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<jats:p>RNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in<jats:italic>DKC1</jats:italic>,<jats:italic>NOP10</jats:italic>, or<jats:italic>NHP2</jats:italic>cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition. Here, we report a phenotype comprising nephrotic syndrome, cataracts, sensorineural deafness, enterocolitis, and early lethality in two pedigrees: males with<jats:italic>DKC1</jats:italic>p.Glu206Lys and two children with homozygous<jats:italic>NOP10</jats:italic>p.Thr16Met. Females with heterozygous<jats:italic>DKC1</jats:italic>p.Glu206Lys developed cataracts and sensorineural deafness, but nephrotic syndrome in only one case of skewed X-inactivation. We found telomere attrition in both pedigrees, but no mucocutaneous abnormalities suggestive of DC. Both mutations fall at the dyskerin–NOP10 binding interface in a region distinct from those implicated in DC, impair the dyskerin–NOP10 interaction, and disrupt the catalytic pseudouridylation site. Accordingly, we found reduced pseudouridine levels in the ribosomal RNA (rRNA) of the patients. Zebrafish<jats:italic>dkc1</jats:italic>mutants recapitulate the human phenotype and show reduced 18S pseudouridylation, ribosomal dysregulation, and a cell-cycle defect in the absence of telomere attrition. We therefore propose that this human disorder is the consequence of defective snoRNP pseudouridylation and ribosomal dysfunction.</jats:p>

Original publication

DOI

10.1073/pnas.2002328117

Type

Journal article

Journal

Proceedings of the National Academy of Sciences

Publisher

Proceedings of the National Academy of Sciences

Publication Date

30/06/2020

Volume

117

Pages

15137 - 15147