Multi-Telomere FISH

The standard investigation for suspected chromosomal rearrangements in patients is cytogenetic analysis at a 400–550 band resolution, yet this cannot routinely detect rearrangements smaller than 5 Megabases (Mb), and much larger abnormalities escape notice if they occur in regions where the banding pattern is not distinctive. In the future, this problem will largely be solved by the use of high resolution micro-arrays that will allow the entire genome to be investigated for submicroscopic chromosomal rearrangements. However, until this technology becomes routine, the only way of achieving increased reliability and resolution is to focus on specific chromosomal regions such as the ends of chromosomes (telomeres).