Genetic disorders

    ➢ Barrter syndrome: normal magnesium levels are commonly observed, other common findings include young age, failure to thrive, and polyuria

    ➢ Mutations in the KCNJ10 gene coding for the KCNJ10/Kir4 (an autosomal resessive disorder characterized by the EAST syndrome [epilepsy, ataxia, sensozineural deafness and tubulopathy])

    ➢ Mutations in HNF1β gene coding for the transcription factor HNF1-β (dominant mode of inheritance). Other clinical manifestations are common (early renal disease, renal cysts, maternity onset diabetes mellitus, increased transaminases and urogenital malformations)

Acquired disorders

    ➢ Diuretics abuse: a urine screen for diuretics is useful

    ➢ Bulimia nervosa and chronic vomiting: urinary chloride levels are usually < 25 mEq/L

    ➢ Autoimmune disorders such as sjogren's Syndrome (appropriate tests are necessary)

    ➢ Drugs such as cisplatin: drug history is mandatory