The anterior commissure in Down's syndrome.

The area of a mid-sagittal secretion of the anterior commissure was found to be significantly smaller in 16 Down's syndrome patients compared with that of ten control subjects (3.78 mm2 compared with 7.52 mm2). Variables which could have influenced the differences such as brain weight, neuropathological features, relation to olfactory tract and hippocampal sizes were considered and excluded. It was deduced that smallness in size in Down's syndrome was the result of congenital malformation.