Kidney Week

Abstract: FR-PO421

Idiopathic Infantile Hypercalcemia in Children With CKD due to Kidney Hypodysplasia

Session Information

• Pediatric Nephrology - I
  November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

• 1800 Pediatric Nephrology

Authors

• Gurevich, Evgenia, Schneider Children's Medical Center of Israel, Petach Tikva, Israel

Evgenia Gurevich,

• Borovitz, Yael, Schneider Children's Medical Center of Israel, Petach Tikva, Israel

Yael Borovitz,

• Levi, Shelly Shlomit, Schneider Children's Medical Center of Israel, Petach Tikva, Israel

Shelly Shlomit Levi,

• Perlman, Sharon, Rabin Medical Center, Petah Tikva, Central, Israel

Sharon Perlman,

• Landau, Daniel, Schneider Children's Medical Center of Israel, Petach Tikva, Israel

Daniel Landau,

Background

Idiopathic infantile hypercalcemia (IIH) etiologies include mutations in CYP24A1, leading to increased 1,25(OH)₂ D, hypercalciuria and suppressed PTH, and in NaPi2, leading to the same metabolic profile via phosphaturia. IIH has not been previously described in CKD due to kidney hypodysplasia (KHD).

Methods

Retrospective study of children with bilateral KHD and simultaneously tested PTH and 1,25(OH)₂D, followed in a tertiary care center between 2015-2021.

Results

Of 295 screened patients, 139 had KHD, 16 (11.5%) of them had IIH (study group), another 26 with normal PTH and any 1,25(OH)₂D served as controls. There were no differences between groups' gender, obstructive uropathy rate and baseline eGFR. Study patients were younger [median (IQR) age: 5.2 (3.2-11.3) vs 61 (13.9 -158.3) months, p<0.001], had higher 1,25(OH)₂D (259.1±91.7 vs 156.5±46.4 pmol/l, p<0.001), total Ca (11.1±0.4 vs 10.7±0.3 mg/dl, p<0.001), and lower phosphate standard deviation score (P-SDS) [median (IQR): -1.4 (-1.9,-0.4) vs -0.3 (-0.8,-0.1) in controls, p=0.03]. During 12 months of follow up, PTH increased among study group (8.8±2.8 to 22.7±12.4 pg/ml, p<0.001), serum calcium decreased (11±0.5 to 10.3±0.6 mg/dl, p=0.004), and 1,25(OH)₂D decreased (259.5±91.7 to 188.2±42.6 pmol/l, p=0.1). P-SDS remained lower in study group vs controls at 12 months [-0.3 (-0.9, 0.4) vs 0.7 (0.6, 0.7), p<0.001]. eGFR did not deteriorate. Five of 9 study group patients with available urine calcium had hypercalciuria. Nephrocalcinosis/lithiasis was found in 5 patients.

Conclusion

Transient IIH was observed in infants with mild CKD due to KHD, in association with relative hypophosphatemia, resembling NaPi2 mutations metabolic profile.