title: Targeted next-generation sequencing in steroid-resistant nephrotic syndrome: mutations in multiple glomerular genes may influence disease severity.
abstract: Genetic diagnosis of steroid-resistant nephrotic syndrome (SRNS) using Sanger sequencing is complicated by the high genetic heterogeneity and phenotypic variability of this disease. We aimed to improve the genetic diagnosis of SRNS by simultaneously sequencing 26 glomerular genes using massive parallel sequencing and to study whether mutations in multiple genes increase disease severity. High-throughput mutation analysis was performed in 50 SRNS and/or focal segmental glomerulosclerosis (FSGS) patients, a validation cohort of 25 patients with known pathogenic mutations, and a discovery cohort of 25 uncharacterized patients with probable genetic etiology. In the validation cohort, we identified the 42 previously known pathogenic mutations across NPHS1, NPHS2, WT1, TRPC6, and INF2 genes. In the discovery cohort, disease-causing mutations in SRNS/FSGS genes were found in nine patients. We detected three patients with mutations in an SRNS/FSGS gene and COL4A3. Two of them were familial cases and presented a more severe phenotype than family members with mutation in only one gene. In conclusion, our results show that massive parallel sequencing is feasible and robust for genetic diagnosis of SRNS/FSGS. Our results indicate that patients carrying mutations in an SRNS/FSGS gene and also in COL4A3 gene have increased disease severity.
authors.affiliation: 1] Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain [2] Nephrology Department, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Bullich
authors.affiliation: 1] Genomics and Disease Group, Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Catalonia, Spain [2] Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain [3] Hospital del Mar Medical Research Institute (IMIM), Barcelona, Catalonia, Spain [4] CIBER in Epidemiology and Public Health (CIBERESP), Barcelona, Catalonia, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Trujillano
authors.affiliation: Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain.
authors.forename: Sheila
authors.initials: S
authors.lastname: Santín
authors.affiliation: 1] Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain [2] Genomic and Epigenomic Variation in Disease Group, Centre for Genomic Regulation (CRG), Barcelona, Catalonia, Spain.
authors.forename: Stephan
authors.initials: S
authors.lastname: Ossowski
authors.affiliation: Pediatric Nephrology Department, Hospital Universitario La Fe, Valencia, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Mendizábal
authors.affiliation: Pediatric Nephrology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Catalonia, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Fraga
authors.affiliation: Pediatric Nephrology Department, Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Madrid
authors.affiliation: Pediatric Nephrology Department, Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Gema
authors.initials: G
authors.lastname: Ariceta
authors.affiliation: Nephrology Department, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Ballarín
authors.affiliation: Nephrology Department, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain.
authors.forename: Roser
authors.initials: R
authors.lastname: Torra
authors.affiliation: 1] Genomics and Disease Group, Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Catalonia, Spain [2] Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain [3] Hospital del Mar Medical Research Institute (IMIM), Barcelona, Catalonia, Spain [4] CIBER in Epidemiology and Public Health (CIBERESP), Barcelona, Catalonia, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Estivill
authors.affiliation: 1] Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain [2] Nephrology Department, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Catalonia, Spain.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Ars
mesh_terms: D000185:Actinin / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D001324:Autoantigens / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D024141:Collagen Type IV / Q000235:genetics*; D005260:Female; D000080865:Formins; D015870:Gene Expression; D018740:Genetic Heterogeneity; D005838:Genotype; D005923:Glomerulosclerosis, Focal Segmental / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007223:Infant; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D009404:Nephrotic Syndrome / Q000151:congenital* / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D010641:Phenotype; D012720:Severity of Illness Index; D050052:TRPC Cation Channels / Q000235:genetics*; D000074287:TRPC6 Cation Channel
chemical_list: C111453:ACTN4 protein, human; D001324:Autoantigens; D024141:Collagen Type IV; D000080865:Formins; C546959:INF2 protein, human; D008840:Microfilament Proteins; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; C057112:type IV collagen alpha3 chain; D000185:Actinin