Chromosome Analysis, High Resolution (Blood)

High resolution chromosome analysis requires the use of elongation methods to obtain a high percentage of prophase and prometaphase spreads. The chromosomes are less condensed than in routine metaphase analysis, and the number of identifiable bands is expanded, allowing a more sensitive analysis of the karyotype. This type of study is required for the detection of subtle chromosome rearrangements, and it is considered an important component in the diagnosis of microdeletion syndromes such as Prader-Willi syndrome, Angelman syndrome, Smith-Magenis syndrome, and Miller-Dieker syndrome. For high resolution chromosome analysis a minimum of 20 cells are counted to determine the modal number and a minimum of 5 cells are analyzed for chromosomal abnormalities Because special culture conditions are required, high resolution studies must be specifically requested.