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.
Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies. In January 2017, two estimates differed by 11%, with one estimate giving 956 genes, and the other estimate giving 1,068 genes.
The following are some of the genes located on chromosome 20:
ADA: Adenosine Deaminase (Adenosine Deaminase Deficiency)
AHCY: S-adenosylhomocysteine hydrolase
ARFGEF2: ADP-ribosylation factor guanine nucleotide-exchange factor 2 (brefeldin A-inhibited)
BMP2: Bone Morphogenetic Protein 2 (osteoblast differentiation)
C20orf3: encoding protein Adipocyte plasma membrane-associated protein
C20orf27: encoding protein UPF0687 protein C20orf27
C20orf43: encoding protein UPF0549 protein C20orf43
C20orf132: encoding protein Uncharacterized protein C20orf132
DNAJC5: Cysteine string protein
EDN3: endothelin 3
GSS: glutathione synthetase
GNAS1: Gs alpha subunit (membrane G-protein)
JAG1: jagged 1 (Alagille syndrome)
PANK2: pantothenate kinase 2 (Hallervorden-Spatz syndrome)
PRNP: prion protein (p27-30) (Creutzfeldt–Jakob disease, Gerstmann-Strausler-Scheinker syndrome, fatal familial insomnia)
tTG: tissue transglutaminase (auto antigen of Celiac disease)
SALL4: sal-like 4 (Drosophila)
VAPB: VAMP (vesicle-associated membrane protein)-associated protein B and C
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
