title: A novel frameshift mutation in NR3C2 leads to decreased expression of mineralocorticoid receptor: a family with renal pseudohypoaldosteronism type 1.
abstract: Pseudohypoaldosteronism type 1 (PHA1) is a rare genetic disease characterized by resistance to aldosterone, and the renal form of PHA1 is associated with heterozygous inactivating mutations in NR3C2, which encodes mineralocorticoid receptor (MR). Here we report a case of renal PHA1 due to a novel frameshift mutation in NR3C2. A 10-day-old Japanese male infant, born at 39 weeks gestation (birth weight, 2,946 g), was admitted to our hospital because of lethargy and vomiting, with a 6.7% weight loss since birth. Laboratory test results were: Na+, 132 mEq/L; K+, 6.6 mEq/L; Cl+, 93 mEq/L. Both plasma aldosterone level and plasma renin activity were markedly elevated at diagnosis, 2,940 ng/dL (normal range: 26.9-75.8 ng/dL) and 560 ng/mL/h (normal range 3.66-12.05 ng/mL/h), respectively. Direct sequence analysis of NR3C2 revealed a novel heterozygous mutation (c.3252delC) in the patient and his father. The mutation causes a frameshift starting at amino acid I 963 within the C terminal ligand-binding domain of MR and results in a putative abnormal stop codon at amino acid 994, with an extension of 10 amino acids compared to normal MR. We performed cell culture experiments to determine the levels of mutant NR3C2 mRNA and MR, and evaluate the effects of the mutation on MR response to aldosterone. The mutation decreased the expression of MR, but not NR3C2 mRNA, and led to decreased MR function, with no dominant negative effect. These results provide important information about MR function and NR3C2 mutation in PHA1.
authors.affiliation: Division of Pediatrics & Perinatology, Tottori University Faculty of Medicine, Yonago 683-8504, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kawashima Sonoyama
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tajima
authors.forename: Masanobu
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Akiko
authors.initials: A
authors.lastname: Hasegawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Miyahara
authors.forename: Rei
authors.initials: R
authors.lastname: Nishimura
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hashida
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hayashi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hanaki
authors.forename: Susumu
authors.initials: S
authors.lastname: Kanzaki
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D015536:Down-Regulation / Q000235:genetics; D005190:Family; D016368:Frameshift Mutation; D006801:Humans; D007231:Infant, Newborn; D007564:Japan; D008297:Male; D011546:Pseudohypoaldosteronism / Q000235:genetics* / Q000378:metabolism; D018161:Receptors, Mineralocorticoid / Q000235:genetics* / Q000378:metabolism*
chemical_list: C561839:NR3C2 protein, human; D018161:Receptors, Mineralocorticoid