Other congenital malformations of brain (Q04)

Clinical Information for Other congenital malformations of brain (Q04)

Hemimegalencephaly - Rare MALFORMATIONS OF CORTICAL DEVELOPMENT, GROUP I characterized by the enlargement of one side of the brain. It is associated with seizures, partial paralysis, and mental retardation.

Megalencephaly - A congenital abnormality in which the occipitofrontal circumference is greater than two standard deviations above the mean for a given age. It is associated with HYDROCEPHALUS; SUBDURAL EFFUSION; ARACHNOID CYSTS; or is part of a genetic condition (e.g., ALEXANDER DISEASE; SOTOS SYNDROME).

Holoprosencephaly - Anterior midline brain, cranial, and facial malformations resulting from the failure of the embryonic prosencephalon to undergo segmentation and cleavage. Alobar prosencephaly is the most severe form and features anophthalmia; cyclopia; severe INTELLECTUAL DISABILITY; CLEFT LIP; CLEFT PALATE; SEIZURES; and microcephaly. Semilobar holoprosencepaly is characterized by hypotelorism, microphthalmia, coloboma, nasal malformations, and variable degrees of INTELLECTUAL DISABILITY. Lobar holoprosencephaly is associated with mild (or absent) facial malformations and intellectual abilities that range from mild INTELLECTUAL DISABILITY to normal. Holoprosencephaly is associated with CHROMOSOME ABNORMALITIES.

Classical Lissencephalies and Subcortical Band Heterotopias - Disorders comprising a spectrum of brain malformations representing the paradigm of a diffuse neuronal migration disorder. They result in cognitive impairment; SEIZURES; and HYPOTONIA or spasticity. Mutations of two genes, LIS1, the gene for the non-catalytic subunit of PLATELET-ACTIVATING FACTOR ACETYLHYDROLASE IB; and DCX or XLIS, the gene for doublecortin, have been identified as the most common causes of disorders in this spectrum. Additional variants of classical (Type I) lissencephaly have been linked to RELN, the gene for reelin, and ARX, the gene for aristaless related homeobox protein. (From Leventer, R.J., et al, Mol Med Today. 2000 Jul;6(7):277-84 and Barkovich, A.J., et al, Neurology. 2005 Dec 27;65(12):1873-87.)

Cobblestone Lissencephaly - The smooth pebbled appearance of the CEREBRAL CORTEX with a thickened cortex and reduced and abnormal white matter, which results from migration of heterotopic neurons beyond the marginal zone into the leptomeninges through gaps in the external BASEMENT MEMBRANE. There is also enlarged ventricles, underdeveloped BRAINSTEM and cerebellum, and absence of the CORPUS CALLOSUM. These abnormalities occur as a syndrome without other birth defects (cobblestone complex) or in other syndromes associated with congenital MUSCULAR DYSTROPHY, often involving the eye, such as the Walker-Warburg Syndrome, Fukuyama congenital muscular dystrophy, and muscle-eye-brain disease.

Doublecortin Protein - A microtubule-associated protein that is primarily found in neuronal precursor cells and immature NEURONS in embryonic and adult cortical structures.

Lissencephaly - A smooth brain malformation of the CEREBRAL CORTEX resulting from the abnormal location of developing neurons during corticogenesis. It is characterized by an absence of normal convoluted indentations on the surface of the brain (agyria), or fewer and shallower indentations (pachygryia). There is a reduced number of cortical layers, typically 4 instead of 6, resulting in a thickened cortex, and reduced cerebral white matter that is a reversal of the normal ratio of cerebral white matter to cortex.

Hydranencephaly - A congenital condition where the greater portions of the cerebral hemispheres and CORPUS STRIATUM are replaced by CSF and glial tissue. The meninges and the skull are well formed, which is consistent with earlier normal embryogenesis of the telencephalon. Bilateral occlusions of the internal carotid arteries in utero is a potential mechanism. Clinical features include intact brainstem reflexes without evidence of higher cortical activity. (Menkes, Textbook of Child Neurology, 5th ed, p307)

Schizencephaly - Cortical malformations characterized by grey matter-lined cleft or cyst that extends from the EPENDYMA often to the PIA MATER outer surface. The grey matter that lines the cleft is often POLYMICROGYRIA. It is associated with developmental delay, motor disturbance and seizures.

Persistent Hyperplastic Primary Vitreous - A developmental ocular anomaly in which the primary VITREOUS BODY and its surrounding hyaloid vasculature failed to regress. It is usually unilateral and characterized by CATARACT; MICROPHTHALMOS (small eyeballs), and retrolenticular fibrovascular tissue. (from Yanoff: Ophthalmology, 2nd ed.)

Hypernatremia - Excessive amount of sodium in the blood. (Dorland, 27th ed)

Agenesis of Corpus Callosum - Birth defect that results in a partial or complete absence of the CORPUS CALLOSUM. It may be isolated or a part of a syndrome (e.g., AICARDI'S SYNDROME; ACROCALLOSAL SYNDROME; ANDERMANN SYNDROME; and HOLOPROSENCEPHALY). Clinical manifestations include neuromotor skill impairment and INTELLECTUAL DISABILITY of variable severity.

Aicardi Syndrome - A rare genetic disorder characterized by partial or complete absence of the CORPUS CALLOSUM, resulting in infantile spasms, MENTAL RETARDATION, and lesions of the RETINA or OPTIC NERVE.

Acrocallosal Syndrome - Autosomal recessive syndrome characterized by hypogenesis or agenesis of CORPUS CALLOSUM. Clinical features include MENTAL RETARDATION; CRANIOFACIAL ABNORMALITIES; digital malformations, and growth retardation.

Pseudobulbar Palsy - A syndrome characterized by DYSARTHRIA, dysphagia, dysphonia, impairment of voluntary movements of tongue and facial muscles, and emotional lability. This condition is caused by diseases that affect the motor fibers that travel from the cerebral cortex to the lower BRAIN STEM (i.e., corticobulbar tracts); including MULTIPLE SCLEROSIS; MOTOR NEURON DISEASE; and CEREBROVASCULAR DISORDERS. (From Adams et al., Principles of Neurology, 6th ed, p489)

Periventricular Nodular Heterotopia - A disorder resulting from a defect in the pattern of neuronal migration in which ectopic collections of neurons lie along the lateral ventricles of the brain or just beneath, contiguously or in isolated patches.

Neurons - The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.

Cerebral Cortex - The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.

Instructional Notations

Type 1 Excludes Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.