Table 1.

Pharmacological classification of Bartter syndrome with important clinical features.

Subtypes	Gene loci	Molecule affected	Molecule implicated	Site in renal tubule	Pharmacological classification	Important clinical features
Antenatal Bartter syndrome	I (601678)	SLC12A1/15q21.1	Na-K-2Cl cotransporter	TAL	Pure frusemide type	Severe maternal polyhydramnios, hypercalciuria, nephrocalcinosis
Antenatal Bartter syndrome	II (241200)	KCNJ1/11q24	Kir1.1 potassium channel	TAL	Thiazide type	Hypochloremia, hypomagnesemia, failure to thrive in infancy, EAST syndrome
Classic Bartter	III (602522)	CLCNKB/1p36	ClC-Kb chloride channel	DCT	Thiazide type	Hypomagnesemia, hypocalciuria, EAST syndrome
Bartter syndrome with senosorineural deafness	IV (606412)	BSND/1p31 or CLCNKA- CLCNKB/1p36	Barttin, ClC-Ka and ClC-Kb chloride channels	TAL+DCT	Thiazide-frusemide type	Polyuria, hypochloremia, mild hypomagnesemia, SND, CRF

TAL: thick ascending loop of Henle, TAL: thin ascending loop of Henle, DCT: distal cortical tubule, EAST syndrome: epilepsy, ataxia, sensorineural deafness, tubulopathy, SND: sensorineural deafness, and CRF: chronic renal failure.