Heterozygous mutations in the motor domain of DYNC1H1 have been associated with autosomal dominant mental retardation-13 (MRD13) with neuronal migration defects [OMIM: #614563], in which a subset of patients also present with microcephaly along with a small cerebellum and/or brainstem [37, 38]. Here, DYNC1H1 is linked to microcephaly.