Location of the DIAPH1 R1213* variant. Schematic representation of the major MK DIAPH1 transcript ENST00000398557, which is predicted to encode the 1272–amino acid DIAPH1 protein. R1213 is 60 amino acids from the carboxyl terminus of DIAPH1 within the DAD. In the amino acid sequence lineup of human DIAPH1 and orthologs, there is conservation of the core MDxLLExL (blue box) and basic RRKR (green box) motifs within the DAD that mediate autoinhibitory interactions with the DID near the amino terminus of DIAPH1. Because R1213 is at position 1 of the basic RRKR motif, R1213* is predicted to cause expression of a truncated DIAPH1 protein with an intact core MDxLLExL motif, but without the basic RRKR motif. CC, coiled-coil; GBD, GTPase-binding domain.