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Abstract: PO0572

Childhood Hypercalciuric Hypercalcemia with Elevated Vitamin D and Suppressed Parathyroid Hormone: Long-Term Follow-Up

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Gurevich, Evgenia, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
  • Levi, Shelly Shlomit, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
  • Borovitz, Yael, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
  • Alfandary, Hadas, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
  • Ganon, Liat, Department of Nephrology and Hypertension, the Chaim Sheba Medical Center, Tel-Hashomer, Israel, Tel Aviv, Israel
  • Dinour, Dganit, Department of Nephrology and Hypertension, the Chaim Sheba Medical Center, Tel-Hashomer, Israel, Tel Aviv, Israel
  • Davidovits, Miriam, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
Background

Hypercalcemia with low parathyroid hormone (PTH) level, hypercalciuria, nephrocalcinosis, or nephrolithiasis, was recently reported as caused by mutations in CYP24A1 and SLC34A genes. These encode for vitamin D-24A-hydroxylase and for the renal phosphate transporters NaPiIIa and NaPiIIc, respectively. We aimed to describe the course of these conditions during long-term follow-up

Methods

Ten patients with the above features were followed in our center during 1998-2019. Relevant laboratory and imaging data and results of genetic evaluation were retrieved from medical files

Results

The median age at presentation was 9.5 months (range 1 month-11 years), six were males, and the median follow-up time was 3.8 (1.1-14) years. Mutations in CYP24A1 and SLC34A3 were identified in three and one patients, respectively. Five patients presented with nephrocalcinosis, three with nephrolithiasis, and two had normal renal ultrasound. High blood calcium and 1,25-(OH)2D levels at presentation decreased during follow-up (11.1±1 vs 9.9±0.5 mg\dl (p=0.012), and 307±130 vs 209±65 pmol\l (p=0.03), respectively); this paralleled an increase in suppressed PTH levels (5.8±0.9 vs 11.8±7.3 pg\ml, p=0.2). Substantial improvements in hypercalciuria and renal sonography findings were not observed. Two patients had impaired renal function (eGFR 84-88 ml\min\1/73m2) at the last follow up. Interventions included appropriate diet, citrate supplementation, and thiazides

Conclusion

In patients with the described clinical and laboratory profile, abnormal renal sonographic findings can persist despite appropriate treatment; and renal function may deteriorate. Long-term follow up and intervention to prevent nephrocalcinosis and nephrolithiasis are recommended in these children