[Liddle syndrome].
In 1963 Liddle et al. described a disorder that simulated primary aldosteronism, characterized by severe hypertension and hypokalemia but with negligible secretion of aldosterone. They theoried that this was a disorder in which the renal tubules transport ions with such abnormal facility that the end result simulates that of a mineralcorticoid excess. Later, it was postulated that this disorder could be related to the abnormality of amiloride sensitive Na channel. The activity of amiloride-sensitive Na channels constitutes the rate limiting step for Na reabsorption in Na transporting epithelia. Recently, the primary sequence of the rat amiloride-sensitive epithelial Na+ channel (rENaC) was determined by functional expression cloning and shown to be composed of three homologous subunits: alpha, beta, and gamma. Its expression of all three subunits in Xenopus oocytes markedly increased the magnitude of these currents. Analysis of subjects with Liddle's syndrome demonstrates the mutation of carboxy-terminal domain in alpha, beta, and gamma subunits. The mutations are either premature termination, frameshift mutation, or missense mutations.
The Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
H
H
Tamura
S
S
Sasaki
D000471:Alkalosis / Q000209:etiology; D000818:Animals; D001483:Base Sequence; D006801:Humans; D006929:Hyperaldosteronism / Q000209:etiology; D006973:Hypertension / Q000209:etiology; D007008:Hypokalemia / Q000209:etiology; D008969:Molecular Sequence Data; D009154:Mutation; D015222:Sodium Channels / Q000235:genetics; D013577:Syndrome
D015222:Sodium Channels