In humans, individuals carrying heterozygous loss-of-function mutations in SOX2 mainly have ocular phenotypes (anophthalmia/microphthalmia), but some patients also present with microcephaly and other variable phenotypes, including hippocampal abnormalities, epilepsy, and motor problems, as well as dysmorphic facial features and genital anomalies (Fantes et al., 2003; Sisodiya et al., 2006; Schneider et al., 2009; Blackburn et al., 2018). This evidence concerns the gene SOX2 and microcephaly.