Causal Factors of Cri Du Chat Syndrome

Unbalanced Translocationcan just be lost or it can get attached to a different
When a part of a chromosome breaks and attacheschromosome.
to a different chromosome, the process is referredInversion
to as translocation. If there is no loss or gain ofA chromosome can break at more than a single point
material during this process, it is called balancedsometimes. When it does at two points in the arm,
translocation which does not affect the individual.this broken portion can flip, invert and reattach to
However, when there is a loss or gain, it refers tothe chromosome. Owing to the reversal in genetic
unbalanced translocation and results in a geneticcode in this particular section, there are chances for
disorder. In case of the occurrence of a balancedthe occurrence of the syndrome.
translocation in a parent, there are 10% chances forDuplication/ Partial Trisomy
unbalanced translocation to occur in the new-bornA portion of the short arm in the chromosome
child. But there are also cases, wherein the childnumber five can get duplicated at times and when
experiences a de novo or spontaneous unbalancedthis includes the critical region of the chromosome, it
translocation at times.can result in a disorder. The duplicated portion will
attach within the chromosome or at its ends and the
In some rare cases, there are chances where thecode will be misread.
chromosome just loses a part or piece from each ofMosaicism
its ends and these ends can unite to form a ring. InIn rare cases, the deleted chromosome can be
the child who possesses cri du chat syndrome, thispresent in some cells of our body rather than in all.
ring can lead to further problems based on theThis content may vary like 20% or 75%. Based on
amount and length of genetic material lost. Andthe occurrence of the deletion in the types of body
especially, when the loss is from the chromosome'scells and the percentage of occurrence, the child can
long arm, it is very likely to result in the occurrenceeither be mildly or severely affected. This case
of the syndrome.presents a difficult diagnosis, since the portion of
Interstitial Deletionblood or tissue sample collected must contain the
In some other cases, a portion from inside of thecells with deletion or it would result in a wrong
short arm of the chromosome can get deleted or cutdiagnosis.
and the broken ends can rejoin. The cut off portion