Test Details: FISH helps in aneuploidy detection for autosomes (chromosomes 13, 18 and 21) and sex chromosomes which accounts for greater than 90% of chromosomal aberrations. Autosomal monosomies are usually not compatible with life. Autosomal trisomy of chromosomes 13 and 21 are most common trisomy detected in live-births. Trisomy 21 is associated with Down Syndrome and is the single most common known cause of mental retardation. Trisomy-13 is associated with Patau Syndrome. Sex chromosomal aberrations such as Klinefelter Syndrome (47,XXY) and Turner Syndrome (45,X) can also be detected using FISH.