Tuberous sclerosis complex: Clinical, genetic and 7T-MRI neuroimaging findings

Background

Tuberous sclerosis complex (TSC) is a multisystemic disorder caused by monoallelic pathogenic variants in TSC1 or TSC2 genes. Neuropathological hallmark is the presence of cortical and subcortical tubers, among others. Epilepsy affects up to 85 %.

Aims

The objective was to correlate the number and location of tubers with neuropsychological and genetic characteristics in three groups of TSC patients: with active epilepsy, controlled epilepsy and without epilepsy.

Methods

Brain 7T-MRI study was performed in 30 subjects with TSC who had previously done brain conventional MRI. Molecular analysis of TSC1 and TSC2 was conducted post-enrollment. Data on epilepsy characteristics, neuropsychological performance and regional and total tuber counts as seen on 7T-MRI, were collected.

Results

Tuber counting in the frontal lobe was significantly higher in the group with active epilepsy compared to the groups with controlled or without epilepsy (p = 0.008). Total and frontal tuber count were significantly higher in individuals with TSC2 variants. Total, verbal and executive intelligence quotient (IQ) scores were significantly higher in the group without epilepsy compared to the controlled epilepsy group. Attention deficit/hyperactivity disorder (ADHD) was less frequent in the group without epilepsy.

Conclusion

Severity of epilepsy in TSC correlates with the number of tubers, especially in the frontal lobe, and with the TSC2 deleterious variant. Future studies involving a larger number of patients may provide new insights into advanced imaging epilepsy biomarkers.