Triploidy is a chromosome abnormality that occurs when there is an extra set of chromosomes present in each cell. The signs and symptoms associated with Triploidy vary but may include a variety of birth defects and an unusually small size. Those with the mosaic form, the form in which only some cells in the body have an extra set of chromosomes, may have less severe signs and symptoms. This condition does not run in families and is not associated with maternal or paternal age.