title: Accentuated hyperparathyroidism in type II Bartter syndrome.
abstract: Bartter syndrome (BS) may be associated with different degrees of hypercalciuria, but marked parathyroid hormone (PTH) abnormalities have not been described.
  
  
  
  We compared clinical and laboratory data of patients with either ROMK-deficient type II BS (n = 14) or Barttin-deficient type IV BS (n = 20).
  
  
  
  Only BS-IV patients remained mildly hypokalemic in spite of a higher need for potassium supplementation. Estimated glomerular filtration rate (eGFR) was mildly decreased in only four BS-IV patients. Average PTH values were significantly higher in BS-II (160.6 ± 85.8 vs. 92.5 ± 48 pg/ml in BS-IV, p = 0.006). In both groups, there was a positive correlation between age and log(PTH). Levels of 25(OH) vitamin D were not different. Total serum calcium was lower (within normal limits) and age-related serum phosphate (Pi)-SDS was increased in BS-II (1.19 ± 0.71 vs. 0.01 ± 1.04 in BS-IV, p < 0.001). The GFR threshold for Pi reabsorption was higher in BS-II (5.63 ± 1.25 vs. 4.36 ± 0.98, p = 0.002). Spot urine calcium/creatinine ratio and nephrocalcinosis rate (100 vs. 16 %) were higher in the BS-II group.
  
  
  
  PTH, serum Pi levels, and urinary threshold for Pi reabsorption are significantly elevated in type II vs. type IV BS, suggesting a PTH resistance state. This may be a response to more severe long-standing hypercalciuria, leading to a higher rate of nephrocalcinosis in BS-II.
authors: Department of Pediatrics B, Schneider Children's Medical Center of Israel, 14 Kaplan Street, Petach Tikva, 49202, Israel. ldaniel@bgu.ac.il.|Ben Gurion University of the Negev, Beer Sheva, Israel. ldaniel@bgu.ac.il.
authors: Daniel
authors: 0000-0001-6347-7891
authors: D
authors: Landau
authors: Ben Gurion University of the Negev, Beer Sheva, Israel.|Division of Pediatrics, Soroka University Medical Center, Beer Sheva, Israel.
authors: Evgenia
authors: E
authors: Gurevich
authors: Department of Pediatrics, Kaplan Medical Center, Rehovot, Israel.
authors: Levana
authors: L
authors: Sinai-Treiman
authors: Ben Gurion University of the Negev, Beer Sheva, Israel.|Division of Pediatrics, Soroka University Medical Center, Beer Sheva, Israel.
authors: Hannah
authors: H
authors: Shalev
mesh_terms: D000293:Adolescent; D001477:Bartter Syndrome / Q000150:complications*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000209:etiology*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone
keywords: Bartter syndrome; Barttin; Hypercalciuria; Nephrocalcinosis; Parathyroid hormone; ROMK