Table 2.

Molecular variants of CLCNKB and clinical characteristics of patients with Bartter syndromea

PatientEthnic OriginNucleotide ChangebConsequenceExonPolyhydramniosDiagnosisIso/HyposthenuriacHypercalciuriadNephrocalcinosisHypocalciuriaeHypomagnesemiaf
aOnly one potential loss-of-function mutation in CLCNKB was identified. Asterisk indicates one sibling. Abbreviations as in Table 1.
bSequence numbering according to Kieferle et al. (30).
cUrine osmolality ≤300 mosmol/kg.
dUrinary calcium excretion >6 mg/kg per 24 h.
eUrinary calcium excretion <1 mg/kg per 24 h.
fSerum magnesium level <0.65 mmol/L.
Birm3.1His, s1713(AAG>ATG)K560M15-18 mo++---
Birm4.1SAr, s1713(AAG>ATG)K560M15+5 mo++--+
Birm15.1cAm, s1044(TCC>TTC)S337F10+At birth+---+
Birm17.1cAm, s1647(CGC>CCC)R538P14-5 yr-----
Birm19.1cAm, s1752(TTC>TAC)S573Y15+At birth++---
Birm21.1cAm, s263(GCG>ACG)A77T3+At birth-+---
NeckCB.7.1*Fr, f1588ins4bpfs518>X52214-2 wk+----
NeckCB.7.2*Fr, f1588ins4bpfs518>X52214-2 yr+---+
Nijm4Du, s816-2(A>G)Splice acceptor8-1 yr-+--NA
Nijm7Du, s901-1(G>A)Splice acceptor9-1 yrNA---+
Nijm12Du, sdel1423Afs463>X47813-2 yrNA--+NA
All affected individuals4 of 11 (36%)6 of 9 (33%)5 of 11 (45%)0 of 11 (0%)1 of 11 (9%)4 of 9 (44%)
Index cases4 of 10 (40%)5 of 8 (63%)5 of 10 (50%)0 of 10 (0%)1 of 10 (10%)4 of 8 (50%)