Impact of genotype-first diagnosis: the detection of microdeletion and microduplication syndromes with cancer predisposition by aCGH.

Background: The use of microarray-based comparative genomic hybridization has allowed the genetic diagnosis of some conditions before their full clinical presentation. This "genotype-first" diagnosis has the most clinical implications for genomic alterations that confer an elevated risk of cancer. In these cases, diagnosis before the manifestation of the patient's full phenotype dramatically impacts genetic counseling, clinical management, and eventual prognosis and survivability.

Primer on medical genomics. Part XI: Visualizing human chromosomes.

In the past century, various methods to visualize human chromosomes were discovered. Chromosome analyses provide an overall view of the human genome that cannot be achieved with any other approach. The methods to visualize chromosomes include various techniques to produce bands along chromosomes, specialized procedures for specific disorders, and fluorescent-labeled DNA for targeted loci.