Chromosome 5 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 5 spans about 181 million base pairs (the building blocks of DNA) and represents almost 6% of the total DNA in cells. Chromosome 5 is the 5th largest human chromosomes, yet has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of non-coding and syntenic conservation with non-mammalian vertebrates, suggesting they are functionally constrained.
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 3%, with one estimate giving 2,578 genes, and the other estimate giving 2,505 genes.
Because chromosome 5 is responsible for many forms of growth and development (cell divisions) changes may cause cancers. One example would be acute myeloid leukemia (AML).
The following are some of the genes located on chromosome 5:
ABLIM3: encoding protein Actin-binding LIM protein 3
ADAMTS2: ADAM metallopeptidase with thrombospondin type 1 motif, 2
ANKRD31: encoding protein Ankyrin repeat domain 31
APBB3: encoding protein Amyloid beta A4 precursor protein-binding family B member 3
APC: adenomatosis polyposis coli
C5orf3: encoding protein FAM114A2
C5orf21/FAM172A: encoding protein UPF0528 protein FAM172A
CAST: Calpastatin
EGR1: early growth response protein 1
ERAP1: endoplasmic reticulum aminopeptidase 1 (previously called ARTS-1)
ERAP2: endoplasmic reticulum aminopeptidase 2
DTDST: diastrophic dysplasia sulfate transporter
ERCC8: excision repair cross-complementing rodent repair deficiency, complementation group 8
FGFR4: fibroblast growth factor receptor 4
GM2A: GM2 ganglioside activator
HEXB: hexosaminidase B (beta polypeptide)
HMGXB3: encoding protein HMG-box containing 3
IRX1: Iroquois-class homeodomain protein (human)
MASS1: monogenic, audiogenic seizure susceptibility 1 homolog (mouse)
MCCC2: methylcrotonoyl-Coenzyme A carboxylase 2 (beta)
MEF2C: Myocyte-specific enhancer factor 2C
MTRR: 5-methyltetrahydrofolate-homocysteine methyltransferase reductase
NIPBL: Nipped-B homolog (Drosophila)
NSD1: Transcription coregulator protein
Pikachurin: Responsible for the functioning of the ribbon synapses; allows the eye to track moving objects
PURA: PURINE-RICH ELEMENT-BINDING PROTEIN A
SLC22A5: solute carrier family 22 (organic cation transporter), member 5
SLC26A2: solute carrier family 26 (sulfate transporter), member 2
SH3TC2: domain and tetratricopeptide repeats 2
SMN1: survival motor neuron 1, telomeric
SMN2: survival motor neuron 2, centromeric
SNCAIP: synuclein, alpha interacting protein (synphilin)
SPINK5: serine protease inhibitor Kazal-type 5 (LEKTI)
SPINK6: serine protease inhibitor Kazal-type 6
SPINK9: serine protease inhibitor Kazal-type 9 (LEKTI-2)
TCOF1: Treacher Collins-Franceschetti syndrome 1
TGFBI: keratoepithelin
TTC37: Tetratricopeptide repeat domain 37
UPF0488: encodes G protein-coupled receptor protein signaling pathway
FGF1: fibroblast growth factor 1 (acidic fibroblast growth factor)
Diseases and disorders
The following are some of the diseases related to genes located on chromosome 5:
Achondrogenesis type 1B
Atelosteogenesis, type II
Charcot–Marie–Tooth disease, type 4
Cockayne syndrome
Cornelia de Lange syndrome
Corneal dystrophy of Bowman layer, type I
Corneal dystrophy of Bowman layer, type II
Cri du Chat
Diastrophic dysplasia
Ehlers-Danlos syndrome
Ehlers-Danlos syndrome, dermatosparaxis type
Familial adenomatous polyposis
Granular corneal dystrophy type I
Granular corneal dystrophy type II
GM2-gangliosidosis, AB variant
Homocystinuria
3-Methylcrotonyl-CoA carboxylase deficiency
Myelodysplastic Syndrome
Netherton syndrome
Nicotine dependency
Parkinson's disease
Primary carnitine deficiency
Recessive multiple epiphyseal dysplasia
Sandhoff disease
Spinal muscular atrophy
Sotos Syndrome
Survival motor neuron spinal muscular atrophy
Treacher Collins syndrome
Tricho-hepato-enteric syndrome
Usher syndrome
Usher syndrome type II
The following conditions are caused by changes in the structure or number of copies of chromosome 5:
Cri-du-chat syndrome is caused by a deletion of the end of the short (p) arm of chromosome 5. This chromosomal change is written as 5p-. The signs and symptoms of cri-du-chat syndrome are probably related to the loss of multiple genes in this region. Researchers have not identified all of these genes or determined how their loss leads to the features of the disorder. They have discovered, however, that a larger deletion tends to result in more severe mental retardation and developmental delays in people with cri-du-chat syndrome.
Researchers have defined narrow regions of the short arm of chromosome 5 that are associated with particular features of cri-du-chat syndrome. A specific region designated 5p15.3 is associated with a cat-like cry, and a nearby region called 5p15.2 is associated with mental retardation, small head (microcephaly), and distinctive facial features.
Familial Adenomatous Polyposis is caused by a deletion of the APC tumor suppressor gene on the long (q) arm of chromosome 5. This chromosomal change results in thousands of colonic polyps which gives the patient a 100% risk of colon cancer if total colectomy is not done.
Chromosome 5q deletion syndrome is caused by the deletion of the q arm (long arm) of chromosome 5. This deletion has been linked to several blood related disorders including Myelodysplastic syndrome and Erythroblastopenia. This is a different condition than Cri-du-chat which was mentioned above.
Other changes in the number or structure of chromosome 5 can have a variety of effects, including delayed growth and development, distinctive facial features, birth defects, and other medical problems. Changes to chromosome 5 include an extra segment of the short (p) or long (q) arm of the chromosome in each cell (partial trisomy 5p or 5q), a missing segment of the long arm of the chromosome in each cell (partial monosomy 5q), and a circular structure called ring chromosome 5. A ring chromosome occurs when both ends of a broken chromosome are reunited.
