Chromosome 18
Chromosome 18 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 18 spans about 80 million base pairs (the building material of DNA) and represents about 2.5 percent of the total DNA in cells.

# Genes

## Number of genes
The following are some of the gene count estimates of human chromosome 18. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project (CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes.

## Gene list
The following is a partial list of genes on human chromosome 18. For complete list, see the link in the infobox on the right.
- ASXL3: encoding protein Additional sex combs like 3 (Drosophila)
- CABLES1: encoding protein CDK5 and ABL1 enzyme substrate 1
- CABYR: Calcium-binding tyrosine phosphorylation-regulated protein
- CHMP1B: Charged multivesicular body protein 1b
- CXXC1: CXXC-type zinc finger protein 1
- DCC: Deleted in Colorectal Cancer
- ELAC1: elaC ribonuclease Z 1
- ESCO1: encoding protein Establishment of sister chromatid cohesion N-acetyltransferase 1
- FAM69C: encoding protein Family with sequence similarity 69, member C
- FECH: ferrochelatase (protoporphyria)
- GREB1L: encoding protein Growth regulation by estrogen in breast cancer-like
- HAUS1: HAUS augmin-like complex subunit 1
- HDHD2: encoding enzyme Haloacid dehalogenase-like hydrolase domain-containing protein 2
- IER3IP1: encoding protein Immediate early response 3-interacting protein 1
- KC6: Keratoconus gene 6, discovery reported in 2005;
- MIR133A1: encoding microRNA MicroRNA 133a-1
- MIR187: encoding protein MicroRNA 187
- MRCL3: encoding protein Myosin regulatory light chain 12A
- NAPG: encoding protein Gamma-soluble NSF attachment protein
- NOL4: encoding protein Nucleolar protein 4
- NPC1: Niemann-Pick disease, type C1
- PIGN: encoding protein Phosphatidylinositol glycan anchor biosynthesis, class N
- PSTPIP2: encoding enzyme Proline-serine-threonine phosphatase-interacting protein 2
- RP11-267C16.1: encoding protein Uncharacterized LOC100287225
- SERPINB10: encoding protein Serpin peptidase inhibitor, clade B (ovalbumin), member 10
- SIGLEC15: encoding protein Sialic acid binding Ig-like lectin 15
- SMAD4: SMAD, mothers against DPP homolog 4 (Drosophila)
- TMEM241: encoding protein Transmembrane protein 241
- TTC39C: encoding protein Tetratricopeptide repeat protein 39C
- TWSG1: encoding protein Twisted gastrulation protein homolog 1
- ZCCHC2: encoding protein Zinc finger CCHC domain-containing protein 2
- ZFP161: encoding protein Zinc finger protein 161 homolog
- ZNF236: encoding protein Zinc finger protein 236
- ZNF516: encoding protein Zinc finger protein 516
- ZNF521: encoding protein Zinc finger protein 521
- ZNF532: encoding protein Zinc finger protein 532

# Diseases and disorders
The following diseases are some of those related to genes on chromosome 18:
- Erythropoietic protoporphyria
- Hereditary hemorrhagic telangiectasia
- Niemann-Pick disease Type C
- Porphyria
- Selective Mutism
- Edwards syndrome (Trisomy 18)
- Tetrasomy 18p
- Monosomy 18p
- Pitt Hopkins Syndrome 18q21
- Distal 18q- (distal deletion)
- Proximal 18q- (proximal deletion)

# Cytogenetic band