Although a common SPAST c.1099-1G>A variant was found in a European-ancestry proband (Table 3), which accounts for 60%−80% of AD-HSP cases in European and Asian cohorts (40, 41), we did not find SPAST variants (including structural variants) in our African-ancestry patients (n = 8 with HSP) even after visual inspection of WGS data on IGV and by using ClinSV. This evidence concerns the gene SPAST and Alzheimer disease.