51. Expanding the Spectrum of FAT1 Nephropathies by Novel Mutations That Affect Hippo Signaling.
- Author
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Fabretti F, Tschernoster N, Erger F, Hedergott A, Buescher AK, Dafinger C, Reusch B, Köntges VK, Kohl S, Bartram MP, Weber LT, Thiele H, Altmueller J, Schermer B, Beck BB, and Habbig S
- Abstract
Introduction: Disease-causing mutations in the protocadherin FAT1 have been recently described both in patients with a glomerulotubular nephropathy and in patients with a syndromic nephropathy., Methods: We identified 4 patients with FAT1 -associated disease, performed clinical and genetic characterization, and compared our findings to the previously published patients. Patient-derived primary urinary epithelial cells were analyzed by quantitative polymerase chain reaction (qPCR) and immunoblotting to identify possible alterations in Hippo signaling., Results: Here we expand the spectrum of FAT1 -associated disease with the identification of novel FAT1 mutations in 4 patients from 3 families (homozygous truncating variants in 3, compound heterozygous missense variants in 1 patient). All patients show an ophthalmologic phenotype together with heterogeneous renal phenotypes ranging from normal renal function to early-onset end-stage kidney failure. Molecular analysis of primary urine-derived urinary renal epithelial cells revealed alterations in the Hippo signaling cascade with a decreased phosphorylation of both the core kinase MST and the downstream effector YAP. Consistently, we found a transcriptional upregulation of bona fide YAP target genes., Conclusion: A comprehensive review of the here identified patients and those previously published indicates a highly diverse phenotype in patients with missense mutations but a more uniform and better recognizable phenotype in the patients with truncating mutations. Altered Hippo signaling and de-repressed YAP activity might be novel contributing factors to the pathomechanism in FAT1 -associated renal disease., (© 2021 International Society of Nephrology. Published by Elsevier Inc.)
- Published
- 2021
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