Crook Crook R R Verkkoniemi Verkkoniemi A A Perez-Tur Perez-Tur J J A variant of Alzheimer’s disease with spastic paraparesis and unusual plaques due to deletion of exon 9 of presenilin 1 A variant of Alzheimer’s disease with spastic paraparesis and unusual plaques due to deletion of exon 9 of presenilin 1 Nat Med Nat Med 1998 1998 4 4 452 452 455 455 10.1038/nm0498-452 10.1038/nm0498-452 supplied-pmid 9546792? This evidence concerns the gene PSEN1 and Alzheimer disease.