The phenotypic features of TKS related to the p.Tyr64Cys variant in CDC42 comprise psychomotor developmental delay, intellectual disability, dysmorphism, sensorineural hearing loss, cardiac and genitourinary malformations, and macrothrombocytopenia (Takenouchi et al., 2015; Takenouchi et al., 2016; Martinelli et al., 2018; Motokawa et al., 2018; Uehara et al., 2019; Bucciol et al., 2020; Ishikawa et al., 2021; Santoro et al., 2021), consistent also with the herein reported patient. Here, CDC42 is linked to macrothrombocytopenia-lymphedema-developmental delay-facial dysmorphism-camptodactyly syndrome.