Table 1.

Phenotypic characteristics of three individuals with CLDN19 mutation

CharacteristicPatientNormal Values
Age at renal symptoms onset, years100.916
Age at tests, years161316
Organ involvement
    kidneyUTI, NL, NCUTI, NL, NCNC
    eyePM, Strab, nystagmusPMStrab, Myopia, Ir colobomata
    nerveMuscular-exercise intoleranceNoMuscular exercise intolerance
Blood tests
    SCr, μmol/L180200123
    inulin clearance, ml/min per 1.73 m248.8
    eGFR (sMDRD), ml/min per 1.73 m2293053.7
    Mg2+, mmol/L0.590.73 to 1.06
    K+, mmol/L3. to 5
    HCO3, mmol/L23172821 to 30
    Ca2+, mmol/L2.11.842.352.2 to 2.6
    PO43−, mmol/L1.321.740.820.8 to 1.5
    25(OH)vitamin D3, ng/ml13.39 to 45
    1,25(OH)2 vitamin D3, pg/ml6918 to 60
    IPTH, pg/ml15015515 to 85
    alkaline phosphatase, IU/L207656208100 to 280
Urinary tests
    FeMg2+, %a9.9<2%
    Ca2+/Cr ratio, mg/mg0.91.20.9<0.4
    TmPO43−, %83.5>85
    citrate, mg/24 h101285362.4400 to 900
    oxalate, μmol/24 h186163232.8200 to 450
    pH (nocturnal)6.36
    proteinuria, mg/24 h510<300
    hematuria, (0 to 3+)000
    drug intakeCalcium pyridoxineCalcium pyridoxineNo
Renal outcome
    eGFR (sMDRD)ESRD (at age 22)ESRD (at age 16)51 (at age 17)
  • UTI, urinary-tract infection; NL, nephrolithiasis; NC, nephrocalcinosis; SCr, serum creatinine; PM, pigmentary maculopathy; Strab, strabismus; Ir, Iris; sMDRD, standard Modifications of Diet in Renal Disease equation; TmPO43−, maximum rate of renal tubular reabsorption of phosphate.

  • a FeMg2+ was calculated as follows: urinary/plasma [Mg2+]/urinary/plasma [creatinine].