A DNA repair disorder caused by de novo monoallelic DDB1 variants is associated with a neurodevelopmental syndrome.

TitleA DNA repair disorder caused by de novo monoallelic DDB1 variants is associated with a neurodevelopmental syndrome.
Publication TypeJournal Article
Year of Publication2021
AuthorsWhite, SM, Bhoj, E, Nellaker, C, Lachmeijer, AMA, Marshall, AE, Boycott, KM, Li, D, Smith, W, Hartley, T, McBride, A, Ernst, ME, May, AS, Wieczorek, D, Jamra, RAbou, Koch-Hogrebe, M, Õunap, K, Pajusalu, S, van Gassen, KLI, Sadedin, S, Ellingwood, S, Tan, TYang, Christodoulou, J, Barea, J, Lockhart, PJ, Nezarati, MM, Kernohan, KD
Corporate AuthorsCare4Rare Canada Consortium
JournalAm J Hum Genet
Date Published2021 04 01
KeywordsAdolescent, Alleles, Child, Child, Preschool, DNA Repair, DNA-Binding Proteins, Female, Humans, Male, Mutation, Neurodevelopmental Disorders, Phenotype, Syndrome

The DNA damage-binding protein 1 (DDB1) is part of the CUL4-DDB1 ubiquitin E3 ligase complex (CRL4), which is essential for DNA repair, chromatin remodeling, DNA replication, and signal transduction. Loss-of-function variants in genes encoding the complex components CUL4 and PHIP have been reported to cause syndromic intellectual disability with hypotonia and obesity, but no phenotype has been reported in association with DDB1 variants. Here, we report eight unrelated individuals, identified through Matchmaker Exchange, with de novo monoallelic variants in DDB1, including one recurrent variant in four individuals. The affected individuals have a consistent phenotype of hypotonia, mild to moderate intellectual disability, and similar facies, including horizontal or slightly bowed eyebrows, deep-set eyes, full cheeks, a short nose, and large, fleshy and forward-facing earlobes, demonstrated in the composite face generated from the cohort. Digital anomalies, including brachydactyly and syndactyly, were common. Three older individuals have obesity. We show that cells derived from affected individuals have altered DDB1 function resulting in abnormal DNA damage signatures and histone methylation following UV-induced DNA damage. Overall, our study adds to the growing family of neurodevelopmental phenotypes mediated by disruption of the CRL4 ubiquitin ligase pathway and begins to delineate the phenotypic and molecular effects of DDB1 misregulation.

Alternate JournalAm J Hum Genet
PubMed ID33743206
PubMed Central IDPMC8059373
Grant ListUM1 HG008900 / HG / NHGRI NIH HHS / United States
U01 HG009599 / HG / NHGRI NIH HHS / United States
/ / CIHR / Canada