Heterozygous missense variants in CDC42 have recently been associated with a heterogeneous developmental disorder that includes variable growth dysregulation, facial dysmorphism, and neurodevelopmental, immunological, and hematological abnormalities (MIM: 616737, Takenouchi-Kosaki syndrome).34 This evidence concerns the gene CDC42 and macrothrombocytopenia-lymphedema-developmental delay-facial dysmorphism-camptodactyly syndrome.