Table 5.

Genotype/phenotype correlation in FHHNC

GenotypeCL (n = 23)PL (n = 46)P
Age at onset (yr; mean [95% CI])2.2 (1.1 to 3.3)5.6 (3.6 to 7.0)<0.01
Loss of GFR/yr (ml/min per 1.73 m2; mean [95% CI])7.3 (5.0 to 9.6)2.9 (1.8 to 4.3)<0.01
Renal function at end of study<0.01
    GFR >60 ml/min per 1.73 m29% (2/22)54% (25/46)
    GFR <60 ml/min per 1.73 m250% (11/22)20% (9/46)
    ESRD41% (9/22)26% (12/46)
ESRD at 15 yr54% (7/13)20% (6/30)<0.05
ESRD at 20 yr70% (7/10)25% (8/20)NS
Lowest serum Mg (mmol/L; mean [95% CI])0.40 (0.35 to 0.45)0.41 (0.38 to 0.45)NS
Urinary Mg excretion (μ mol/kg per d; mean [95% CI])188 (92 to 283)153 (123 to 183)NS
Lowest serum Ca (mmol/L; mean [95% CI])2.11 (1.96 to 2.27)2.17 (2.1 to 2.25)NS
Urinary Ca excretion (μ mol/kg per d; mean [95% CI])314 (181 to 446)200 (168 to 233)<0.01
Urinary Ca/creatinine (mol/mol; mean [95% CI])2.46 (1.37 to 3.55)1.52 (1.26 to 1.79)<0.05
Intact PTH (pg/ml; mean [95% CI])249 (122 to 376)169 (117 to 220)NS
Follow-up time (yr; mean [95% CI])13.4 (9.2 to 17.6)11.9 (9.2 to 14.7)NS