Among the three neurocognitive outcomes, prior to fine-mapping, the METRO TWAS identified the ICA1L gene overlapping between WMH (α = −0.27; p = 5.44 × 10−12) and AD (from EA GWAS; α = −0.06; p = 2.68 × 10−6); the FMNL1 gene overlapping between WMH (α = 0.54; p = 1.39 × 10−8) and general cognitive function (α = 0.17; p = 2.15 × 10−6); and 22 genes enriched in AD-related pathways and functions overlapping between general cognitive function and AD (from EA GWAS) (Figure 3a and Figure S1). Here, ICA1L is linked to Alzheimer disease.