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Maroofian R, Schuele I, Najafi M, Bakey Z, Rad A, Antony D, Habibi H, Schmidts M. Parental Whole-Exome Sequencing Enables Sialidosis Type II Diagnosis due to an NEU1 Missense Mutation as an Underlying Cause of Nephrotic Syndrome in the Child. Kidney Int Rep 2018; 3:1454-1463. [PMID: 30450471 PMCID: PMC6224678 DOI: 10.1016/j.ekir.2018.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 07/16/2018] [Accepted: 07/23/2018] [Indexed: 11/25/2022] Open
Abstract
Introduction Monogenetic renal diseases, including recessively inherited nephrotic syndromes, represent a significant health burden despite being rare conditions. Precise diagnosis, including identification of the underlying molecular cause, is especially difficult in low-income countries and/or if affected individuals are unavailable for biochemical testing. Whole-exome sequencing (WES) has opened up novel diagnostic perspectives for these settings. However, sometimes the DNA of affected individuals is not suitable for WES due to low amounts or degradation. Methods We report on the use of parental WES with implementation of specific stepwise variant filtering to identify the underlying molecular cause of the childhood-onset nephrotic syndrome as nephrosialidosis resulting from a mutation in NEU1. Results Sequencing both parents enabled a nephrosialidosis diagnosis in the deceased child. To date, only 16 other cases of nephrosialidosis have been reported in the literature, with only 1 genetically confirmed case. After we reviewed the clinical information of all reported cases, we found that most patients presented with proteinuria, which started at between 2 and 3 years of age. Renal pathology showed mainly focal segmental glomerulosclerosis (FSGS)with vacuolated cells, and steroid treatment was always unsuccessful. Hepatomegaly was present in nearly all cases, whereas corneal clouding and a cherry red spot on the macula was observed in only approximately 50% of cases. Fourteen of 16 previously reported cases were no longer alive at the time of reporting. Conclusions Our findings demonstrate the power of parental WES to diagnose rare genetic diseases, such as childhood-onset nephrotic syndrome. We further provide a comprehensive overview of the clinical course of nephrosialidosis and raise awareness of this ultra-rare condition as an underlying cause of FSGS.
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Affiliation(s)
- Reza Maroofian
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George's, University of London, London, UK
| | - Isabel Schuele
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University, Faculty of Medicine, Freiburg, Germany
| | - Maryam Najafi
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Zeineb Bakey
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University, Faculty of Medicine, Freiburg, Germany.,Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Abolfazl Rad
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Dinu Antony
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University, Faculty of Medicine, Freiburg, Germany.,Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Haleh Habibi
- Genetic Counselling Center, Hamadan University of Medical Science, Daneshgah-e-Bu Ali Sina, Hamedan, Iran
| | - Miriam Schmidts
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University, Faculty of Medicine, Freiburg, Germany.,Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
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