MRI T2 Mapping of Dorsal Root Ganglia Reveals Increased T2 Relaxation Time in Classical Fabry Disease

Background/Objectives: Fabry disease (FD) is a rare X-linked lysosomal storage disorder characterised by progressive glycolipid accumulation affecting multiple organs, including the peripheral nervous system. The dorsal root ganglia (DRG) play a key role in Fabry-related neuropathy, but non-invasive biomarkers of DRG involvement and their association with overall disease severity remain limited. This study evaluated lumbosacral DRG T2 relaxation time (DRG-T2) in FD patients as a potential imaging biomarker of FD severity. Methods: In a prospective, single-centre study, 80 genetically confirmed FD patients underwent 3T MRI with quantitative T2 mapping of the lumbosacral DRG. DRG-T2 was analysed in relation to sex, genetic subtype and Fabry-specific biomarkers. Results: Results showed that DRG-T2 was higher in patients with classical FD mutations than in those with nonclassical mutations (p = 0.03). Furthermore, DRG-T2 showed a negative correlation with body weight (ρ = -0.31, p = 0.005) and BMI (ρ = -0.32, p = 0.004), while no associations were found with lyso-Gb3 levels or alpha-galactosidase A activity. The inter-rater and test-retest reliability of DRG-T2 were good to excellent (ICC = 0.76 and 0.89, respectively). Conclusions: These results demonstrate DRG-T2 as a marker of neuronal involvement, making it a strong and reliable imaging biomarker of disease severity in FD. However, future studies need to correlate its changes with clinical and histological studies.