Chromosome 22

Chromosome 22 (human)
Pair of human chromosome 22 (after G-banding). One is from mother, one is from father.
Chromosome 22 pair in human male karyogram.
Features
Length (bp)	51,304,566
Number of genes	956 1,110
Type	Autosome
Centromere position	Acrocentric
Identifiers
RefSeq	NC_000022
GenBank	CM000684

Chromosome 22 is one of the 23 pairs of chromosomes in human cells. Humans normally have two copies of chromosome 22 in each cell. Chromosome 22 is the second smallest human chromosome (chromosome 21 being smaller), spanning about 49 million DNA base pairs and representing between 1.5 and 2% of the total DNA in cells.

In 1999, researchers working on the Human Genome Project announced they had determined the sequence of base pairs that make up this chromosome. Chromosome 22 was the first human chromosome to be fully sequenced.

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 33%, with one estimate giving 956 genes, and the other estimate giving 1,110 genes.

Chromosome 22 was originally identified as the smallest chromosome. After extensive research, however, researchers concluded that chromosome 21 was smaller. The numbering of these chromosomes wasn't rearranged because of chromosome 21 being known by that designation as the chromosome that can lead to Down syndrome.

The following are some of the genes located on chromosome 22:

The following diseases are some of those related to genes on chromosome 22:

The following conditions are caused by changes in the structure or number of copies of chromosome 22: