Periventricular nodular heterotopia 1

A developmental disorder characterized by the presence of periventricular nodules of cerebral gray matter, resulting from a failure of neurons to migrate normally from the lateral ventricular proliferative zone, where they are formed, to the cerebral cortex. PVNH1 is an X-linked dominant form. Heterozygous females have normal intelligence but suffer from seizures and various manifestations outside the central nervous system, especially related to the vascular system. Hemizygous affected males die in the prenatal or perinatal period.

Lissencephaly 8

A form of lissencephaly, a disorder of cortical development characterized by agyria or pachygyria and disorganization of the clear neuronal lamination of normal six-layered cortex. LIS8 patients manifest delayed psychomotor development, intellectual disability with poor or absent speech, early-onset refractory seizures, hypotonia, cortical gyral abnormalities, and hypoplasia of the corpus callosum, brainstem and cerebellum. LIS8 inheritance is autosomal recessive.

Periventricular nodular heterotopia 6

A form of 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. PVNH6 results in delayed psychomotor development, delayed speech, strabismus, and onset of seizures with hypsarrhythmia in early infancy.

Periventricular nodular heterotopia 9

A form of 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. PVNH9 is an autosomal dominant disorder with incomplete penetrance, characterized by impaired intellectual development, cognitive defects, learning disabilities, and behavior abnormalities. Some patients develop seizures.

Periventricular nodular heterotopia 2

A developmental disorder characterized by the presence of periventricular nodules of cerebral gray matter, resulting from a failure of neurons to migrate normally from the lateral ventricular proliferative zone, where they are formed, to the cerebral cortex. PVNH2 is an autosomal recessive form characterized by microcephaly (small brain), severe developmental delay and recurrent infections. No anomalies extrinsic to the central nervous system, such as dysmorphic features or grossly abnormal endocrine or other conditions, are associated with PVNH2.

Periventricular nodular heterotopia 7

A form of 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. PVNH7 is an autosomal dominant disease characterized by delayed psychomotor development, intellectual disability, and seizures in some patients. Additional features include cleft palate and toe syndactyly.

Periventricular nodular heterotopia 8

A form of 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. PVNH8 is an autosomal dominant disease characterized by developmental disabilities, speech delay, seizures and attention deficit-hyperactivity disorder.