Cri du chat syndrome

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C syndrome is a rare genetic disorder caused by a genetic mutation where a portion of chromosome five is deleted or missing.
The name is a French term that refers to the characteristic high pitched cry of the affected babies which sounds like the cry of a cat or le du.
All right, let's break this down. Our DNA is packaged into 46 chromosomes which contains the genes that are pretty much instructions for making proteins.
These proteins control everything from growth and development to the day to day functioning of the cells. Each of the 26 chromosomes is actually made up of a pair of chromosomes and you get one from each parent.
So 23 pairs. Now these chromosomes have two rod shaped arms, one short and one long hooked together in the middle by a centromere.
These two short arms are referred to as P arms from the French term petit, that means small in cretus Shah syndrome, a part of one of the short arms of chromosome five is missing.
So, Credo Shah syndrome is also known as five P deletion syndrome or five P minus. OK.
So 80 to 85% of the cases of Cri Du Shah syndrome are the result of de novo deletion, which means they occur on their own without being inherited.
However, in 10% of the cases, the deletion is inherited from a parent who has a balanced translocation translocation means that a part of one chromosome switches places with a part from another chromosome and it's balanced.
So there's no genetic material gained or lost. So the person doesn't experience any adverse effect.
As an example, let's say this woman has 23 pairs of normal chromosomes and here is her boyfriend. And in his karyotype, we can see that a part of chromosome five has switched places with a part of chromosome 11, but he remains normal because no genetic material is gained or lost.
But if these two have a baby, the baby will randomly inherit two copies of each chromosome, one from mom and one from dad.
Now, since both mom and dad have two copies of each chromosome, if the dad passes on the translocated chromosome five, but the normal chromosome 11, the translocated information from chromosome five will be lost.
So in this case, the balanced translocation in the father will become unbalanced translocation in the child because some genetic material from chromosome five is lost and this baby will have Cri Du Sha syndrome.
All right. Now, symptoms of Cri Du Sha syndrome vary and depend upon the amount of missing genetic material.
The most specific feature is obviously the cat like cry. And it's due to structural abnormalities of the larynx.
Surprisingly, someone can have Creed Shaw syndrome without having this characteristic meowing. Also, they usually have characteristic facies with a small round face with full cheeks, hypertelorism or increased distance between the eyes, prominent supraorbital arches, which are the bony ridges above the orbits and epicanthal folds or skin folds of the upper eyelids that cover the inner angles of the eyes.
In addition, the nose is usually flat with a wide nasal bridge. The ears are low set, there's dropped jaw due to increased facial laxity and dental malocclusion or misalignment of the teeth.
Besides abnormalities in the head and neck, it causes congenital heart defects such as ventricular septal defects. There's also neurological problems including moderate to severe intellectual disability and slower motor development leading to delayed walking and clumsiness.
Other common characteristics of babies with Cretu Sha syndrome include failure to thrive and hypotonia or weak muscle tone, which may become hypertonia later in life.
These babies tend to have chronic medical problems including feeding problems because they have difficulty swallowing, constipation and recurrent infections like otitis media, respiratory infections and urinary tract infections.
Now, the diagnosis of Cri Du Sha Syndrome can be suspected by the clinical features, especially the high pitched cry diagnosis can be confirmed with karyotyping, which visualizes each chromosome and can be done with a blood test if there's a high clinical suspicion.
But the karyotype is negative fluorescence in situ hybridization or fish can be used. This involves a fluorescently labeled probe made of DNA that's complementary to the five P region.
The probes can base pair to both chromosome fives. So you would expect two bright spots are to be seen in the microscope when the cell is viewed under fluorescent light.
If a five P deletion is present though, then one of those regions is missing. So you'll only see a single bright spot now, because creed Sha syndrome is caused by a genetic deletion.
There's no known cure. So management focuses on maximizing the development of the affected babies and treating life threatening conditions like congenital heart defects.
All right. It's a quick recap Criteo Shaw syndrome or five P deletion syndrome is a rare genetic condition where part of the short arm of chromosome five is deleted.
Cretu Shaw syndrome is characterized by the presence of a catlike cry but also facial abnormalities and congenital heart defects.
Additional findings include failure to thrive hypotonia, neurodevelopmental delay and others diagnosis is based on karyotyping to find the chromosomal abnormalities.
And treatment is based on treating life threatening conditions after birth.