This report describes general characteristics of the group of diseases classified as pseudohypoaldosteronism, type II (PHA2 or PHAII). PHA2 is a genetically heterogeneous disorder, with multiple genes and mapped loci. A comprehensive list of PHA2 subtypes, as defined by OMIM, can be found by following the link in the "OMIM phenotypic series" section, below. For description of work done in flies, see the human disease model report 'pseudohypoaldosteronism, type II, WNK-related' (FBhh0000636).
[updated Sep.2017 by FlyBase; FBrf0222196]
People with Pseudohypoaldosteronism type 2 (PHA2) have high blood pressure (hypertension) and high levels of potassium in their blood (hyperkalemia) despite having normal kidney function. The age of onset of PHA2 is variable and difficult to pinpoint; some affected individuals are diagnosed in infancy or childhood, and others are diagnosed in adulthood. Hyperkalemia usually occurs first, and hypertension develops later in life. Affected individuals also have high levels of chloride (hyperchloremia) and acid (metabolic acidosis) in their blood (together, referred to as hyperchloremic metabolic acidosis). [Genetics Home Reference, pseudohypoaldosteronism type 2; 2017.09.28]
Pseudohypoaldosteronism type II (PHA2) is characterized by hyperkalemia despite normal renal glomerular filtration, hypertension, and correction of physiologic abnormalities by thiazide diuretics. [from MIM:145260; 2017.09.28]
Families with PHA type II due to mutation in the WNK1 gene (PHA2C) are significantly less severely affected than those with mutation in WNK4 (PHA2B) (Boyden, et al., 2012; pubmed:22266938). [from MIM:145260; 2017.09.28]
PHA2 is caused by problems that affect regulation of the amount of sodium and potassium in the body. Sodium and potassium are important in the control of blood pressure, and their regulation occurs primarily in the kidneys. [Genetics Home Reference, pseudohypoaldosteronism type 2; 2017.09.28]
