Abstract
Chromosomal abnormalities are a frequent cause of pediatric disorders, including rnental retardation, malformation tion syndromes and neoplasia. Many of these chromosomal abnormalities can be detected with a standard kasyotype, although some alterations are too small to be visualized by conventional light microscopic analysis. Fluorescence in situ hybridization has greatly enhanced the detection of subtle chromosome abnormalities, and has become a routine adjunct to conventional cytogenetics. We describe different fluorescence in situ hybridization techniques and give examples of how these techniques are applied to disorders that are frequently encountered in the pediatric population. (The J Histotechnol 27:259, 2004)