Adult presentation of Bartter syndrome type IV with erythrocytosis

Heilberg, Ita Pfeferman; Tótoli, Cláudia; Calado, Joaquim

doi:10.1590/s1679-45082015rc3013

Cited by 17 publications

(13 citation statements)

References 13 publications

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“…3d–l ). In Bartter syndrome, in which NKCC2 is mutated, patients with erythrocytosis were reported 22 , 23 . Elevated hematocrit levels in Bartter syndrome might be caused not only by hemoconcentration but by elevated EPO production.…”

Section: Discussionmentioning

confidence: 99%

Tubular immaturity causes erythropoietin-deficiency anemia of prematurity in preterm neonates

Asada

2018

Sci Rep

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Kidneys are physiologically hypoxic due to huge oxygen consumption for tubular reabsorption. The physiological hypoxia makes the kidney an appropriate organ for sensitively detecting oxygen levels and producing erythropoietin (EPO). In preterm neonates, immature kidneys cannot produce sufficient EPO, which results in anemia of prematurity (AOP). The cause of EPO insufficiency in AOP has been unclear, therefore current therapeutic options are transfusion and injection of recombinant human EPO. This report shows that the cause of insufficient EPO production in AOP is elevated renal oxygen levels due to poor oxygen consumption by immature tubules. Neonatal mice with AOP showed low tubular transporter expression and elevated renal oxygen levels compared with those without AOP. Enhancing transporter expression in AOP mice induced renal hypoxia and EPO production. In preterm neonates, red blood cell counts, hemoglobin levels, and hematocrit levels correlated with tubular function, but not with serum creatinine, gestational age, or birth weight. Furthermore, pharmacological upregulation of hypoxia signaling ameliorated AOP in mice. These data suggest that tubular maturation with increased oxygen consumption is required for renal EPO production.

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Section: Discussionmentioning

confidence: 99%

Tubular immaturity causes erythropoietin-deficiency anemia of prematurity in preterm neonates

Asada

2018

Sci Rep

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“…48 Rare unrelated cases due to this G47R mutation, responsible for such forms of late onset of type IV, have been described in Brazil, Portugal, Japan, and Spain. [49][50][51][52] The sensory function of the inner ear becomes impaired in type IVa and IVb BS. In type IVa, barttin mutations impair potassium secretion in the stria vascularis and the vestibular labyrinth, whereas in type IVb mutations they occur in both chloride channels impairing their normal function in the inner ear.…”

Section: Type Iva and Ivb Bsmentioning

confidence: 99%

Bartter syndrome: causes, diagnosis, and treatment

Cunha¹,

Heilberg²

2018

IJNRD

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Bartter syndrome is an inherited renal tubular disorder caused by a defective salt reabsorption in the thick ascending limb of loop of Henle, resulting in salt wasting, hypokalemia, and metabolic alkalosis. Mutations of several genes encoding the transporters and channels involved in salt reabsorption in the thick ascending limb cause different types of Bartter syndrome. A poor phenotype–genotype relationship due to the interaction with other cotransporters and different degrees of compensation through alternative pathways is currently reported. However, phenotypic identification still remains the first step to guide the suspicion of Bartter syndrome. Given the rarity of the syndrome, and the lack of genetic characterization in most cases, limited clinical evidence for treatment is available and the therapy is based mainly on the comprehension of renal physiology and relies on the physician’s personal experiences. A better understanding of the mutated channels and transporters could possibly generate targets for specific treatment in the future, also encompassing drugs aiming to correct deficiencies in folding or plasma membrane expression of the mutated proteins.

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“…4,38 Yet, there is a wide spectrum of severity in all forms of BS: some patients with BS type 1, 2, or 4 present only later in life, including adulthood, whereas some patients with BS type 3 have a severe antenatal presentation with prematurity as early as 22 weeks of gestation and polyhydramnios treated with amniocentesis. [39][40][41][42][43] There are some data for CLCNKB suggesting that mutation type may influence the phenotype, with mutations affecting the Barttin-binding site, the dimerization interface, or the selectivity filter causing more severe dysfunction. 44 Yet, the most common mutation in CLCNKB is a whole-gene deletion, which can be associated with the whole phenotypic spectrum.…”

Section: Thick Ascending Limbmentioning

confidence: 99%

Salt-Losing Tubulopathies in Children: What’s New, What’s Controversial?

Kleta

Böckenhauer

2017

JASN

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Renal tubulopathies provide insights into the inner workings of the kidney, yet also pose therapeutic challenges. Because of the central nature of sodium in tubular transport physiology, disorders of sodium handling may affect virtually all aspects of the homeostatic functions of the kidney. Yet, owing to the rarity of these disorders, little clinical evidence regarding treatment exists. Consequently, treatment can vary widely between individual physicians and centers and is based mainly on understanding of renal physiology, reported clinical observations, and individual experiences. Salt-losing tubulopathies can affect all tubular segments, from the proximal tubule to the collecting duct. But the more frequently observed disorders are Bartter and Gitelman syndrome, which affect salt transport in the thick ascending limb of Henle's loop and/or the distal convoluted tubule, and these disorders generate the greatest controversies regarding management. Here, we review clinical and molecular aspects of salt-losing tubulopathies and discuss novel insights provided mainly by genetic investigations and retrospective clinical reviews. Additionally, we discuss controversial topics in the management of these disorders to highlight areas of importance for future clinical trials. International collaboration will be required to perform clinical studies to inform the treatment of these rare disorders.

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Adult presentation of Bartter syndrome type IV with erythrocytosis

Cited by 17 publications

References 13 publications

Tubular immaturity causes erythropoietin-deficiency anemia of prematurity in preterm neonates

Tubular immaturity causes erythropoietin-deficiency anemia of prematurity in preterm neonates

Bartter syndrome: causes, diagnosis, and treatment

Salt-Losing Tubulopathies in Children: What’s New, What’s Controversial?

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