Short stature homeobox gene

The short stature homeobox (SHOX) gene is a gene, located on both the X and Y chromosomes, which is associated with short stature in humans if mutated or present in only one copy (haploinsufficiency).

Pathology

The gene was first found during a search for the cause of short stature in women with Turner syndrome, in which there is loss of genetic material from the X chromosome, classically by loss of one entire X chromosome.

Since its discovery, the SHOX gene has been found to play a role in idiopathic short stature (short stature of unknown cause without other symptoms), Léri-Weill dyschondrosteosis, and Langer mesomelic dysplasia.

Gene dosage effects of extra copies of SHOX may be a cause of the increased stature seen in other sex chromosome aneuploidy conditions such as 47,XXX, 47,XYY, 47,XXY, 48,XXYY, etc.

Function

The SHOX gene is a homeobox gene, meaning that it helps regulate development. The SHOX gene is composed of 6 different exons and is located in the pseudoautosomal region (PAR1) of the X chromosome and Y chromosome. Experiments have found similar genes in a variety of animals and insects.

SHOX2

Short stature homeobox 2, also known as homeobox protein Og12X or paired-related homeobox protein SHOT, is a protein that in humans is encoded by the SHOX2 gene.

Function

SHOX2 is a member of the homeobox family of genes that encode proteins containing a 60-amino acid residue motif that represents a DNA-binding domain. Homeobox proteins have been characterized extensively as transcriptional regulators involved in pattern formation in both invertebrate and vertebrate species.

Clinical significance

Several human genetic disorders are caused by aberrations in human homeobox genes. This locus represents a pseudoautosomal homeobox gene that is thought to be responsible for idiopathic short stature, and it is implicated in the short stature phenotype of Turner syndrome patients. This gene is considered to be a candidate gene for Cornelia de Lange Syndrome.

SHOX2 localises on chromosome 3, so it is an autosomal and not a pseudoautosomal homeobox (SHOX, which localises on the PAR1 region of chromosome X and Y, has a pseudoautosomal hereditability).