ASPM is a major determinant of cerebral cortical size.

Bibliographic Collection: 
MOCA Reference, APE
Publication Type: Journal Article
Authors: Bond, Jacquelyn; Roberts, Emma; Mochida, Ganesh H; Hampshire, Daniel J; Scott, Sheila; Askham, Jonathan M; Springell, Kelly; Mahadevan, Meera; Crow, Yanick J; Markham, Alexander F; Walsh, Christopher A; Woods, C Geoffrey
Year of Publication: 2002
Journal: Nat Genet
Volume: 32
Issue: 2
Pagination: 316-20
Date Published: 2002 Oct
Publication Language: eng
ISSN: 1061-4036
Keywords: Anthropometry, Blotting, Northern, Cerebral Cortex, Codon, Nonsense, Drosophila Proteins, Female, Humans, Male, Microcephaly, Microtubule-Associated Proteins, Nerve Tissue Proteins, Pedigree, Sequence Analysis, DNA

One of the most notable trends in mammalian evolution is the massive increase in size of the cerebral cortex, especially in primates. Humans with autosomal recessive primary microcephaly (MCPH) show a small but otherwise grossly normal cerebral cortex associated with mild to moderate mental retardation. Genes linked to this condition offer potential insights into the development and evolution of the cerebral cortex. Here we show that the most common cause of MCPH is homozygous mutation of ASPM, the human ortholog of the Drosophila melanogaster abnormal spindle gene (asp), which is essential for normal mitotic spindle function in embryonic neuroblasts. The mouse gene Aspm is expressed specifically in the primary sites of prenatal cerebral cortical neurogenesis. Notably, the predicted ASPM proteins encode systematically larger numbers of repeated 'IQ' domains between flies, mice and humans, with the predominant difference between Aspm and ASPM being a single large insertion coding for IQ domains. Our results and evolutionary considerations suggest that brain size is controlled in part through modulation of mitotic spindle activity in neuronal progenitor cells.

DOI: 10.1038/ng995
Alternate Journal: Nat. Genet.