Short stature homeobox gene
Encyclopedia
Short stature homeobox gene or SHOX is a gene
on the X chromosome
and Y chromosome
which is associated with short stature
in humans if mutated or present in only one copy (haploinsufficiency
).
, 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.
s 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.
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
on the X chromosome
X chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
and Y chromosome
Y chromosome
The Y chromosome is one of the two sex-determining chromosomes in most mammals, including humans. In mammals, it contains the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 60 million base pairs...
which is associated with short stature
Short stature
Short stature refers to a height of a human being which is below expected. Shortness is a vague term without a precise definition and with significant relativity to context...
in humans if mutated or present in only one copy (haploinsufficiency
Haploinsufficiency
Haploinsufficiency occurs when a diploid organism only has a single functional copy of a gene and the single functional copy of the gene does not produce enough of a gene product to bring about a wild-type condition, leading to an abnormal or diseased state...
).
Pathology
The gene was first found during a search for the cause of short stature in women with Turner syndromeTurner syndrome
Turner syndrome or Ullrich-Turner syndrome encompasses several conditions in human females, of which monosomy X is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent...
, 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
Léri-Weill dyschondrosteosis
Léri-Weill dyschondrosteosis or LWD is a rare genetic disorder which results in dwarfism with short forearms and legs and a particular deformity of the forearms .-Causes:...
, and Langer mesomelic dysplasia.
Gene dosage
Gene dosage
Gene dosage is the number of copies of a gene present in a cell or nucleus. An increase in gene dosage can cause higher levels of gene product if the gene is not subject to regulation from elsewhere in the body....
effects of extra copies of SHOX may be a cause of the increased stature seen in other sex chromosome aneuploidy
Aneuploidy
Aneuploidy is an abnormal number of chromosomes, and is a type of chromosome abnormality. An extra or missing chromosome is a common cause of genetic disorders . Some cancer cells also have abnormal numbers of chromosomes. Aneuploidy occurs during cell division when the chromosomes do not separate...
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 exonExon
An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule either after portions of a precursor RNA have been removed by cis-splicing or when two or more precursor RNA molecules have been ligated by trans-splicing. The mature RNA molecule can be a messenger RNA...
s and is located in the pseudoautosomal region
Pseudoautosomal region
The pseudoautosomal regions, PAR1 and PAR2 are homologous sequences of nucleotides on the X and Y chromosomes.The pseudoautosomal regions get their name because any genes located within them are inherited just like any autosomal genes...
(PAR1) of the X chromosome and Y chromosome. Experiments have found similar genes in a variety of animals and insects.