However, it is also important to consider that increased FA is not always beneficial; for example, visuospatial deficits in William’s syndrome have been associated with increased FA in the right SLF.79 Several factors could lead to increased FA, including increased myelination and axonal density or decreased axonal diameter, membrane permeability, and branching.80–82 Therefore, the negative loading of syntax performance could be due to abnormal increases in FA in the SLFp, SLFt, or ILF. The gene discussed is FOXK2; the disease is Williams syndrome.