MRC Human Genetics Unit
Medical Research Council Human Genetics Unit


New microcephaly gene plays key role during DNA replication

Mutations in DONSON, important during DNA replication, lead to primordial dwarfism: February 2017


Research arising from a global collaboration, led by the University of Edinburgh (Professor Andrew P Jackson), he University of Birmingham (Professor Grant S Stewart), Kings College London (Professor Christopher G Mathew) and the King Faisal Specialist Hospital and Research Center in Saudi Arabia (Professor Fowzan S Alkuraya),identified that mutations in the DONSON gene as a frequent cause of genetic microcephaly and reduced body size (microcephalic dwarfism).

This discovery will help with more accurate diagnoses for patients with microcephaly. As well this study has shed new light into the fundamental cellular process of DNA replication, showing that this gene protects DNA while it is being replicated.

DNA replication is the process by which a cell faithfully copies its genetic material, before dividing and passing each copy into two identical daughter cells. Cells from patients with mutations in the DONSON gene have difficulty in efficiently replicating their DNA and protecting the replicated DNA, providing an explanation for why brain size and stature are reduced.

Reynolds et al. (2017) 'Mutations in DONSON disrupt replication fork stability and cause microcephalic dwarfism' Nature Genetics DOI: 10.1038/ng.3790