BSND Gene - Barttin CLCNK Type Accessory Subunit Beta
Essential subunit of chloride channels, critical for renal and inner ear function
Gene Information Card
| Symbol | BSND |
|---|---|
| Full Name | Barttin CLCNK Type Accessory Subunit Beta |
| Gene Type | Protein coding |
| Chromosomal Location | 1p32.3 |
| NCBI Gene ID | 7804 ncbi.nlm.nih.gov/gene/7804 |
| Ensembl ID | ENSG00000198959 |
| UniProt ID | Q8WZ55 |
| OMIM ID | 606412 |
| HGNC ID | 16512 |
| Aliases | Barttin, DFNB73 |
Description
The BSND gene encodes barttin, a beta subunit essential for the proper trafficking and function of CLCNKA and CLCNKB chloride channels. Barttin is required for chloride transport in the kidney's thick ascending limb of Henle and in the inner ear's marginal cells of the stria vascularis. Loss-of-function mutations cause Bartter syndrome type 4, characterized by renal salt wasting, sensorineural deafness, and electrolyte imbalances.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Bartter syndrome type 4 (BSND) | Loss-of-function mutations in BSND disrupt barttin-mediated trafficking of CLCNKA/CLCNKB channels, impairing renal chloride reabsorption and endocochlear potential generation. | OMIM #602522; ClinVar; multiple case reports |
| Deafness, autosomal recessive 73 (DFNB73) | BSND mutations cause sensorineural hearing loss due to defective chloride transport in the inner ear, leading to loss of endocochlear potential. | OMIM #613865; ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | Medium |
| Inner ear (cochlea) | 8.2 | Medium |
| Pancreas | 1.3 | Low |
| Liver | 0.5 | Not detected |
| Brain | 0.2 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 15.0 | High expression in transfected cells |
| HK-2 (kidney proximal tubule) | 9.8 | Endogenous expression |
| HeLa | 0.1 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, no protein production |
| c.139G>A (p.Gly47Arg) | Missense | Rare | Impaired barttin trafficking, loss of function |
| c.226C>T (p.Arg76Trp) | Missense | Rare | Disrupts CLCNKB interaction, loss of function |
| c.389G>A (p.Trp130*) | Nonsense | Rare | Premature stop, truncated protein, loss of function |
Mutation functional classification
Loss of Function (LOF)
All reported pathogenic BSND mutations are loss-of-function, leading to impaired chloride channel trafficking or activity.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • chloride channel activity (GO:0005254) | • basolateral plasma membrane (GO:0016323) |
| • cytoplasmic vesicle membrane (GO:0030659) | • response to drug (GO:0042493) |
| • response to stimulus (GO:0050896) | • protein localization to plasma membrane (GO:0072659) |
Pathways
• REACT:14797 - Chloride channel activity
• REACT:14800 - Ion transport by P-type ATPases
• REACT:14801 - Transport of inorganic cations/anions
Protein Summary
Barttin is a 320-amino acid transmembrane protein with two predicted transmembrane domains. It functions as an essential beta subunit for CLCNKA and CLCNKB chloride channels, facilitating their exit from the endoplasmic reticulum and targeting to the basolateral membrane in renal epithelial cells and to the apical membrane in inner ear marginal cells. Barttin is critical for maintaining chloride homeostasis and endocochlear potential.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BSND Knockout HEK293 Cell Line | EDJ-KQ6126 | Human | 7809 | Details Get a Quote |
| BSND Knockout HeLa Cell Line | EDJ-KQ54798 | Human | 7809 | Details Get a Quote |
| BSND Knockout A-549 Cell Line | EDJ-KQ63290 | Human | 7809 | Details Get a Quote |
| BSND Knockout HCT 116 Cell Line | EDJ-KQ71757 | Human | 7809 | Details Get a Quote |
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