ASPM encodes ASPM, a protein localized at the centrosome of apical neural progenitor cells that is involved in mitotic spindle orientation during embryonic neurogenesis27 and is important for the correct proliferation and differentiation of neural progenitor cells during brain development.28 Mutations inthis gene cause autosomal recessive primary microcephaly 5, characterized by ID, microcephaly, sloping forehead, hypoplasia of the corpus callosum, simplified gyral pattern, and speech problems.29,30. The gene discussed is ASPM; the disease is autosomal recessive primary microcephaly.