Malformations of cortical development

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Suggested imaging sequences/techniques

Identification and proper diagnosis of cortical malformations depends on performing the proper imaging studies and, if possible, performing them at ages that allow optimization of contrast between gray matter and white matter. Magnetic resonance imaging is the most useful single study in this group of patients, as the excellent contrast between gray matter and white matter allows an accurate topologic assessment of gyral and sulcal development, assessment of the junction of the cortex and white

Fundamental embryology of the brain

During the process of closure of the neural tube, the neuroepithelium lining the central canal of the developing embryo is induced to begin a series of cell divisions [3]. This region of dividing cells is called a germinal zone, or germinal matrix [4]. The developing brain has multiple germinal zones, each one producing a specific set of cells that will migrate through the developing brain using a series of guidance signals [5], [6], [7]. The neurons developing in the neocortical germinal zone

Malformations due to abnormal neuronal and glial proliferation or apoptosis

Malformations resulting from abnormal cell proliferation or apoptosis can have abnormal cells due to abnormal cell differentiation, microcephaly from decreased cell proliferation or increased apoptosis, or macrocephaly from increased cell proliferation or decreased apoptosis [1]. Normal function is not seen in the affected portions of these brains [17]. The major malformations in the group are hemimegalencephaly, microlissencephaly/microcephaly with simplified gyral pattern, cortical dysplasia

Malformations secondary to abnormal neuronal migration

Malformations secondary to abnormal neuronal migration are a diverse group of malformations in which the movement of neurons from the germinal zone to the cerebral cortex is disturbed. Normally, neurons generated in the walls of the lateral ventricles migrate away from the ventricular surface in a pathway perpendicular to the wall of the ventricle. Because the distance to the neocortex is long compared with the size of the cell, special migration mechanisms have evolved to aid in the migration.

Malformations secondary to abnormal late migration and organization

The last group of disorders to be discussed includes malformations believed to result from developmental abnormalities that occur or are expressed either at the time the neurons reach the cortex or after they reach the cortex and start to establish local and remote synapses. By far the most frequent malformation in this group that is readily identified by imaging is polymicrogyria. Because polymicrogyria has many similarities to schizencephaly, and because the two malformations are commonly

Summary

Malformations of cortical development are an important cause of developmental delay and epilepsy. Proper identification of these malformations can greatly help in accurately counseling affected families and, in some cases, in the treatment of the epilepsy. Modern neuroimaging is an important tool in the diagnosis of these malformations.

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References (175)

  • V. Dubowitz

    Workshop report: 22nd ENMC sponsored workshop on congenital muscular dystrophy held in Baarn, the Netherlands, 14–16 May 1993

    Neuromusc Disord

    (1994)
  • V. Dubowitz et al.

    Workshop report: 27th ENMC sponsored workshop on congenital muscular dystrophy held in Schipol, the Netherlands, 15–17 April 1994

    Neuromusc Disord

    (1995)
  • Y. Fukuyama et al.

    Congenital progressive muscular dystrophy of the Fukuyama type—clinical, genetic, and pathological considerations

    Brain Dev

    (1981)
  • P. Santavuori et al.

    Muscle-eye-brain disease

    Brain Dev

    (1989)
  • M. Yoshioka et al.

    A variant of congenital muscular dystrophy

    Brain Dev

    (2002)
  • A. Pini et al.

    Merosin-negative congenital muscular dystrophy, occipital epilepsy with periodic spasms and focal cortical dysplasia. Report of three Italian cases in two families

    Brain Dev

    (1996)
  • B. Talim et al.

    Merosin-deficient congenital muscular dystrophy with mental retardation and cerebellar cysts unlinked to the LAMA2, FCMD and MEB loci

    Neuromuscul Disord

    (2000)
  • A.J. Barkovich et al.

    Classification system for malformations of cortical development: update 2001

    Neurology

    (2001)
  • A.J. Barkovich et al.

    A classification scheme for malformations of cortical development

    Neuropediatrics

    (1996)
  • F. Müller et al.

    The human brain at stages 21–23, with particular reference to the cerebral cortical plate and to the development of the cerebellum

    Anat Embryol

    (1990)
  • O. Marin et al.

    A long remarkable journey: tangential migration in the telencephalon

    Nature Rev

    (2001)
  • M. Tessier-Lavigne et al.

    The molecular biology of axon guidance

    Science

    (1996)
  • S. Alcantara et al.

    Netrin 1 acts as an attractive or as a repulsive cue for distinct migrating neurons during the development of the cerebellar system

    Development

    (2000)
  • P. Rakic

    Neuronal migration and contact guidance in the primate telencephalon

    Postgrad Med J

    (1978)
  • O. Marı́n et al.

    Origin and molecular specification of striatal interneurons

    J Neurosci

    (2000)
  • C.-M. Chuong

    Differential roles of multiple adhesion molecules in cell migration: granule cell migration in cerebellum

    Experientia

    (1990)
  • J.C. Lin et al.

    The external granule layer of the developing chick cerebellum generates granule cells and cells of the isthmus and rostral hindbrain

    J Neurosci

    (2001)
  • P. Rakic et al.

    Histogenesis of cortical layers in human cerebellum, particularly the lamina dessicans

    J Comp Neurol

    (1970)
  • H. Komuro et al.

    Mode and tempo of tangential cell migration in the cerebellar external granular layer

    J Neurosci

    (2001)
  • M. Packard et al.

    Wnts and TGF beta in synaptogenesis: old friends signalling at new places

    Nat Rev Neurosci

    (2003)
  • A. Ebner et al.

    Functional organization of the brain with malformations of cortical development

    Ann Neurol

    (2003)
  • W. Dobyns et al.

    Microcephaly with simplified gyral pattern (oligogyric microcephaly) and microlissencephaly

    Neuropediatrics

    (1999)
  • A.J. Barkovich et al.

    Microlissencephaly: a heterogeneous malformation of cortical development

    Neuropediatrics

    (1998)
  • L. Sztriha et al.

    Autosomal recessive micrencephaly with simplified gyral pattern, abnormal myelination and arthrogryposis

    Neuropediatrics

    (1999)
  • L. Klinge et al.

    Microlissencephaly in microcephalic osteodysplastic primordial dwarfism: case report and review of the literature

    Neuropediatrics

    (2002)
  • L. Basel-Vanagaite et al.

    New syndrome of simplified gyral pattern, micromelia, dysmorphic features, and early death

    Am J Med Genet

    (2003)
  • M. Sarwar et al.

    Brain malformations in linear nevus sebaceous syndrome: an MR study

    J Comput Assist Tomogr

    (1988)
  • L. Pavone et al.

    Epidermal nevus syndrome: a neurologic variant with hemimegalencephaly, gyral malformation, mental retardation, seizures, and facial hemihypertrophy

    Neurology

    (1991)
  • R.B. Dietrich et al.

    The proteus syndrome: CNS manifestations

    AJNR Am J Neuroradiol

    (1998)
  • P.D. Griffiths et al.

    The radiological features of hemimegalencephaly including three cases associated with proteus syndrome

    Neuropediatrics

    (1994)
  • A. Peserico et al.

    Unilateral hypomelanosis of Ito with hemimegalencephaly

    Acta Paediatr Scand

    (1988)
  • R. Cusmai et al.

    Hemimegalencephaly and neurofibromatosis

    Neuropediatrics

    (1990)
  • R.D. Dhamecha et al.

    Klippel-Trenaunay-Weber syndrome with hemimegalencephaly

    J Craniofac Surg

    (2001)
  • P.D. Griffiths et al.

    Hemimegalencephaly and focal megalencephaly in tuberous sclerosis complex

    AJNR Am J Neuroradiol

    (1998)
  • P. Galluzzi et al.

    Hemimegalencephaly in tuberous sclerosis complex

    J Child Neurol

    (2002)
  • C.L. Kalifa et al.

    Hemimegalencephaly: MR imaging in five children

    Radiology

    (1987)
  • L. Flores-Sarnat et al.

    Hemimegalencephaly

  • A.J. Barkovich et al.

    Unilateral megalencephaly: correlation of MR imaging and pathologic characteristics

    AJNR Am J Neuroradiol

    (1990)
  • O. Robain et al.

    Neuropathology of hemimegalencephaly

  • J.J. Townsend et al.

    Unilateral megalencephaly: hamartoma or neoplasm?

    Neurology

    (1975)
  • Cited by (0)

    This article is adapted from Barkovich AJ, Raybaud CA. Neuroimaging in disorders of cortical development. Neuroimag Clin N Am 2004;14:231–54.

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