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Abstract: SA-PO297

Characterization of Nephrocalcinosis Phenotypes at Pediatric or Adulthood Ages of Onset

Session Information

Category: Bone and Mineral Metabolism

  • 502 Bone and Mineral Metabolism: Clinical

Authors

  • Milhomem, Elenice Andrade, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Matos, Ana Cristina, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Vaisbich, Maria H, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Heilberg, Ita Pfeferman, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
Background

This study aimed to compare the clinical and laboratorial presentation and etiology of Nephrocalcinosis (NC) at different ages of onset.

Methods

A retrospective study was conducted based on clinical and laboratorial data from medical records of outpatients aged < or ≥ 18 years old with radiologic evidence of renal parenchymal calcifications by computed tomography or renal ultrasound suggesting NC at presentation.

Results

A total of 81 patients, divided into 2 groups, 56 adults (44 F/12M, ≥18 yrs) and 25 pediatric (14F/11M, <18 yrs), were included. Pediatric patients were referred mostly because of hydroelectrolytic/metabolic disorders as the primary presentation of NC (84 vs 30%, p< 0.01), history of failure to thrive (48 vs 3%, p< 0,001) and deafness (28 vs 5%, p< 0,01), against higher association of NC with nephrolithiasis and more urological procedures in adults (70 vs 40%, p < 0.001 & 45 vs 24%, p= 0.056, respectively). Mean estimated glomerular filtration (eGFR) rate was lower in adults (88 ± 31 vs 108 ± 21 mL/min/1.73m2, p< 0.01). Molecular diagnosis could be established in 17/19 genetically tested cases corresponding to 21% of the whole sample. The individual distribution of underlying causes of NC per age are shown in the Figure. Distal renal tubular acidosis (dRTA) and monogenic hypercalciuria were statistically more frequent in the pediatric group (40 vs 13 % and 24 vs 11 % , p= 0.001, respectively) and primary hyperparathyroidism (HPT) and use of drugs were seen only in adults (14 and 7%). Undetermined or still under investigation cases were more common among adults. Cases of familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC), medullary sponge kidney (MSK), Lowe, Dent, Hypoparathyroidism (HypoPT) did not differ.

Conclusion

Adults with nephrocalcinosis exhibited reduced renal function at presentation possibly due to delay on diagnosis, worse clinical outcome or previous urological procedures. Molecular analysis could help to further elucidate clinical causes of NC in this group.