FISHing for answers: the use of molecular cytogenetic techniques in adolescent medicine practice.

Chromosomal abnormalities are common causes of a variety of diseases, cancers, and malformation syndromes. Identification of chromosomal aberrations is important for counseling families about prognosis and reproductive risks with future pregnancies. However, limited resolution leads to the inability to detect small deletions, small insertions or duplications, and complex chromosomal rearrangements. Fluorescence-based assays, which have become possible because of sophisticated cloning technologies and improved sensitivity of antibody conjugates, enable the detection of subtle chromosomal changes beyond the resolution of classic cytogenetics. Such techniques have greatly expanded the diagnostic armamentarium available in the investigation of adolescents with mental retardation, malformations and many other disorders.