Enamel-renal syndrome associated with hypokalaemic metabolic alkalosis and impaired renal concentration: a novel syndrome?

Enamel-renal syndrome (ERS, OMIM204690) is char-acterized by amelogenesis imperfecta (AI) and nephro-calcinosis and has been previously reported in only10 cases (including four siblings) [1–7]. Cases diag-nosed as ERS sometimes show hypocalciuria [2,3,6]or impaired renal concentration [6] and occasionallyprogress to end-stage renal failure [2,6,7]. On the basisof pedigree analysis results, it has been proposed thatERS is an autosomal recessive inheritance disease.AI cases show inherited defects of tooth enamel.While AI cases with autosomal dominant, autosomalrecessive and X-linked inheritance patterns as well assporadic cases of AI have been reported, the pathogen-esis or molecular base of this condition is not yet fullyunderstood [8].Bartter syndrome and nephrogenic diabetes insipi-dus (NDI) are inherited renal tubule disorders and fivetypes of genes responsible for Bartter syndrome(NKCC2, ROMK, CLC-Kb, Barttin and CaSR) andtwo for NDI (V2R for X-linked and AQP2 forautosomal dominant or recessive form) have beenidentified. Bartter syndrome shows hypokalaemicmetabolic alkalosis and, usually, also mild-to-moderate impairment of renal concentration, but itspathophysiology is not fully understood.Here, we present the first reported case of ERScomplicated with Bartter-like syndrome and mildimpaired renal concentration in a child from aconsanguineous family.