<unk>  types are categorized based on the number of extra chromosomes in each set, noted as a diploid (2n) with an extra chromosome of various numbers. For example, a<unk>  with three chromosomes is called a trisomy, a<unk>  with four chromosomes is called tetrasomy, etc.: Number of chromosomes Name Description Examples 3 trisomy Three copies of a chromosome, 2n + 1 Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), or Patau syndrome (Trisomy 13) 4 tetrasomy Four copies of a chromosome, 2n + 2 Tetrasomy 9p, Tetrasomy 18p 5 pentasomy Five copies of a chromosome, 2n + 3 Pentasomy X (XXXXX or 49, XXXXX) 6 hexasomy Six copies of a chromosome, 2n + 4 Mosaic Hexasomy 21 or Partial Hexasomy 15 7 heptasomy Seven copies of a chromosome, 2n + 5 Heptasomy 21 in acute myeloid leukemia 8 octosomy Eight copies of a chromosome, 2n + 6 Octosomy in sturgeon fish (Acipenser baerii, A. persicus, A. sinensis, and A. transmontanus) 9 nanosomy Nine copies of a chromosome, 2n + 7 Nanosomy in congenital skeletal polydystrophy 10 decasomy Ten copies of a chromosome, 2n + 8 decasomy 8 in histolytic carcinoma
Polysomy
Peritomy
Tetrasomy
Prosection
Monoxenous development
Spinal fusion
Vishnevsky liniment
Spooning