Chromosome 20 (human)



Chromosome 20 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 20 spans more than 63 million base pairs (the building material of DNA) and represents between 2 and 2.5 percent of the total DNA in cells.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 20 likely contains between 600 and 800 genes.

Genes
The following are some of the genes located on chromosome 20:
 * EDN3: endothelin 3
 * JAG1: jagged 1 (Alagille syndrome)
 * PANK2: pantothenate kinase 2 (Hallervorden-Spatz syndrome)
 * PRNP: prion protein (p27-30) (Creutzfeld-Jakob disease, Gerstmann-Strausler-Scheinker syndrome, fatal familial insomnia)

Diseases
The following diseases are some of those related to genes on chromosome 20:
 * Alagille syndrome
 * Maturity onset diabetes of the young type 1
 * pantothenate kinase-associated neurodegeneration
 * prion disease
 * Waardenburg syndrome