Poor phenotype-genotype association in a large series of patients with Type III Bartter syndrome
García-Castaño, Alejandro (Instituto de Investigación Sanitaria Biocruces Bizkaia)
Pérez de Nanclares, Gustavo (Instituto de Investigación Sanitaria Biocruces Bizkaia)
Madariaga, Leire (Universidad del País Vasco. Departamento de Pediatría)
Aguirre, Mireia (Hospital Universitario de Cruces (Barakaldo, País Basc))
Madrid, Alvaro (Hospital Universitari Vall d'Hebron)
Chocron, Sara (Hospital Universitari Vall d'Hebron)
Nadal, Inmaculada (Hospital Virgen del Camino (Pamplona))
Navarro, Mercedes (Hospital Universitario La Paz (Madrid))
Lucas, Elena (Hospital de Manises (València))
Fijo, Julia (Hospital Universitario Virgen del Rocío (Sevilla, Andalusia))
Espino, Mar (Hospital Universitario Fundación Alcorcón)
Espitaletta, Zilac (Hospital Universitario San Ignacio, Bogotá)
García Nieto, Víctor (Hospital Universitario Nuestra Señora de Candelaria (Santa Cruz de Tenerife))
Barajas de Frutos, David (Hospital Universitario Virgen de las Nieves (Granada))
Loza, Reyner (Hospital Cayetano Heredia, Lima)
Pintos, Guillem (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol)
Castaño, Luis (Instituto de Investigación Sanitaria Biocruces Bizkaia)
Ariceta Iraola, Gema (Hospital Universitari Vall d'Hebron)
Grupo RenalTube
Universitat Autònoma de Barcelona

Date:	2017
Abstract:	Type III Bartter syndrome (BS) is an autosomal recessive renal tubule disorder caused by loss-of-function mutations in the CLCNKB gene, which encodes the chloride channel protein ClC-Kb. In this study, we carried out a complete clinical and genetic characterization in a cohort of 30 patients, one of the largest series described. By comparing with other published populations, and considering that 80% of our patients presented the p. Ala204Thr Spanish founder mutation presumably associated with a common phenotype, we aimed to test the hypothesis that allelic differences could explain the wide phenotypic variability observed in patients with type III BS. Methods. Clinical data were retrieved from the referral centers. The exon regions and flanking intronic sequences of the CLCNKB gene were screened for mutations by polymerase chain reaction (PCR) followed by direct Sanger sequencing. Presence of gross deletions or duplications in the region was checked for by MLPA and QMPSF analyses. Results. Polyuria, polydipsia and dehydration were the main common symptoms. Metabolic alkalosis and hypokalemia of renal origin were detected in all patients at diagnosis. Calciuria levels were variable: hypercalciuria was detected in 31% of patients, while 23% had hypocalciuria. Nephrocalcinosis was diagnosed in 20% of the cohort. Two novel CLCNKB mutations were identified: a small homozygous deletion (c. 753delG) in one patient and a small deletion (c. 1026delC) in another. The latter was present in compound heterozygosis with the already previously described p. Glu442Gly mutation. No phenotypic association was obtained regarding the genotype. Conclusion. A poor correlation was found between a specific type of mutation in the CLCNKB gene and type III BS phenotype. Importantly, two CLCNKB mutations not previously described were found in our cohort.
Grants:	Instituto de Salud Carlos III FIS/PI09/90888 Instituto de Salud Carlos III FIS/PI11/01412
Note:	Altres ajuts: Departamento de Salud del Gobierno Vasco (2014111064) i Departamento de Educación del Gobierno Vasco (IT795-13)
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	PloS one, Vol. 12 Núm. 3 (2017) , p. 1-11, ISSN 1932-6203

DOI: 10.1371/journal.pone.0173581
PMID: 28288174

11 p, 788.9 KB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Health sciences and biosciences > Institut d'Investigació en Ciencies de la Salut Germans Trias i Pujol (IGTP)
Articles > Research articles
Articles > Published articles