Reviewed May 2006
What is the official name of the SLC5A5 gene?
The official name of this gene is “solute carrier family 5 (sodium iodide symporter), member 5.”
SLC5A5 is the gene's official symbol. The SLC5A5 gene is also known by other names, listed below.
What is the normal function of the SLC5A5 gene?
The SLC5A5 gene provides instructions for making a protein called sodium-iodide symporter or NIS. In certain tissues, this protein facilitates the uptake of iodide (a negatively charged version of iodine). The NIS protein is found primarily in the thyroid gland, a butterfly-shaped tissue in the lower neck. The thyroid gland produces and releases iodide-containing thyroid hormones that play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism). The NIS protein supports a remarkably efficient system that ensures iodine from the diet accumulates in the thyroid gland for the production of thyroid hormones. This system depends on the NIS protein being positioned in the cell membrane, so it can transport iodide from the bloodstream into particular thyroid cells called follicular cells.
In addition to the thyroid gland, the NIS protein is found in breast tissue during milk production (lactation), ovaries, salivary glands, certain stomach cells (parietal cells), tear glands (lacrimal glands), and a part of the brain called the choroid plexus. During lactation, the NIS protein transports iodide into the milk to supply breast-fed infants with this critical component of thyroid hormones.
Does the SLC5A5 gene share characteristics with other genes?
The SLC5A5 gene belongs to a family of genes called SLC (solute carriers).
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? in the Handbook.
How are changes in the SLC5A5 gene related to health conditions?
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congenital hypothyroidism - caused by mutations in the SLC5A5 gene
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Several SLC5A5 mutations have been identified in people with congenital hypothyroidism. About half of these mutations delete part of the SLC5A5 gene or disrupt protein production, resulting in an abnormally small, nonfunctional protein. The remaining mutations change one of the building blocks (amino acids) used to make the NIS protein. Some amino acid substitutions prevent the NIS protein from being positioned in the cell membrane, disabling iodide transport. Other amino acid substitutions do not affect the membrane location of the NIS protein but change the protein's 3-dimensional shape, which impairs its function.
SLC5A5 mutations reduce or prevent iodide transport. As a result, the thyroid gland cannot accumulate iodide efficiently, which decreases the production of thyroid hormones. The signs and symptoms of congenital hypothyroidism range from mild to severe depending on the level of hormone production. In many cases, the thyroid gland is enlarged (goiter) in an attempt to compensate for reduced hormone production.
Where is the SLC5A5 gene located?
Cytogenetic Location: 19p13.2-p12
Molecular Location on chromosome 19: base pairs 17,843,781 to 17,865,896
The SLC5A5 gene is located on the short (p) arm of chromosome 19 between positions 13.2 and 12.
More precisely, the SLC5A5 gene is located from base pair 17,843,781 to base pair 17,865,896 on chromosome 19.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about SLC5A5?
You and your healthcare professional may find the following resources about SLC5A5 helpful.
- Gene Tests - DNA tests ordered by healthcare professionals
You may also be interested in these resources, which are designed for genetics professionals and researchers.
- PubMed - Recent literature
- OMIM - Genetic disorder catalog
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What other names do people use for the SLC5A5 gene or gene products?
- NIS
- SC5A5_HUMAN
- sodium-iodide symporter
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding SLC5A5?
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? in the Handbook.