Depending on the transporter residual activity, mutations in MFSD2A (MCPH15) gene is associated with either a progressive microcephaly syndrome or a much lethal phenotype (Berger et al., 2012; Alakbarzade et al., 2015; Guemez-Gamboa et al., 2015; Harel et al., 2018; Scala et al., 2020). The gene discussed is MFSD2A; the disease is microcephaly.