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. Trisomy 18 is associated with Edward Syndrome. Sex chromosomal aberrations such as Klinefelter Syndrome (47,XXY) and Turner Syndrome (45,X) can also be detected using FISH. Prenatal Diagnosis of cord blood cells is an effective and safe prenatal screening method for trisomy 21, 18 and 13 as well as sex chromosomal abnormalities in the average-risk or general population.