Interestingly, the patient reported by Kirchhoff et al. [15] appears to lack a duplication of the KANSL1 gene but has a full duplication of the MAPT and CRHR1 genes and manifests similar psychomotor development, more severe psychomotor retardation, poorer verbal skills, and microcephaly in comparison to this case. Here, KANSL1 is linked to microcephaly.