PT - JOURNAL ARTICLE AU - N.K. Rollins TI - Diffusion Imaging of the Congenitally Thickened Corpus Callosum AID - 10.3174/ajnr.A3245 DP - 2012 Aug 16 TA - American Journal of Neuroradiology 4099 - http://www.ajnr.org/content/early/2012/08/16/ajnr.A3245.short 4100 - http://www.ajnr.org/content/early/2012/08/16/ajnr.A3245.full AB - SUMMARY: This report presents 4 subjects with congenital segmental callosal thickening, an uncommon malformation studied with MR imaging and DTI. Medical records were reviewed for genetic testing and neurodevelopmental status. Three subjects had profound developmental delay; 3 had seizures. MR imaging showed segmental thickening of the rostral and/or midcallosal body. Associated anomalies included polymicrogyria in 1 patient and optic hypoplasia in 1. DTI showed that the segmental thickening was due to anomalous longitudinal supracallosal fibers visually separable from the paired cingulum in 3 patients; in 1 patient, the cingulum was poorly formed. Genetic testing was negative for Fragile X syndrome. Microarray DNA analysis showed 3 copy losses (2q27.3, 3p21.31, 7q21.11) and 1 copy gain (8p11.23) in 1 patient, while testing in the other subject was negative for losses or gains. Potential explanations for the anomalous fibers include heterotopic cingulum, an enlarged indusium griseum, and aberrant callosal fibers. Abbreviations FAfractional anisotropyIGindusium griseumM-CMTCmarmorata telangiectatica congenita syndromeNFneurofibromatosis