Genetic Reasons for Cri Du Chat
Actual photo of Chromosome 5 and image showing the deleted region
Cri Du Chat is caused by a partial deletion of part of the short arm region in Chromosome 5, also known as 5p monosomy. This is caused 90% of the time by random deletion. The other 10% is caused by an unequal seperation of parental balanced translocation, when the 5p monosomy is joined by a trisomic part of the gene. People affected by this see more severe cases of Cri Du Chat than those with random deletion.
The partial deletion usually accounts for 10-20% of genetic material missing on the short arm. Missing parts of Chronosome 5's 15.2 region (called the Cri Du Chat critical region) contribute to the physical features of someone with the disorder while region 15.3 contributes to the Cat's Cry symptom. Other regions of Chromosome 5 are being studied to determine what further contributes to the disorder.
The cause of Cri Du Chat has been reported to be mostly paternal in the random deletion scenario. Causes can be traced back to the development of the sperm or egg. Less common cases occur when the parent gives a rearranged form of Chromosome 5 to his or her offspring.
The partial deletion usually accounts for 10-20% of genetic material missing on the short arm. Missing parts of Chronosome 5's 15.2 region (called the Cri Du Chat critical region) contribute to the physical features of someone with the disorder while region 15.3 contributes to the Cat's Cry symptom. Other regions of Chromosome 5 are being studied to determine what further contributes to the disorder.
The cause of Cri Du Chat has been reported to be mostly paternal in the random deletion scenario. Causes can be traced back to the development of the sperm or egg. Less common cases occur when the parent gives a rearranged form of Chromosome 5 to his or her offspring.