Further evidence of a mutation in CDC42 as a cause of a recognizable syndromic form of thrombocytopenia.

We previously documented a girl with macrothrombocytopenia and developmental delay who carried a de novo mutation in CDC42, which plays pivotal roles in the cell cycle and the formation of the actin cytoskeleton. The phenotype of mice lacking Cdc42 was strikingly similar to that of the reported patient, indicating that the mutation in CDC42 causes a new syndromic form of thrombocytopenia. We, herein, report another unrelated female patient with a similar phenotype and a de novo mutation in the same CDC42. The present observation provides further evidence supporting the notion that a mutation in CDC42 causes a recognizable syndromic form of thrombocytopenia. The cardinal features of this entity include macrothrombocytopenia, developmental delay, lymphedema in the lower extremities, camptodactyly, and distinctive facial features.