Another example has been reported by Sheen and colleagues who identified loss-of-functions mutations in the ADP-ribosylation Factor Guanine Exchange Factor 2 (ARFGEF2) in patients with an autosomal recessive periventricular heterotopia with microcephaly (ARPHM; MIM #608097) [129]. The gene discussed is ARFGEF2; the disease is microcephaly.