Three novel missense mutations of WNK4, a kinase mutated in inherited hypertension, in Japanese hypertensives: implication of clinical phenotypes.
BACKGROUND
Mutations in serine-threonine kinase WNK4 with no lysine (K) at a key catalytic residue cause familial hypertension known as pseudohypoaldosteronism type II (PHAII). The objective of this study was to test whether more subtle changes of WNK4 could be implicated in hypertension or renal failure.


METHODS
We screened 956 Japanese patients with hypertension or renal failure for mutations in exons 7 and 17 in the WNK4 gene where the mutations were identified in patients with PHAII.


RESULTS
We identified three novel missense mutations, Met546Val (n = 2) and Pro556Thr (n = 2) in exon 7, and Pro1173Thr (n = 1) in exon 17, in a heterozygous state in addition to four single nucleotide polymorphisms including one synonymous mutation (Ala547Ala). Results of genotyping Met546Val and Pro556Thr mutations indicated that these mutations were not present in a Japanese general population (n = 1875).


CONCLUSIONS
The present study indicated that a systematic screening of WNK4 in a large set of patients with hypertension or renal failure detected some rare genetic variants. Although substantial contribution of three novel missense mutations in exons 7 and 17 of WNK4 to the genetics of hypertension or renal failure is still unclear, these mutations in the WNK4 gene identified in Japanese hypertensives but not in a general population may contribute to hypertension and progression of hypertensive complications to some extent.
Kamide
Kei
K
Division of Hypertension and Nephrology, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan. kamide@hsp.ncvc.go.jp
Takiuchi
Shin
S
Tanaka
Chihiro
C
Miwa
Yoshikazu
Y
Yoshii
Masayoshi
M
Horio
Takeshi
T
Mannami
Toshifumi
T
Kokubo
Yoshihiro
Y
Tomoike
Hitonobu
H
Kawano
Yuhei
Y
Miyata
Toshiyuki
T
D000368:Aged; D019943:Amino Acid Substitution / Q000235:genetics; D016022:Case-Control Studies; D005091:Exons / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000235:genetics*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D011546:Pseudohypoaldosteronism / Q000453:epidemiology / Q000235:genetics
D017346:Protein Serine-Threonine Kinases; C433806:WNK4 protein, human