Chromosome 20 represents approximately 2% of the total DNA in cells.
|Summary:||Gene examples of chromosome 20:|
|SALL4: This gene belongs to the SALL gene family, whose members act as transcription factors and are involved in the formation of tissues and organs before birth. Transcription factors are proteins that bind to specific regions of DNA and help control the activity of particular genes. Mutations in the SALL4 gene can lead to Duane anomaly (limiting outward and inward eye movement resulting from improper development of certain nerves that control eye movement), radial ray malformations (bone abnormalities in hands and arms) and other features of Duane-radial ray syndrome.||The PRNP gene encodes a protein called the prion protein (PrP), whose exact function is unknown. Mutations in this gene have been associated with Creutzfeldt-Jakob disease, fatal familial insomnia, Gerstmann-Sträussler-Scheinker disease, Huntington disease-like 1 and kuru. These diseases affect the brain and nervous system causing memory changes, personality changes and problems with movement that worsen over time.|