Fluorescence in situ Hybridization (FISH)
*Performed by affiliate laboratory
5mL peripheral blood in sodium heparin
3mL bone marrow in sodium heparin
Fixed cytogenetically prepared cells in sterile centrifuge tube with pellet visible in 3:1, Methanol:Acetic Acid
4°C to 25°C during transit, but specimens may be transported on refrigerated gel packs. Do not allow the gel pack to come in contact with the specimen. Do not freeze. Extreme temperatures should be avoided.
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative
It is recommended that all FISH studies be done in conjunction with routine cytogenetic studies. If the FISH result is normal, a chromosome analysis allows identification of more complex abnormalities.
Williams syndrome is a rare genetic disorder found in approximately 1 in 7,500-20,000 people. A deletion on chromosome 7 is the cause for the disorder. This region includes several genes that most likely contribute to the characteristic features. Usually this disorder is seen as a random event and not inherited.
Elçioglu N et al. (1998). FISH analysis in patients with clinical diagnosis of Williams syndrome. Acta Paediatr. 87(1):48-53.