A New Multisystem Disorder Caused by the Gαs Mutation p.F376V.
J Clin Endocrinol Metab
; 104(4): 1079-1089, 2019 04 01.
Article
em En
| MEDLINE
| ID: mdl-30312418
ABSTRACT
CONTEXT The α subunit of the stimulatory G protein (Gαs) links numerous receptors to adenylyl cyclase. Gαs, encoded by GNAS, is expressed predominantly from the maternal allele in certain tissues. Thus, maternal heterozygous loss-of-function mutations cause hormonal resistance, as in pseudohypoparathyroidism type Ia, whereas somatic gain-of-function mutations cause hormone-independent endocrine stimulation, as in McCune-Albright syndrome. OBJECTIVE:
We report two unrelated boys presenting with a new combination of clinical findings that suggest both gain and loss of Gαs function. DESIGN ANDSETTING:
Clinical features were studied and sequencing of GNAS was performed. Signaling capacities of wild-type and mutant Gαs were determined in the presence of different G protein-coupled receptors (GPCRs) under basal and agonist-stimulated conditions.RESULTS:
Both unrelated patients presented with unexplained hyponatremia in infancy, followed by severe early onset gonadotrophin-independent precocious puberty and skeletal abnormalities. An identical heterozygous de novo variant (c.1136T>G; p.F376V) was found on the maternal GNAS allele in both patients; this resulted in a clinical phenotype that differed from known Gαs-related diseases and suggested gain of function at the vasopressin 2 receptor (V2R) and lutropin/choriogonadotropin receptor (LHCGR), yet increased serum PTH concentrations indicative of impaired proximal tubular PTH1 receptor (PTH1R) function. In vitro studies demonstrated that Gαs-F376V enhanced ligand-independent signaling at the PTH1R, LHCGR, and V2R and, at the same time, blunted ligand-dependent responses. Structural homology modeling suggested mutation-induced modifications at the C-terminal α5 helix of Gαs that are relevant for interaction with GPCRs and signal transduction.CONCLUSIONS:
The Gαs p.F376V mutation causes a previously unrecognized multisystem disorder.
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Base de dados:
MEDLINE
Assunto principal:
Puberdade Precoce
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Osso e Ossos
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Cromograninas
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Subunidades alfa Gs de Proteínas de Ligação ao GTP
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Hiponatremia
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Alemanha