Background Hereditary cystic kidney diseases such as nephronophthisis, polycystic kidney disease and Bardet-Biedl syndrome (BBS) are caused by a dysfunction of primary cilia. Cilia are involved in a variety of cellular functions and perceptions, with one of them being the sense of smell. Hyposmia is a typical feature found in patients with BBS. However, reports of olfactory dysfunction in other cystic kidney diseases are sparse. Here we provide a systematic survey on olfaction in a large cohort of patients displaying genetically determined renal ciliopathies.
Methods We performed a match-controlled systematic olfactory evaluation in a group of 75 patients with a defined genetic background using age adapted and validated odour identification tests.
Results Test results revealed a significant olfactory deficit in patients carrying TMEM67 variants (n=4), while all other genetic disorders causing nephronophthisis (n=25) or polycystic kidney disease (n=18) were not associated with an impaired sense of smell. Also in patients with BBS, olfactory performance was depending on the underlying molecular defect. While defects in the BBS1 gene (n=9) had no impact on the sense of smell, all other BBS gene disorders (n=19) were associated with significant hyposmia. Noteworthy, there was no correlation of the olfactory deficit with the level of renal impairment.
Conclusion Hyposmia is a part of the clinical spectrum of BBS and of other renal ciliopathies. Depending on the genetic background, clinicians should be aware of this subtle and so far underappreciated symptom when clinically assessing patients with BBS or TMEM67 gene variants.
- congenital, hereditary, and neonatal diseases and abnormalities
- genetic predisposition to disease
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Contributors Mareike Dahmer-Heath, Petra Pennekamp, Martin Konrad, Valentin Schriever, Jens König: Conceptualization of the study.
Valentin Schriever: Provision of U-Sniff tests and healthy control cohort data.
Sabine Kollmann, Mareike Dahmer-Heath, Carolin Schleithoff, Andrea Titieni, Metin Cetiner, Jens König: Investigation.
Mareike Dahmer-Heath, Carolin Schleithoff, Jens König: Data curation.
Joachim Gerß: Formal analysis.
Mareike Dahmer-Heath, Jens König: Writing- Original draft preparation.
Petra Pennekamp, Martin Konrad, Burkhard Tönshoff, Matthias Hansen, Ludwig Patzer: Writing - Review & Editing
Jens König, Martin Konrad: Supervision
Jens König, Martin Konrad: Funding acquisition
Funding This study was part of the NEOCYST consortium funded by the German Federal Ministry of Research and Education (BMBF, grant 01GM1903A).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the local ethics committee. Informed consent was obtained from all participants and/or parents/legal guardians when appropriate. This study was conducted as part of the Network for Early Onset of Cystic Kidney Disecystic kidney diseases (NEOCYST) registry in accordance with the Declaration of Helsinki on Biomedical Studies Involving Human Subjects.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. Additional clinical and genetic data are available on request from the NEOCYST clinical database (www.neocyst.de)
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