|http://ghr.nlm.nih.gov/ A service of the U.S. National Library of Medicine®|
The official name of this gene is “ALX homeobox 4.”
ALX4 is the gene's official symbol. The ALX4 gene is also known by other names, listed below.
The ALX4 gene provides instructions for producing a protein that is necessary for proper development throughout the body, especially in the skull and limb bones. The ALX4 protein is a transcription factor, which means it attaches (binds) to specific regions of DNA and helps control the activity of certain genes. The presence of the ALX4 protein seems to be particularly critical for the complete development of the skull.
The ALX4 gene belongs to a family of genes called homeobox (homeoboxes).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
A few mutations in the ALX4 gene have been identified in people with enlarged parietal foramina type 2. This condition is characterized by enlarged openings (foramina) in the two bones that make up much of the top and sides of the skull (the parietal bones). The mutations involved in this condition include a change of one protein building block (amino acid) in the ALX4 protein and deletions of one or more DNA building blocks (nucleotides) from the gene. These genetic changes result in the production of an unstable ALX4 protein that cannot bind to DNA. A nonfunctional ALX4 protein impairs the regulation of cell growth and division (proliferation); cell maturation and specialization (differentiation); and the balance of cell survival and self-destruction in certain areas of the skull. These impairments of cell function lead to problems with bone formation (ossification) in the skull, which cause enlarged parietal foramina.
A mutation resulting in the deletion of the ALX4 gene causes a condition called Potocki-Shaffer syndrome. People with this condition have enlarged parietal foramina (described above) and multiple benign bone tumors (exostoses). Other signs and symptoms seen in some people with Potocki-Shaffer syndrome include intellectual disability, developmental delay, distinctive facial features, vision problems, and defects in the heart, kidneys, and urinary tract.
Potocki-Shaffer syndrome (also called proximal 11p deletion syndrome) is caused by a deletion of genetic material from the short (p) arm of chromosome 11. In people with this condition, a loss of the ALX4 gene within this region is responsible for enlarged parietal foramina. This feature occurs because a shortage of the ALX4 transcription factor caused by deletion of the gene disrupts several cellular processes and impairs proper bone formation (ossification). The loss of another gene, EXT2, in the same region of chromosome 11 underlies the multiple exostoses. The loss of additional genes in the deleted region likely contributes to the other features of Potocki-Shaffer syndrome.
Cytogenetic Location: 11p11.2
Molecular Location on chromosome 11: base pairs 44,282,277 to 44,331,715
The ALX4 gene is located on the short (p) arm of chromosome 11 at position 11.2.
More precisely, the ALX4 gene is located from base pair 44,282,277 to base pair 44,331,715 on chromosome 11.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about ALX4 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
amino acid ; benign ; bone formation ; cell ; chromosome ; deletion ; developmental delay ; differentiation ; DNA ; exostoses ; gene ; homeobox ; homeodomain ; mutation ; ossification ; proliferation ; protein ; proximal ; syndrome ; transcription ; transcription factor
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.