An unusual case of hyperkalaemia in infancy: answer
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : Mireille Formosa & Nicholas J. Webb & Mohan Shenoy
- چاپ و سال / کشور: 2011
Description
PHA type II is a rare but interesting disorder because of the unusual association of hypertension with hyperkalemia which appears to indicate a disassociation of the two primary functions of aldosterone—salt reabsorption and potassium secretion [5]. Serum aldosterone levels in this condition can vary widely and has led to some clinicians questioning the utility of the term pseudohypoaldosteronism to describe the condition. The molecular genetic discovery of the mutations in WNK1 and WNK4 which cause PHA type II has provided an insight into the complex mechanism by which the kidney regulates the balance between salt reabsorption and potassium secretion. There is an emerging consensus that PHA type II associated with WNK4 is due to an inactivating mutation leading to a gain of function of NCC and, consequently, increased sodium reabsorption in the distal convoluted tubule [3]. The detection of marked hypercalciuria seen in these patients also supports this hypothesis. WNK1-associated PHA type II, however, appears to be due to an intronic mutation, leading to overexpression of the gene product. The absence of WNK1 and WNK4 in many PHA type II kindreds suggests that there must be one or more as yet unidentified PHA type II genes. In terms of clinical management, children with PHA type II will require long-term thiazide diuretics in addition to a low salt diet.
Pediatr Nephrol (2011) 26:1067–1069 DOI 10.1007/s00467-010-1684-x Received: 7 June 2010 / Revised: 10 September 2010 / Accepted: 24 September 2010 / Published online: 5 November 2010
