Table 1.

Phenotypic characteristics of three individuals with CLDN19 mutation

CharacteristicPatientNormal Values
F1.3F1.4F2.3
GenderFemaleFemaleFemale
Mutationp.Gly20Asp/p.Val44Metp.Gly20Asp/p.Val44Metp.Gly20Asp/p.Gly20Asp
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/L3.53.33.73.5 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].