In humans, the autosome that spans about 49 million base pairs, likely to contain about 400 to 500 genes, and is an acrocentric chromosome
In humans, the chromosomes occur in pairs and a typical somatic cell would contain 23 pairs of chromosomes in the nucleus. Each of these pairs has a characteristic length and banding pattern. There are two types of chromosomes: autosomes and allosomes. There are also two sets: the first set comes from the mother and the second set, from the father. Using idiograms, each chromosome may be identified one from the other based on the relative size and the banding pattern.
Chromosome 22 is an acrocentric autosome. It spans almost 49 million base pairs (i.e. about 1.5 to 2 % of the total DNA). It is likely to contain about 400 to 500 genes. This is the first human chromosome to be fully sequenced. It is regarded as the second smallest human autosome (chromosome 21 as the smallest). Some of the genes located on chromosome 22 are PI4KA (encoding for the enzyme Phosphatidylinositol 4-kinase alpha), SYNGR1 (for synaptogyrin-1), and TEF (for thyrotroph embryonic factor).
Some of the diseases and disorders related to the genes on chromosome 22 include cat eye syndrome, DiGeorge Syndrome, Emanuel syndrome, Rubinstein-Taybi syndrome, and schizophrenia.