Mucin-1 kidney disease, previously described as medullary cystic kidney disease type 1 (MCKD1, OMIM 174000), is an autosomal dominant tubulointerstitial kidney disease recently shown to be caused by a single-base insertion within the variable number tandem repeat region of the MUC1 gene. Because of variable age of disease onset and often subtle signs and symptoms, clinical diagnosis of mucin-1 kidney disease and differentiation from other forms of hereditary kidney disease have been difficult. The causal insertion resides in a variable number tandem repeat region with high GC content, which has made detection by standard next-generation sequencing impossible to date. The inherently difficult nature of this mutation required an alternative method for routine detection and clinical diagnosis of the disease. We therefore developed and validated a mass spectrometry-based probe extension assay with a series of internal controls to detect the insertion event using 24 previously characterized positive samples from patients with mucin-1 kidney disease and 24 control samples known to be wild type for the variant. Validation results indicate an accurate and reliable test for clinically establishing the molecular diagnosis of mucin-1 kidney disease with 100% sensitivity and specificity across 275 tests called.

• MeSH
• diagnostické techniky molekulární * MeSH
• genotyp MeSH
• hmotnostní spektrometrie metody   normy   MeSH
• lidé MeSH
• mucin 1 genetika   MeSH
• mutace * MeSH
• polycystické ledviny autozomálně dominantní diagnóza   genetika   MeSH
• průběh práce MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Intracellular accumulation of misfolded proteins causes toxic proteinopathies, diseases without targeted therapies. Mucin 1 kidney disease (MKD) results from a frameshift mutation in the MUC1 gene (MUC1-fs). Here, we show that MKD is a toxic proteinopathy. Intracellular MUC1-fs accumulation activated the ATF6 unfolded protein response (UPR) branch. We identified BRD4780, a small molecule that clears MUC1-fs from patient cells, from kidneys of knockin mice and from patient kidney organoids. MUC1-fs is trapped in TMED9 cargo receptor-containing vesicles of the early secretory pathway. BRD4780 binds TMED9, releases MUC1-fs, and re-routes it for lysosomal degradation, an effect phenocopied by TMED9 deletion. Our findings reveal BRD4780 as a promising lead for the treatment of MKD and other toxic proteinopathies. Generally, we elucidate a novel mechanism for the entrapment of misfolded proteins by cargo receptors and a strategy for their release and anterograde trafficking to the lysosome.

• MeSH
• benzamidy chemie   metabolismus   farmakologie   MeSH
• epitelové buňky cytologie   metabolismus   MeSH
• imidazolinové receptory antagonisté a inhibitory   genetika   metabolismus   MeSH
• indukované pluripotentní kmenové buňky cytologie   metabolismus   MeSH
• ledviny cytologie   metabolismus   patologie   MeSH
• lidé MeSH
• lyzozomy metabolismus   MeSH
• malá interferující RNA metabolismus   MeSH
• mucin 1 chemie   genetika   metabolismus   MeSH
• myši transgenní MeSH
• myši MeSH
• nemoci ledvin metabolismus   patologie   MeSH
• posunová mutace MeSH
• RNA interference MeSH
• signální dráha UPR účinky léků   MeSH
• transkripční faktor ATF6 metabolismus   MeSH
• vezikulární transportní proteiny chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Although genetic lesions responsible for some mendelian disorders can be rapidly discovered through massively parallel sequencing of whole genomes or exomes, not all diseases readily yield to such efforts. We describe the illustrative case of the simple mendelian disorder medullary cystic kidney disease type 1 (MCKD1), mapped more than a decade ago to a 2-Mb region on chromosome 1. Ultimately, only by cloning, capillary sequencing and de novo assembly did we find that each of six families with MCKD1 harbors an equivalent but apparently independently arising mutation in sequence markedly under-represented in massively parallel sequencing data: the insertion of a single cytosine in one copy (but a different copy in each family) of the repeat unit comprising the extremely long (~1.5-5 kb), GC-rich (>80%) coding variable-number tandem repeat (VNTR) sequence in the MUC1 gene encoding mucin 1. These results provide a cautionary tale about the challenges in identifying the genes responsible for mendelian, let alone more complex, disorders through massively parallel sequencing.

• MeSH
• cytosin metabolismus   MeSH
• genetická vazba MeSH
• haplotypy MeSH
• lidé MeSH
• minisatelitní repetice * genetika   MeSH
• mucin 1 * genetika   metabolismus   MeSH
• mutace * MeSH
• polycystické ledviny autozomálně dominantní * MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH