Brain MRI, the specifications of the Kif4a mutation in patients’ family and the sequence alignment of KIF4. (A) Brain MRI in the IV-3 patient exhibited unremarkable MRI features. (B) Whole exome sequencing of the Kif4a gene in controls and patients was performed on DNA extracted from blood samples. Arrows (red) indicate the position of the mutation. Genotyping results for the parents III-1/2 and the children IV-1/2/3 were as follows: III-1, X^WTX^Mut; III-2, X^WTY; IV-1/2, X^WTX^Mut; and IV-3, X^MutY. (C) Multiple sequence alignment of the KIF4 coiled–coil region from the indicated species. R728 is highly conserved in KIF4 throughout evolution.