Variations in CTSD and MnSOD showed no association with the development of AD, whereas the presence of the Ala224Val polymorphism in CTSD had a positive association with the development of AD.
It has been suggested that the C-->T (224Ala-->Val) transition within exon 2 of the cathepsin D gene (CTSD) might represent a risk factor for late onset AD.
A functional polymorphism in exon 2 of the cathepsin D gene (C-->T, Ala224Val) has recently been reported to increase the risk for AD in some of the Caucasian populations, with a significant overrepresentation of the T allele, but these reports have not been universally duplicated.
Meta-analysis of the association of the cathepsin D Ala224Val gene polymorphism with the risk of Alzheimer's disease: a HuGE gene-disease association review.