Referenced in: none

Automatically associated channels: Kir3.4

Title: Expression and mutations of KCNJ5 mRNA in Japanese patients with aldosterone-producing adenomas.

Authors: Ryo Taguchi, Masanobu Yamada, Yasuyo Nakajima, Tetsurou Satoh, Koshi Hashimoto, Nobuyuki Shibusawa, Atsushi Ozawa, Shuichi Okada, Nana Rokutanda, Daisuke Takata, Yukio Koibuchi, Jun Horiguchi, Tetsunari Oyama, Izumi Takeyoshi, Masatomo Mori

Journal, date & volume: J. Clin. Endocrinol. Metab., 2012 Apr , 97, 1311-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22278422

Abstract
Mutations of the KCNJ5 gene have recently been identified in patients with aldosterone-producing adenomas (APA).Our objective was to investigate the expression and mutations of the KCNJ5 gene in Japanese patients with APA.We sequenced KCNJ5 cDNA and measured KCNJ5 mRNA levels in 23 patients with APA operated on at Gunma University Hospital.Mutations and mRNA levels of the KCNJ5 gene were examined and compared to those in cortisol-producing adenomas (Cushing's syndrome) and pheochromocytomas.Of the 23 patients with APA, 15 (65.2%) had two somatic mutations of the KCNJ5 gene: 12 cases of p.G151R (eight with c.451G>A, and four with c.451G>C) and three cases of p.L168R (c.503T>G). Levels of KCNJ5 mRNA were significantly higher in the APA with mutations than those without. Immunohistochemistry also showed a stronger staining of KCNJ5 on the cell membrane in the tumor with a mutation. Furthermore, a PCR-restriction fragment length polymorphism assay with c.503T>G revealed the mutant mRNA to be expressed at a similar level to the wild type. The level of KCNJ5 mRNA in cortisol-producing adenomas was approximately 30% of that in APA, and almost no expression was observed in pheochromocytomas.We found that: 1) a significant number of patients with APA had somatic mutations of the KCNJ5 gene; 2) KCNJ5 mRNA levels were higher in the APA with KCNJ5 mutations; and 3) the expression of KCNJ5 mRNA was significantly higher in APA than cortisol-producing adenomas and pheochromocytomas.