Abstracts

Rationale: Tuberous sclerosis complex is a genetic disorder with a an autosomal dominant pattern of inheritance ,characterized by abnormal cellular proliferation and differentiation involving multiple organs, typically the brain. Genetic linkage studies of familial cases of TSC led to discovery of two genes TSC1 and TSC2 , encoding respectively fro hamartin and tuberin protein, TSC1 on chromosome 9q34 and TSC2 on chromosome 16q13 .Brain is involved in 80-90% of cases of TSC, but clinical phenotype is highly heterogeneous with a neurological phenotype ranging from mild to severe. On pathological point of view, TSC associated central nervous system abnormalities are well known and include: cortical tubers, subependymal calcified nodules in the lateral walls of lateral ventricules, white matter heterotopias, giant cell astrocytomas in various combination.There are very few reports focused on white matter abnormalities in the structure of the brain with TSC ( Griffith , 1998; Ridler 2001).In previous reports ( Griffiths, 98) white matters abnormalities related to tubers were found in most of cases. In 20% of cases white matter abnormalities were found that were not related to cortical tubers and radial migration lines were seen infrequently in relation to cortical tubers ( Griffiths, 98) . Ridler et al. found white matter abnormalities in patients with TSC and they showed that they were not significantly correlated with the number of tubers counted with brain MRI. In this study we present a sample of TSC patients in which radial white matter lines related to cortical tubers were more frequent than before hypothesized. Methods: We studied 27 consecutive patients with diagnosis of TSC (18 females, 9 males aged between 5-48, mean 26). MR image acquisitionA preliminary localizing scan in the sagittal plane was used to prescribe acquisition of a Dual- echo, dataset. T2-weighted images were acquired providing the whole brain coverage. Brain MRI was performed at 1.0 Tesla (Philips, Intera NT) using 3-6 mm thickness axial/sagittal T1-w spin-echo (SE) and axial T2-w. Fast-SE, coronal Inversion Recovery (IR), Fluid Attenuated Inversion Recovery (FLAIR) and Gd enhanced axial/coronal T1-w- SE sequences. We set-up this particular protocol to the best detection of all the possible alterations related to TSC. FLAIR, IR and SE data acquired from patients with TSC were carefully visually inspected by two neuroradiologists having a particular competence on TSC lesions.The total number and localization of tubers , subependymal nodules and white matter lesions have been described in each patient by the two radiologists separately.Both agreed in all cases. The counts and morphology of white matter abnormalities were examined in relation to the presence of cortical tubers. Results: White matter abnormalities were present in 75 % of patients and white matter migration lines line were related to cortical tubers in 45%off patients. Conclusions: White matter abnormalities not in relation to cortical tubers in TSC are more frequent than before suspected ( 45% of our patients) and considering the high frequency of presence of white matter lesions, even, in many cases in absence of major brain lesions , as tubers ,white matter abnormalities are probably an underdiagnosed “minor”criteria. Funding: No funding was received in support of this abstract