|New Diagnostic Procedures|
Cri Du Chat Syndrome (CdCS) can be detected before birth if the mother undergoes amniocentesis or chorion villus sampling. In amniocenesis, cells from the fluid surrounding the fetus are collected and analyzed for genetic defects, while in chorionic villus sampling, these cells are collected from the sac that holds both the fetus and the fluid (www.chclibrary.org).
(Picture taken from http://www.nlm.nih.gov/medlineplus/ency/imagepages/1062.htm)
Once the baby is born, the syndrome is strongly suspected if the characteristic cat-like cry is heard. (www.healthatoz.com) A sound clip of the cat-like cry...click here and click here The newborn may also have physical characteristics that would cause doctors to suspect CdCS. Some of these physical characteristics include:
When features such as these are witnessed, karyotyping should be performed. “Karyotyping involves staining chromosomes and examining them under a microscope.” (www.healthatoz.com) One should be able to see whether or not there are deletions or translocations in chromosome 5 from this analysis, yet if this is not observed, one can also perform cytogenetic and molecular-cytogenetic (the study of the structure of chromosome material) analyses. These cytogenetic analyses include previewing the G-Banded chromosomes as well as molecular cytogenetics such as FISH (fluorescent in situ hybridization) and CGH (comparative genomic hybridization). (www.answers.com) An explanation of the FISH technique can be read here. The nature of the chromosome defect, such as ones in chromosome 5 causing CdCS, can be detected by using techniques such as these. Immediately following these first few discoveries, karyotyping should be performed. “Karyotyping involves staining chromosomes and examining them under a microscope.” (www.healthatoz.com)
Upon performing a combination of FISH and CGH, it was confirmed that the characteristic cat-like cry was due to the deletion at 5p15.3. (orphnet paper)