Chromosome 20 (human)
Chromosome 20 is one of the 23 pairs of chromosomes in humans. Chromosome 20 spans around 63 million base pairs (the building material of DNA) and represents between 2 and 2.5 percent of the total DNA in cells. Chromosome 20 was fully sequenced in 2001 and was reported to contain over 59 million base pairs representing 99.4% of the euchromatic DNA.  Since then, due to sequencing improvements and fixes, the length of chromosome 20 has been updated to just over 63 million base pairs.

# Genes
The following are some of the gene count estimates of human chromosome 20. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project (CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes.
The following are some of the genes located on chromosome 20:
- ADA: Adenosine Deaminase (Adenosine Deaminase Deficiency)
- ANDP: encoding protein Activity-dependent neuroprotector homeobox
- AHCY: S-adenosylhomocysteine hydrolase
- ARFGEF2: ADP-ribosylation factor guanine nucleotide-exchange factor 2 (brefeldin A-inhibited)
- BCAS1: Breast carcinoma-amplified sequence 1
- BLCAP: Bladder cancer associated protein
- BMP2: Bone Morphogenetic Protein 2 (osteoblast differentiation)
- BPIFB1: encoding protein BPI fold containing family B, member 1
- BPIFB4: encoding protein BPI fold containing family B, member 4
- C20orf132: encoding protein Uncharacterized protein C20orf132
- C20orf27: encoding protein UPF0687 protein C20orf27
- C20orf3: encoding protein Adipocyte plasma membrane-associated protein
- C20orf43: encoding protein UPF0549 protein C20orf43
- CSRP2BP: encoding protein CSRP2 binding protein
- CST9L: Cystatin-9-like
- CSTL1: Cystatin-like 1
- CTCFL: CCCTC-binding factor-like
- CTNNBL1: Beta-catenin-like protein 1
- DBNDD2: Dysbindin domain-containing protein 2
- DDX27: DEAD box polypeptide 27
- DEFB118, DEFB119, DEFB126, DEFB127, DEFB129: Beta-defensin genes
- DLGAP4: Disks large-associated protein 4
- DNAJC5: Cysteine string protein
- EDEM2: ER degradation-enhancing alpha-mannosidase-like 2
- EDN3: endothelin 3
- ENTPD6: Ectonucleoside triphosphate diphosphohydrolase 6
- ESF1: ESF1 nucleolar pre-rRNA processing protein homolog
- FASTKD5: encoding protein FAST kinase domain-containing protein 5 (FASTKD5)
- FITM2: encoding protein Fat storage-inducing transmembrane protein 2
- GZF1: encoding protein GDNF-inducible zinc finger protein 1
- GMEB2: Glucocorticoid modulatory element-binding protein 2
- GNAS1: Gs alpha subunit (membrane G-protein)
- GSS: glutathione synthetase
- ITPA: encoding enzyme Inosine triphosphate pyrophosphatase
- JAG1: jagged 1 (Alagille syndrome)
- JPH2: encoding protein Junctophilin 2
- KIZ: encoding protein Kizuna centrosomal protein
- Kua-UEV:
- LIME1: encoding protein Lck-interacting transmembrane adapter 1
- LZTS3: encoding protein Leucine zipper, putative tumor suppressor family member 3
- NAPB: encoding protein Beta-soluble NSF attachment protein
- NOL5A: encoding protein Nucleolar protein 56
- NRSN2: encoding protein Neurensin-2
- OTOR: encoding protein Otoraplin
- PANK2: pantothenate kinase 2 (Hallervorden-Spatz syndrome)
- PKIG: encoding protein cAMP-dependent protein kinase inhibitor gamma
- PLAGL2: encoding protein Zinc finger protein PLAGL2
- POLR3F: encoding enzyme DNA-directed RNA polymerase III subunit RPC6
- PRIC285:
- PRNP: prion protein (p27-30) (CreutzfeldtJakob disease, Gerstmann-Strausler-Scheinker syndrome, fatal familial insomnia)
- PXMP4: encoding protein Peroxisomal membrane protein 4
- R3HDML: encoding protein R3H domain containing-like
- SALL4: sal-like 4 (Drosophila)
- SERINC3: encoding protein Serine incorporator 3
- SLC2A4RG: encoding protein SLC2A4 regulator
- SLX4IP: encoding protein SLX4 interacting protein
- SPATA2: encoding protein Spermatogenesis-associated protein 2
- SPEF1: encoding protein Sperm flagellar protein 1
- SRXN1: encoding protein Sulfiredoxin-1
- STAU1: encoding protein Double-stranded RNA-binding protein Staufen homolog 1
- STK35L1: encoding protein STK35L1
- SUN5: encoding protein SUN domain-containing protein 5
- TASP1: encoding enzyme Threonine aspartase 1
- tTG: tissue transglutaminase (auto antigen of Celiac disease)
- TMEPAI: encoding protein Transmembrane prostate androgen-induced protein
- TTPAL: encoding protein Tocopherol (alpha) transfer protein-like
- UCKL1: encoding enzyme Uridine-cytidine kinase-like 1
- UQCC: encoding enzyme Ubiquinol-cytochrome c reductase complex chaperone CBP3 homolog
- VAPB: VAMP (vesicle-associated membrane protein)-associated protein B and C
- YTHDF1: encoding protein YTH domain family, member 1
- ZFP64 encoding protein Zinc finger protein 64 homolog, isoforms 1 and 2
- ZGPAT: encoding protein Zinc finger CCCH-type with G patch domain-containing protein
- ZHX3: encoding protein Zinc fingers and homeoboxes protein 3
- ZNF334: encoding protein Zinc finger protein 334
- ZNF343: encoding protein Zinc finger protein 343
- ZSWIM3: encoding protein Zinc finger SWIM-type containing 3
- ZMYND8: encoding enzyme Protein kinase C-binding protein 1
- ZNF133: encoding protein Zinc finger protein 133

# Diseases and disorders
The following diseases are some of those related to genes on chromosome 20:
- Albright's hereditary osteodystrophy
- Arterial tortuosity syndrome
- Adenosine deaminase deficiency
- Alagille syndrome
- Fatal familial insomnia
- Galactosialidosis - CTSA
- Maturity onset diabetes of the young type 1
- Neuronal ceroid lipofuscinosis
- Pantothenate kinase-associated neurodegeneration
- Transmissible spongiform encephalopathy (prion diseases)
- Waardenburg syndrome

# Cytogenetic band