Molecular genetics of human microcephaly : Current Opinion in Neurology (original) (raw)

Review Article

aDivision of Neurogenetics, Department of Neurology, and bClinical Investigator Training Program, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA; cPediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.

Correspondence to Christopher A. Walsh, Department of Neurology, Beth Israel Deaconess Medical Center, Room 816, Harvard Institutes of Medicine, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA. Tel: +1 617 667 0813; fax: +1 617 667 0815; e-mail: [email protected]

Abbreviations

MRI: magnetic resonance imaging

OFC: occipito-frontal circumference

Abstract

Human microcephaly comprises a heterogeneous group of conditions that are characterized by a failure of normal brain growth. Microcephaly can be caused by many injurious or degenerative conditions, or by developmental malformations in which the growth of the brain is impaired as a result of defects in pattern formation, cell proliferation, cell survival, cell differentiation, or cell growth. These latter forms of congenital microcephaly are frequently inherited, usually as recessive traits, and are associated with mental retardation and sometimes epilepsy. Some of the genes that cause congenital microcephaly are likely to control crucial aspects of neural development, and may also be involved in the evolutionary explosion of cortical size that characterizes primates. There has recently been a rapid advance in the use of genetic mapping techniques to identify genetic loci responsible for microcephaly. Although several loci have been mapped, the condition is clearly genetically and clinically heterogeneous.