Table 2.
Summary of sample characteristics, methodology and main findings for studies of FAD genes.
| Study | Gene | N (FAD carriers; non-carriers) | Mean Age (SD) | dMRI Method | Field Strength (T) | B value (s/mm2) | Acquisition Voxel Size (mm) | N Directions | NEX | Region of Interest | Results |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Caballero et al, 2018 | PS1, PS2, APP | 109 (64; 45) | Symptomatic & pre-symptomatic 38.8 (10.6); Non-carriers 38.0 (11.2) |
TBSS | 3 | 0, 1000 | 0.9 × 0.9 × 5.0 | 64 | 1 | Whole brain | • Symptomatic & pre-symptomatic carriers: ↑ MD in posterior parietal & medial frontal regions |
| Li et al, 2015 | APP, PS1 | 30 (10; 20) | Symptomatic 46.5 (9.3); Pre-symptomatic 42.7 (8.4); Non-carriers 48.4 (15.1) |
TBSS | 3 | 0, 1000 | 1 × 1 × 1 | 30 | 1 | Cingulum, superior longitudinal fasciculus, inferior longitudinal fasciculus | • Pre-symptomatic carriers vs controls: ↑ MD left inferior longitudinal fasciculus, left forceps major, right & left superior longitudinal fasiculus, left cingulum • Symptomatic & pre-symptomatic vs controls: pattern as above, differences ↑ |
| Parra et al, 2015. | PS1 | 58 (22; 14) | Symptomatic 47.5 (6.4); Pre-symptomatic 35.1 (5.5); Non-carriers 39.3 (8.3) |
VBA | 1.5 | 0, 1000 | 1.72 × 1.72 × 3 | 12 | 1 | Parahippocampal cingulum, genu & splenium of corpus callosum, frontal white matter, parahippocampal cingulum, centrum semiovale | • Pre-symptomatic carriers vs controls: no significant differences • Symptomatic carriers vs controls: ↑ MD in parahippocampal cingulum, left splenium, genu bilaterally, left inferolateral frontal white matter |
| Ringman et al, 2007 | APP, PS1 | 20 (12; 8) | Symptomatic [age not reported]; Pre-symptomatic 32 (6.4); Non-carriers 36 (6.2) |
VBA | 1.5 | 0, 1000 | 3 × 3 × 3 | 6 | 1 | Genu & splenium of corpus callosum, frontal white matter, fornix, cingulum, perforant path, corticopsinal tract, whole brain | • Pre-symptomatic carriers vs controls: ↓ FA fornix & frontal white matter • Symptomatic & pre-symptomatic carriers vs controls: ↓ mean FA whole brain, ↓ FA left frontal white matter, right & left perforant path |
| Ryan et al, 2013 | PS1 | 40 (20; 20) | Symptomatic 49.0 (9.4); Presymptomatic 37.8 (4.7); Non-carriers 44.3 (12.7) |
TBSS | 3 | 1000 | 1.1 × 1.1 × 1.1 | 64 | 1 | Fornix, cingulum, corpus callosum | • Pre-symptomatic carriers vs. controls: ↓ MD & RD in right cingulum • Symptomatic carriers vs controls: ↓ FA, ↑ MD & LD in all tracts |
| Sanchez-Valle et al, 2016 | PS1 | 36 (22; 14) | Symptomatic 46.63 (9.1); Pre-symptomatic 39.2 (10.4); Non-carriers 39.0 (9.5) |
VBA | 3 | 0 | 2 × 2 × 2 | 30 | 1 | Whole brain | • Pre-symptomatic carriers vs controls: no significant differences • Symptomatic carriers vs controls: ↓ FA with ↑ relative age ratio in genus & body of corpus callosum & corona radiate; ↑ MD, LD, RD with ↑ relative age ratio in splenium |
Please note that we report findings from the most rigorous analyses conducted by studies, including models controlling for multiple comparisons. When not otherwise reported, NEX was assumed to be 1. Acronyms: dMRI = diffusion Magnetic Resonance Imaging; PS1 = Presinillin 1; APP = Amyloid Precursor Protein; TBSS = Tract-Based Spatial Statistics; VBA = Voxel-Based Analysis; ROI = Region of Interest; FA = Fractional Anisotropy; MD = Mean Diffusivity; RD = Radial Diffusivity; LD = Longitudinal Diffusivity.