Scientific background:

Summary: Chloride channel B is located in the thick ascending loop of Henle. Functional defects in this ion channel result in classic Bartter syndrome.

Epidemiology: Although exact data are not available, mutation in this gene are thought to occur 1 in 50,000-100,000 newborn.

Methodology:

	clinical test	Method		Genomic sequencing of the entire coding region
		Turn-around time		25 working days
		Effort		medium
		Specimen		DNA
		Quality assessment		Internal quality control only
	All known and new missense, nonsense and splice mutations can be detected.
	clinical test	Method		Multiplex Ligation-Dependent Probe Amplification
		Turn-around time		25 working days
		Effort		medium
		Specimen		DNA
		Quality assessment		Internal quality control only
	clinical test	Method		Carrier testing
		Turn-around time		5 working days
		Effort		little
		Specimen		DNA
		Quality assessment		Internal quality control only
	The test is only specific about the mutation already known in this kindred.

Literature: 

Tajima T et al. (2006) Molecular analysis of the CLCNKB gene in Japanese patients with classic Bartter syndrome.
Bettinelli A et al. (2005) Simultaneous mutations in the CLCNKB and SLC12A3 genes in two siblings with phenotypic heterogeneity in classic Bartter syndrome.
Shaer AJ et al. (2001) Inherited primary renal tubular hypokalemic alkalosis: a review of Gitelman and Bartter syndromes.