Objective: Point mutations and deletions within the SOX11gene have recently been described in individuals with a rare variant of Coffin-Siris syndrome, OMIM 615866, an intellectual disability syndrome with associated features of nail hypoplasia, microcephaly, and characteristic facial features including a wide mouth and prominent lips.Participant: We describe a further patient with a mutation in SOX11and phenotype resembling mild Coffin-Siris syndrome.Results: This boy had a cleft palate, a feature not previously seen in other patients with SOX11mutations.Conclusion: We discuss This adds to the current evidence that SOX11is a gene involved in palatogenesis.