On 2 October, Dr Tavares and colleagues published a paper in the Neurology journal, showing that people who go on to develop genetic frontotemporal dementia (FTD) have larger brain ventricle volumes on MRI scans when compared to relatives who are not carriers of FTD risk genes. 30% of people with genetic FTD are carriers of mutations in the MAPT,PGRNorC9Forf72genes. Previous clinical studies have shown that people with symptomatic genetic FTD (also known as “familial FTD”) present with enlargement of their brain ventricles, cavities within the brain that contain cerebrospinal fluid. Brain ventricle enlargement is visible on brain imaging scans, and clinicians often use 3D MRI scans to calculate brain ventricle volume, using this as a diagnostic tool for neurodegenerative diseases such as FTD. However, it is not yet known whether increases in brain ventricle volume can also be seen before FTD symptoms develop, when treatment is likely to have maximal benefits.
To answer this question, Dr Tavares and colleagues performed MRI scans on participants in the multi-center, international Genetic Frontotemporal Dementia Initiative (GENFI) cohort study. These participants included presymptomatic and symptomatic FTD mutation carriers, as well as their non-carrier, unaffected relatives. Using an image analysis technique called “automated segmentation”, the researchers showed that non-carrier, healthy individuals had lower brain ventricle volumes than people who carried FTD mutations and then went on to develop symptomatic disease. The increase in brain ventricle volume in people with presymptomatic FTD could be observed from 49 years of age on average, 4 years before disease symptoms developed. Ventricular volume may therefore be a useful index of disease symptom onset in the prodromal, non-symptomatic stages of FTD.
https://n.neurology.org/content/early/2019/10/02/WNL.0000000000008386
