BSND

Reviewed February 2011

What is the official name of the BSND gene?

The official name of this gene is “Bartter syndrome, infantile, with sensorineural deafness (Barttin).”

BSND is the gene's official symbol. The BSND gene is also known by other names, listed below.

What is the normal function of the BSND gene?

The BSND gene provides instructions for making a protein called barttin. This protein is found primarily in the kidneys, where it attaches (binds) to two specific chloride channels: ClC-Ka (produced from the CLCNKA gene) and ClC-Kb (produced from the CLCNKB gene). The ClC-Ka and ClC-Kb channels transport charged atoms of chlorine (chloride ions) out of kidney cells.

Barttin is essential for the normal placement of ClC-Ka and ClC-Kb channels in the cell membrane. It also regulates the channels' stability and function. The transport of chloride ions is part of the mechanism by which the kidneys reabsorb salt (sodium chloride or NaCl) from the urine back into the bloodstream. The retention of salt affects the body's fluid levels and helps maintain blood pressure.

Barttin, ClC-Ka, and ClC-Kb are also found in the inner ear, where they play a role in normal hearing.

How are changes in the BSND gene related to health conditions?

Bartter syndrome - caused by mutations in the BSND gene

More than a dozen mutations in the BSND gene have been identified in people with Bartter syndrome type IV. This form of the disorder causes severe or life-threatening health problems that become apparent before or soon after birth. Affected individuals also have hearing loss caused by abnormalities in the inner ear, which is why Bartter syndrome type IV is also known as antenatal Bartter syndrome with sensorineural deafness.

BSND gene mutations impair barttin's ability to regulate the ClC-Ka and ClC-Kb channels. Some mutations keep the channels from ever reaching the cell membrane. Other mutations allow the channels to reach the cell membrane but prevent them from transporting ions properly. As a result, the kidneys cannot reabsorb salt normally and excess salt is lost through the urine (salt wasting). The abnormal salt loss disrupts the normal balance of ions in the body. This imbalance underlies many of the major features of Bartter syndrome, including a failure to grow and gain weight at the expected rate (failure to thrive), dehydration, constipation, and increased urine production (polyuria). A loss of ClC-Ka and ClC-Kb function in the inner ear is responsible for the hearing loss characteristic of Bartter syndrome type IV.

Where is the BSND gene located?

Cytogenetic Location: 1p32.1

Molecular Location on chromosome 1: base pairs 55,464,616 to 55,474,464

The BSND gene is located on the short (p) arm of chromosome 1 at position 32.1.

More precisely, the BSND gene is located from base pair 55,464,616 to base pair 55,474,464 on chromosome 1.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about BSND?

You and your healthcare professional may find the following resources about BSND helpful.

Educational resources - Information pages
National Institute of Diabetes and Digestive and Kidney Diseases: The Kidneys and How They Work (http://kidney.niddk.nih.gov/Kudiseases/pubs/yourkidneys/)
Genetic Testing Registry - Repository of genetic test information
- GTR: Genetic tests for BSND (http://www.ncbi.nlm.nih.gov/gtr/tests/?term=7809%5Bgeneid%5D)

You may also be interested in these resources, which are designed for genetics professionals and researchers.

PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=((BSND%5BTIAB%5D)%20OR%20(barttin%5BTIAB%5D))%20OR%20(DFNB73%5BTIAB%5D)%20AND%20((Genes%5BMH%5D)%20OR%20(Genetic%20Phenomena%5BMH%5D))%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D%20AND%20%22last%203600%20days%22%5Bdp%5D)
OMIM - Genetic disorder catalog (http://omim.org/entry/606412)
Research Resources - Tools for researchers
- Entrez Gene (http://www.ncbi.nlm.nih.gov/gene/7809)
- GeneCards (http://www.genecards.org/cgi-bin/carddisp.pl?id_type=entrezgene&id=7809)
- HUGO Gene Nomenclature Committee (http://www.genenames.org/data/hgnc_data.php?hgnc_id=16512)

What other names do people use for the BSND gene or gene products?

BART
barttin
BSND_HUMAN
deafness, autosomal recessive 73
DFNB73

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding BSND?

autosomal ; autosomal recessive ; cell ; cell membrane ; chloride ; chloride channels ; constipation ; dehydration ; failure to thrive ; gene ; ions ; kb ; kidney ; NaCl ; polyuria ; protein ; recessive ; sensorineural ; sodium ; sodium chloride ; subunit ; syndrome ; wasting

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

Birkenhäger R, Otto E, Schürmann MJ, Vollmer M, Ruf EM, Maier-Lutz I, Beekmann F, Fekete A, Omran H, Feldmann D, Milford DV, Jeck N, Konrad M, Landau D, Knoers NV, Antignac C, Sudbrak R, Kispert A, Hildebrandt F. Mutation of BSND causes Bartter syndrome with sensorineural deafness and kidney failure. Nat Genet. 2001 Nov;29(3):310-4. (http://www.ncbi.nlm.nih.gov/pubmed/11687798?dopt=Abstract)
Entrez Gene (http://www.ncbi.nlm.nih.gov/gene/7809)
Estévez R, Boettger T, Stein V, Birkenhäger R, Otto E, Hildebrandt F, Jentsch TJ. Barttin is a Cl- channel beta-subunit crucial for renal Cl- reabsorption and inner ear K+ secretion. Nature. 2001 Nov 29;414(6863):558-61. (http://www.ncbi.nlm.nih.gov/pubmed/11734858?dopt=Abstract)
Hayama A, Rai T, Sasaki S, Uchida S. Molecular mechanisms of Bartter syndrome caused by mutations in the BSND gene. Histochem Cell Biol. 2003 Jun;119(6):485-93. Epub 2003 May 22. (http://www.ncbi.nlm.nih.gov/pubmed/12761627?dopt=Abstract)
Janssen AG, Scholl U, Domeyer C, Nothmann D, Leinenweber A, Fahlke C. Disease-causing dysfunctions of barttin in Bartter syndrome type IV. J Am Soc Nephrol. 2009 Jan;20(1):145-53. doi: 10.1681/ASN.2008010102. Epub 2008 Sep 5. (http://www.ncbi.nlm.nih.gov/pubmed/18776122?dopt=Abstract)
Krämer BK, Bergler T, Stoelcker B, Waldegger S. Mechanisms of Disease: the kidney-specific chloride channels ClCKA and ClCKB, the Barttin subunit, and their clinical relevance. Nat Clin Pract Nephrol. 2008 Jan;4(1):38-46. Review. (http://www.ncbi.nlm.nih.gov/pubmed/18094726?dopt=Abstract)
Miyamura N, Matsumoto K, Taguchi T, Tokunaga H, Nishikawa T, Nishida K, Toyonaga T, Sakakida M, Araki E. Atypical Bartter syndrome with sensorineural deafness with G47R mutation of the beta-subunit for ClC-Ka and ClC-Kb chloride channels, barttin. J Clin Endocrinol Metab. 2003 Feb;88(2):781-6. (http://www.ncbi.nlm.nih.gov/pubmed/12574213?dopt=Abstract)
Riazuddin S, Anwar S, Fischer M, Ahmed ZM, Khan SY, Janssen AG, Zafar AU, Scholl U, Husnain T, Belyantseva IA, Friedman PL, Riazuddin S, Friedman TB, Fahlke C. Molecular basis of DFNB73: mutations of BSND can cause nonsyndromic deafness or Bartter syndrome. Am J Hum Genet. 2009 Aug;85(2):273-80. doi: 10.1016/j.ajhg.2009.07.003. Epub 2009 Jul 30. (http://www.ncbi.nlm.nih.gov/pubmed/19646679?dopt=Abstract)
Scholl U, Hebeisen S, Janssen AG, Müller-Newen G, Alekov A, Fahlke C. Barttin modulates trafficking and function of ClC-K channels. Proc Natl Acad Sci U S A. 2006 Jul 25;103(30):11411-6. Epub 2006 Jul 18. (http://www.ncbi.nlm.nih.gov/pubmed/16849430?dopt=Abstract)

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.



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