Abnormal temporal lobe morphology in asymptomatic relatives of patients with hippocampal sclerosis: A replication study

Abstract

We investigated gray and white matter morphology in patients with mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE+HS) and first-degree asymptomatic relatives of patients with mTLE+HS. Using T1-weighted magnetic resonance imaging (MRI), we sought to replicate previously reported findings of structural surface abnormalities of the anterior temporal lobe in asymptomatic relatives of patients with mTLE+HS in an independent cohort. We performed whole-brain MRI in 19 patients with mTLE+HS, 14 first-degree asymptomatic relatives of mTLE+HS patients, and 32 healthy control participants. Structural alterations in patients and relatives compared to controls were assessed using automated hippocampal volumetry and cortical surface-based morphometry. We replicated previously reported cortical surface area contractions in the ipsilateral anterior temporal lobe in both patients and relatives compared to healthy controls, with asymptomatic relatives showing similar but less extensive changes than patients. These findings suggest morphologic abnormality in asymptomatic relatives of mTLE+HS patients, suggesting an inherited brain structure endophenotype.

Keywords: MRI; endophenotype; hippocampal sclerosis; mesial temporal lobe epilepsy.

Figure 1

Surface‐based morphometry results. Clusters showing reduced cortical surface area in patients (red/yellow) and relatives (blue/cyan) compared to controls in the ipsilateral temporal lobe (clusters survive cluster correction at P < 0.05 and Bonferroni correction for 6 comparisons)