given individual's deletion is, the more symptoms of Cri-du-chat syndrome that person may be predicted to have. Larger deletions may generally be predicted to lead to more "severity" of symptoms and health problems. However, even if two people have the same size deletion as each other, they may have different symptoms. This is called variable expression.