Mutations in DONSON disrupt replication fork stability and cause microcephalic dwarfism

Research output: Contribution to journalArticlepeer-review


  • Audrey Vernet
  • Rachel Mottram
  • Alexander Brean
  • Fowzan S Alkuraya
  • Christopher G Mathew
  • Andrew P Jackson

Colleges, School and Institutes

External organisations

  • University of Birmingham


To ensure efficient genome duplication, cells have evolved numerous factors that promote unperturbed DNA replication, and protect, repair and restart damaged forks.

Here we identify DONSON as a novel fork protection factor, and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a replisome component that stabilises forks during genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATR-dependent signalling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity, and potentiating chromosomal instability. Hypomorphic mutations substantially reduce DONSON protein levels and impair fork stability in patient cells, consistent with defective DNA replication underlying the disease phenotype.

In summary, we identify mutations in DONSON as a common cause of microcephalic dwarfism, and establish DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.


Original languageEnglish
Pages (from-to)537–549
JournalNature Genetics
Early online date13 Feb 2017
Publication statusPublished - Apr 2017


  • Microcephaly, Microcephalic dwarfism , DNA Damage, ATR, DNA Replication, Replication Stress, DONSON