Bilateral hippocampal granule cell dispersion: autopsy study of 3 infants

Recent morphologic studies of Ammon's horn sclerosis (AHS) have recorded gr anule cell dispersion (GCD) in a significant proportion of temporal lobes s urgically resected for temporal lobe epilepsy (TLE). We report the first po st-mortem descriptions of GCD in three unrelated infants. GCD was bilateral in all three and there were also migrational defects, heterotopias or poly microgyria. Only one child, a 2.5-year-old boy, presented with a severe sei zural disorder and exhibited bilateral AHS. But in the two younger children , deceased at 12 weeks and 5 months, respectively, no seizures were observe d and hippocampal neuronal populations were intact. To date, GCD has only b een reported in association with epilepsy and has not been observed bilater ally or in neurologically normal individuals. The present observations brin g into question the hypothesis that GCD is causally related to seizure acti vity in early life, suggesting an opposing view that it is an independent d evelopmental disorder.