A Case of Neuronal Heterotopia

Neuronal migrational disorders of the brain represent abnormalities in the formation of the neocortex caused by faulty migration of the subependymal neuroblasts. The neuroblasts normally migrate between the sixth and 15th gestational week and in doing so form the six-layered neocortex. When the migration does not occur in a normal fashion the resultant brain anomalies include lissencephaly, pachygyria, schizencephaly, hemimegalencephaly, heterotopia, and polymicrogyria. Neuronal heterotopia is a collection of nerve cells in abnormal locations as a result of arrest of their radial migration, improper formation, or destruction of the radial glial fiber. We reported a case of neuronal heterotopia with brief review of related literatures.

A Case of Tetrasomy 9P

Supernumerary isochromosome resulting in autosomal tetrasomy are rare and have been described only for 12P, 18P, and 9P. Tetrasomy 9P, initially described by Ghymer et al, is a rare chromosomal aberration that has been described in 20 patients. Affected subjects show both cytogenetic and ohenotypic variability. Some patients have the abnormal cell line in all cells, but many display tissue limited mosaicism. The phenotype varies in severity from prenatal death to mild developmental delay and minor anomalies. We reported a infant with mild manifestations of tetrasomy 9p with brief review of related literatures.